U.S. patent application number 14/860083 was filed with the patent office on 2016-01-14 for method and apparatus for multi-antenna transmission in uplink.
This patent application is currently assigned to INTERDIGITAL PATENT HOLDINGS, INC.. The applicant listed for this patent is InterDigital Patent Holdings, Inc.. Invention is credited to Lujing Cai, Benoit Pelletier, Fenguin Xi, Hong Zhang.
Application Number | 20160013890 14/860083 |
Document ID | / |
Family ID | 43735146 |
Filed Date | 2016-01-14 |
United States Patent
Application |
20160013890 |
Kind Code |
A1 |
Xi; Fenguin ; et
al. |
January 14, 2016 |
METHOD AND APPARATUS FOR MULTI-ANTENNA TRANSMISSION IN UPLINK
Abstract
Method and apparatus for uplink transmission using multiple
antennas are disclosed. A wireless transmit/receive unit (WTRU)
performs space time transmit diversity (STTD) encoding on an input
stream of a physical channel configured for STTD. Each physical
channel may be mapped to either an in-phase (I) branch or a
quadrature-phase (Q) branch. The WTRU may perform the STTD encoding
either in a binary domain or in a complex domain. Additionally, the
WTRU may perform pre-coding on at least one physical channel
including the E-DPDCH with the pre-coding weights, and transmitting
the pre-coded output streams via a plurality of antennas. The
pre-coding may be performed either after or before spreading
operation.
Inventors: |
Xi; Fenguin; (San Diego,
CA) ; Cai; Lujing; (Morganville, NJ) ; Zhang;
Hong; (Manalapan, NJ) ; Pelletier; Benoit;
(Roxboro, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
InterDigital Patent Holdings, Inc. |
Wilmington |
DE |
US |
|
|
Assignee: |
INTERDIGITAL PATENT HOLDINGS,
INC.
Wilmington
DE
|
Family ID: |
43735146 |
Appl. No.: |
14/860083 |
Filed: |
September 21, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14172615 |
Feb 4, 2014 |
9143213 |
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14860083 |
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13718177 |
Dec 18, 2012 |
8665990 |
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14172615 |
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12894556 |
Sep 30, 2010 |
8355424 |
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13718177 |
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61247123 |
Sep 30, 2009 |
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61248313 |
Oct 2, 2009 |
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61356320 |
Jun 18, 2010 |
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Current U.S.
Class: |
370/295 |
Current CPC
Class: |
H04L 27/362 20130101;
H04B 7/0404 20130101; H04L 1/0625 20130101; H04B 7/0623 20130101;
H04B 7/0669 20130101; H04B 7/06 20130101; H04B 7/0456 20130101;
H04L 1/0668 20130101; H04B 7/0617 20130101 |
International
Class: |
H04L 1/06 20060101
H04L001/06; H04B 7/04 20060101 H04B007/04; H04B 7/06 20060101
H04B007/06 |
Claims
1. A method implemented in a wireless transmit/receive unit (WTRU)
for uplink transmission using multiple antennas, the method
comprising: generating a first data stream and a second data
stream; multiplying pre-coding weights to the first data stream and
the second data stream to generate a plurality of output streams;
and transmitting the output streams via a plurality of
antennas.
2. The method of claim 1 wherein the first data stream includes an
E-DCH dedicated physical data channel (E-DPDCH) and a first
dedicated physical control channel (DPCCH).
3. The method of claim 1 wherein the second data stream includes a
second DPCCH.
4. The method of claim 1 wherein the pre-coding weights are
determined for closed loop transmit diversity.
5. The method of claim 1 wherein the first DPCCH and the second
DPCCH carry a same pilot sequence.
6. The method of claim 1 wherein the first DPCCH and the second
DPCCH are transmitted using different channelization codes.
7. A wireless transmit/receive unit (WTRU) for uplink transmission
using multiple antennas, the WTRU comprising: a physical layer
processing block configured to generate a first data stream and a
second data stream; a pre-coding block configured to multiply
pre-coding weights to first data stream and the second data stream
to generate a plurality of output streams; and a plurality of
antennas for transmitting the output streams.
8. The WTRU of claim 7 wherein the first data stream includes an
E-DCH dedicated physical data channel (E-DPDCH) and a first
dedicated physical control channel (DPCCH).
9. The WTRU of claim 7 wherein the second data stream includes a
second DPCCH.
10. The WTRU of claim 7 wherein the pre-coding weights are
determined for closed loop transmit diversity.
11. The WTRU of claim 7 wherein the first DPCCH and the second
DPCCH carry a same pilot sequence.
12. The WTRU of claim 7 wherein the first DPCCH and the DPCCH are
transmitted using different channelization codes.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 14/172,615, filed Feb. 4, 2014, which is a
continuation of U.S. patent application Ser. No. 13/718,177, filed
Dec. 18, 2012, which issued as U.S. Pat. No. 8,665,990 on Mar. 4,
2014, which is a continuation of U.S. patent application Ser. No.
12/894,556, filed Sep. 30, 2010, which issued as U.S. Pat. No.
8,355,424 on Jan. 15, 2013, which claims the benefit of U.S.
Provisional Application Nos. 61/247,123 filed Sep. 30, 2009;
61/248,313 filed Oct. 2, 2009; and 61/356,320 filed Jun. 18, 2010,
the contents of which are hereby incorporated by reference
herein.
BACKGROUND
[0002] Techniques for using multiple antennas have been used in
cellular wireless communication systems as an effective means to
improve robustness of data transmission and achieve higher data
throughput. One of the multiple antenna techniques is space-time
block coding (STBC). STBC is based on introducing joint
correlations in transmitted signals in both the space and time
domains to provide transmit diversity to combat fading
channels.
[0003] The Alamouti scheme is the space-time block code to provide
transmit diversity for systems with two transmit antennas. The
Alamouti-based space-time block code has been widely used because
of its simplicity and no need for the transmitter to know the
channel state information (CSI) and therefore no need of channel
feedback. Due to its effectiveness and easy implementation, the
Alamouti-based space-time block code has been adopted into many
wireless systems, such as WiMAX and WiFi. In third generation
partnership project (3GPP), it was introduced in downlink
transmissions in universal mobile telecommunication system (UMTS)
since Release 99 and also adopted in downlink high speed downlink
packet access (HSDPA) over higher speed data channels in Release 5.
In the 3GPP standard, the implementation of Alamouti scheme is
known as space time transmit diversity (STTD).
[0004] Enhanced uplink (EU), (also known as high speed uplink
packet access (HSUPA)), is a feature that was introduced in 3GPP
Release 6 to provide higher data rates in the uplink of UMTS
wireless systems. The HSUPA may be configured to allow for much
faster scheduling of uplink transmissions as well as lower overall
data transmission latency.
[0005] Multiple antenna transmission/reception techniques with
advanced signal processing are often referred to as multiple-input
multiple-output (MIMO). MIMO has been widely studied and may
significantly improve the performance of wireless communication
systems.
[0006] Multiple antenna techniques have been widely adopted in many
wireless communication systems such as IEEE 802.11n based wireless
local area network access points and cellular systems like wideband
code division multiple access (WCDMA)/high speed packet access
(HSPA) and long term evolution (LTE). MIMO is introduced in WiMAX
as well as in 3GPP. More advanced MIMO enhancements are currently
being studied for 3GPP Release 9 and 10. Currently, only downlink
(DL) MIMO is specified in 3GPP WCDMA standard.
SUMMARY
[0007] Method and apparatus for uplink transmission using multiple
antennas are disclosed. A wireless transmit/receive unit (WTRU)
performs space time transmit diversity (STTD) encoding on an input
stream of a physical channel configured for STTD. Each physical
channel may be mapped to either an in-phase (I) branch or a
quadrature-phase (Q) branch. The STTD encoding generates a
plurality of output streams such that the input stream is not
changed for one output stream, and symbols of the input stream is
switched and a constellation point of one symbol is changed to an
opposite constellation point on an I branch or a Q branch for the
other output stream. All configured physical channels on an I
branch and a Q branch are combined, respectively, to generate a
plurality of combined streams in a complex format, and the combined
streams are transmitted via a plurality of antennas.
[0008] The physical channel configured for STTD may include at
least one of an enhanced dedicated channel (E-DCH) dedicated
physical data channel (E-DPDCH), an E-DCH dedicated physical
control channel (E-DPCCH), a high speed dedicated physical control
channel (HS-DPCCH), a dedicated physical control channel (DPCCH),
and a dedicated physical data channel (DPDCH).
[0009] The WTRU may perform the STTD encoding either in a binary
domain or in a complex domain. For the complex domain STTD
encoding, the STTD encoding is performed on a block of
complex-valued chips corresponding to one or an integer multiple of
a largest spreading factor among the physical channels.
[0010] A WTRU may perform pre-coding on at least one type of uplink
physical channel including the E-DPDCH with the pre-coding weights,
and transmitting the pre-coded output streams via a plurality of
antennas. Either multiple E-DPDCH data streams may be transmitted
using multiple-input multiple-output (MIMO) or a single E-DPDCH
data stream may be transmitted using a closed loop transmit
diversity depending on the E-DPDCH configuration. The pre-coding
may be performed either after or before the spreading
operation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] A more detailed understanding may be had from the following
description, given by way of example in conjunction with the
accompanying drawings wherein:
[0012] FIG. 1A is a system diagram of an example communications
system in which one or more disclosed embodiments may be
implemented;
[0013] FIG. 1B is a system diagram of an example wireless
transmit/receive unit (WTRU) that may be used within the
communications system illustrated in FIG. 1A;
[0014] FIG. 1C is a system diagram of an example radio access
network and an example core network that may be used within the
communications system illustrated in FIG. 1A;
[0015] FIG. 2 shows an STTD transmitter in accordance with one
embodiment;
[0016] FIG. 3 shows an STTD transmitter in accordance with another
embodiment;
[0017] FIG. 4 shows an STTD transmitter in accordance with another
embodiment;
[0018] FIG. 5 shows an STTD transmitter in accordance with another
embodiment;
[0019] FIG. 6 shows an STTD transmitter in accordance with another
embodiment;
[0020] FIG. 7 shows an STTD transmitter in accordance with another
embodiment;
[0021] FIG. 8 shows an STTD transmitter in accordance with another
embodiment;
[0022] FIG. 9(A)-9(D) show transmission schemes for the non-STTD
channel(s);
[0023] FIGS. 10(A) and 10(B) show example binary STTD encoders for
binary phase shift keying (BPSK) modulated data transmission;
[0024] FIGS. 11(A) and 11(B) show example STTD encoders for 4-level
pulse amplitude modulation (4PAM) modulation;
[0025] FIGS. 12(A) and 12(B) show example STTD encoders for
8PAM;
[0026] FIG. 13 shows an example transmitter structure with a dual
binary STTD encoder;
[0027] FIG. 14 shows an example STTD transmitter with a complex
STTD encoder;
[0028] FIG. 15 shows an example complex STTD encoding process;
[0029] FIG. 16 shows STTD symbol configuration with different
spreading factors (SFs);
[0030] FIG. 17 illustrates an exemplary complex STTD encoding
applied to the HSUPA data channels;
[0031] FIG. 18 shows the corresponding block encoder in accordance
with this embodiment;
[0032] FIG. 19 shows an example transmitter in accordance with one
embodiment;
[0033] FIG. 20 shows an example transmitter in accordance with
another embodiment;
[0034] FIG. 21 shows an example transmitter in accordance with
another embodiment;
[0035] FIG. 22 shows an example transmitter in accordance with
another embodiment;
[0036] FIG. 23 shows an example transmitter in accordance with
another embodiment;
[0037] FIG. 24 shows an example transmitter in accordance with
another embodiment;
[0038] FIG. 25 shows an example transmitter in accordance with
another embodiment;
[0039] FIG. 26 shows the spreading operation, which includes
spreading with a given channelization code, weighting, and IQ phase
mapping;
[0040] FIG. 27 shows an example pre-coder for the dual stream
case;
[0041] FIG. 28 shows another example pre-coder for the dual stream
case;
[0042] FIG. 29 shows another example pre-coder for the dual stream
case;
[0043] FIG. 30 shows an example transmitter for the two stream
case;
[0044] FIG. 31A shows an example UPCI signaling using an
E-HICH;
[0045] FIG. 31B illustrates the case where one out of seven E-HICH
subframes carries the UPCI field;
[0046] FIG. 32 shows an example transmitter for transmitting uplink
precoding control information (UPCI) for two WTRUs via an E-DCH
channel state information channel (E-CSICH) in accordance with one
embodiment;
[0047] FIG. 33 shows another example transmitter for transmitting
UPCI for two WTRUs via an E-CSICH in accordance with another
embodiment;
[0048] FIG. 34 shows another example transmitter for transmitting
UPCI for two WTRUs via an E-CSICH in accordance with another
embodiment;
[0049] FIG. 35 shows an F-DPCH format in accordance with this
embodiment;
[0050] FIGS. 36 and 37 show signaling of PHI and POI using the
transmitter structure shown in FIGS. 32 and 34, respectively;
[0051] FIGS. 38 and 39 show signaling of UPCI and rank indication
(RI) using the transmitter structure shown in FIGS. 32 and 34,
respectively;
[0052] FIG. 40 shows an example frame format for the E-CSICH.
DETAILED DESCRIPTION
[0053] FIG. 1A is a diagram of an example communications system 100
in which one or more disclosed embodiments may be implemented. The
communications system 100 may be a multiple access system that
provides content, such as voice, data, video, messaging, broadcast,
etc., to multiple wireless users. The communications system 100 may
enable multiple wireless users to access such content through the
sharing of system resources, including wireless bandwidth. For
example, the communications systems 100 may employ one or more
channel access methods, such as code division multiple access
(CDMA), time division multiple access (TDMA), frequency division
multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier
FDMA (SC-FDMA), and the like.
[0054] As shown in FIG. 1A, the communications system 100 may
include wireless transmit/receive units (WTRUs) 102a, 102b, 102c,
102d, a radio access network (RAN) 104, a core network 106, a
public switched telephone network (PSTN) 108, the Internet 110, and
other networks 112, though it will be appreciated that the
disclosed embodiments contemplate any number of WTRUs, base
stations, networks, and/or network elements. Each of the WTRUs
102a, 102b, 102c, 102d may be any type of device configured to
operate and/or communicate in a wireless environment. By way of
example, the WTRUs 102a, 102b, 102c, 102d may be configured to
transmit and/or receive wireless signals and may include user
equipment (UE), a mobile station, a fixed or mobile subscriber
unit, a pager, a cellular telephone, a personal digital assistant
(PDA), a smartphone, a laptop, a netbook, a personal computer, a
wireless sensor, consumer electronics, and the like.
[0055] The communications systems 100 may also include a base
station 114a and a base station 114b. Each of the base stations
114a, 114b may be any type of device configured to wirelessly
interface with at least one of the WTRUs 102a, 102b, 102c, 102d to
facilitate access to one or more communication networks, such as
the core network 106, the Internet 110, and/or the networks 112. By
way of example, the base stations 114a, 114b may be a base
transceiver station (BTS), a Node-B, an eNode B, a Home Node B, a
Home eNode B, a site controller, an access point (AP), a wireless
router, and the like. While the base stations 114a, 114b are each
depicted as a single element, it will be appreciated that the base
stations 114a, 114b may include any number of interconnected base
stations and/or network elements.
[0056] The base station 114a may be part of the RAN 104, which may
also include other base stations and/or network elements (not
shown), such as a base station controller (BSC), a radio network
controller (RNC), relay nodes, etc. The base station 114a and/or
the base station 114b may be configured to transmit and/or receive
wireless signals within a particular geographic region, which may
be referred to as a cell (not shown). The cell may further be
divided into cell sectors. For example, the cell associated with
the base station 114a may be divided into three sectors. Thus, in
one embodiment, the base station 114a may include three
transceivers, i.e., one for each sector of the cell. In another
embodiment, the base station 114a may employ multiple-input
multiple output (MIMO) technology and, therefore, may utilize
multiple transceivers for each sector of the cell.
[0057] The base stations 114a, 114b may communicate with one or
more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116,
which may be any suitable wireless communication link (e.g., radio
frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible
light, etc.). The air interface 116 may be established using any
suitable radio access technology (RAT).
[0058] More specifically, as noted above, the communications system
100 may be a multiple access system and may employ one or more
channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA,
and the like. For example, the base station 114a in the RAN 104 and
the WTRUs 102a, 102b, 102c may implement a radio technology such as
Universal Mobile Telecommunications System (UMTS) Terrestrial Radio
Access (UTRA), which may establish the air interface 116 using
wideband CDMA (WCDMA). WCDMA may include communication protocols
such as High-Speed Packet Access (HSPA) and/or Evolved HSPA
(HSPA+). HSPA may include High-Speed Downlink Packet Access (HSDPA)
and/or High-Speed Uplink Packet Access (HSUPA).
[0059] In another embodiment, the base station 114a and the WTRUs
102a, 102b, 102c may implement a radio technology such as Evolved
UMTS Terrestrial Radio Access (E-UTRA), which may establish the air
interface 116 using Long Term Evolution (LTE) and/or LTE-Advanced
(LTE-A).
[0060] In other embodiments, the base station 114a and the WTRUs
102a, 102b, 102c may implement radio technologies such as IEEE
802.16 (i.e., Worldwide Interoperability for Microwave Access
(WiMAX)), CDMA2000, CDMA2000 1.times., CDMA2000 EV-DO, Interim
Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim
Standard 856 (IS-856), Global System for Mobile communications
(GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE
(GERAN), and the like.
[0061] The base station 114b in FIG. 1A may be a wireless router,
Home Node B, Home eNode B, or access point, for example, and may
utilize any suitable RAT for facilitating wireless connectivity in
a localized area, such as a place of business, a home, a vehicle, a
campus, and the like. In one embodiment, the base station 114b and
the WTRUs 102c, 102d may implement a radio technology such as IEEE
802.11 to establish a wireless local area network (WLAN). In
another embodiment, the base station 114b and the WTRUs 102c, 102d
may implement a radio technology such as IEEE 802.15 to establish a
wireless personal area network (WPAN). In yet another embodiment,
the base station 114b and the WTRUs 102c, 102d may utilize a
cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, etc.)
to establish a picocell or femtocell. As shown in FIG. 1A, the base
station 114b may have a direct connection to the Internet 110.
Thus, the base station 114b may not be required to access the
Internet 110 via the core network 106.
[0062] The RAN 104 may be in communication with the core network
106, which may be any type of network configured to provide voice,
data, applications, and/or voice over internet protocol (VoIP)
services to one or more of the WTRUs 102a, 102b, 102c, 102d. For
example, the core network 106 may provide call control, billing
services, mobile location-based services, pre-paid calling,
Internet connectivity, video distribution, etc., and/or perform
high-level security functions, such as user authentication.
Although not shown in FIG. 1A, it will be appreciated that the RAN
104 and/or the core network 106 may be in direct or indirect
communication with other RANs that employ the same RAT as the RAN
104 or a different RAT. For example, in addition to being connected
to the RAN 104, which may be utilizing an E-UTRA radio technology,
the core network 106 may also be in communication with another RAN
(not shown) employing a GSM radio technology.
[0063] The core network 106 may also serve as a gateway for the
WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet
110, and/or other networks 112. The PSTN 108 may include
circuit-switched telephone networks that provide plain old
telephone service (POTS). The Internet 110 may include a global
system of interconnected computer networks and devices that use
common communication protocols, such as the transmission control
protocol (TCP), user datagram protocol (UDP) and the internet
protocol (IP) in the TCP/IP internet protocol suite. The networks
112 may include wired or wireless communications networks owned
and/or operated by other service providers. For example, the
networks 112 may include another core network connected to one or
more RANs, which may employ the same RAT as the RAN 104 or a
different RAT.
[0064] Some or all of the WTRUs 102a, 102b, 102c, 102d in the
communications system 100 may include multi-mode capabilities,
i.e., the WTRUs 102a, 102b, 102c, 102d may include multiple
transceivers for communicating with different wireless networks
over different wireless links. For example, the WTRU 102c shown in
FIG. 1A may be configured to communicate with the base station
114a, which may employ a cellular-based radio technology, and with
the base station 114b, which may employ an IEEE 802 radio
technology.
[0065] FIG. 1B is a system diagram of an example WTRU 102. As shown
in FIG. 1B, the WTRU 102 may include a processor 118, a transceiver
120, a transmit/receive element 122, a speaker/microphone 124, a
keypad 126, a display/touchpad 128, non-removable memory 106,
removable memory 132, a power source 134, a global positioning
system (GPS) chipset 136, and other peripherals 138. It will be
appreciated that the WTRU 102 may include any sub-combination of
the foregoing elements while remaining consistent with an
embodiment.
[0066] The processor 118 may be a general purpose processor, a
special purpose processor, a conventional processor, a digital
signal processor (DSP), a plurality of microprocessors, one or more
microprocessors in association with a DSP core, a controller, a
microcontroller, Application Specific Integrated Circuits (ASICs),
Field Programmable Gate Array (FPGAs) circuits, any other type of
integrated circuit (IC), a state machine, and the like. The
processor 118 may perform signal coding, data processing, power
control, input/output processing, and/or any other functionality
that enables the WTRU 102 to operate in a wireless environment. The
processor 118 may be coupled to the transceiver 120, which may be
coupled to the transmit/receive element 122. While FIG. 1B depicts
the processor 118 and the transceiver 120 as separate components,
it will be appreciated that the processor 118 and the transceiver
120 may be integrated together in an electronic package or
chip.
[0067] The transmit/receive element 122 may be configured to
transmit signals to, or receive signals from, a base station (e.g.,
the base station 114a) over the air interface 116. For example, in
one embodiment, the transmit/receive element 122 may be an antenna
configured to transmit and/or receive RF signals. In another
embodiment, the transmit/receive element 122 may be an
emitter/detector configured to transmit and/or receive IR, UV, or
visible light signals, for example. In yet another embodiment, the
transmit/receive element 122 may be configured to transmit and
receive both RF and light signals. It will be appreciated that the
transmit/receive element 122 may be configured to transmit and/or
receive any combination of wireless signals.
[0068] In addition, although the transmit/receive element 122 is
depicted in FIG. 1B as a single element, the WTRU 102 may include
any number of transmit/receive elements 122. More specifically, the
WTRU 102 may employ MIMO technology. Thus, in one embodiment, the
WTRU 102 may include two or more transmit/receive elements 122
(e.g., multiple antennas) for transmitting and receiving wireless
signals over the air interface 116.
[0069] The transceiver 120 may be configured to modulate the
signals that are to be transmitted by the transmit/receive element
122 and to demodulate the signals that are received by the
transmit/receive element 122. As noted above, the WTRU 102 may have
multi-mode capabilities. Thus, the transceiver 120 may include
multiple transceivers for enabling the WTRU 102 to communicate via
multiple RATs, such as UTRA and IEEE 802.11, for example.
[0070] The processor 118 of the WTRU 102 may be coupled to, and may
receive user input data from, the speaker/microphone 124, the
keypad 126, and/or the display/touchpad 128 (e.g., a liquid crystal
display (LCD) display unit or organic light-emitting diode (OLED)
display unit). The processor 118 may also output user data to the
speaker/microphone 124, the keypad 126, and/or the display/touchpad
128. In addition, the processor 118 may access information from,
and store data in, any type of suitable memory, such as the
non-removable memory 106 and/or the removable memory 132. The
non-removable memory 106 may include random-access memory (RAM),
read-only memory (ROM), a hard disk, or any other type of memory
storage device. The removable memory 132 may include a subscriber
identity module (SIM) card, a memory stick, a secure digital (SD)
memory card, and the like. In other embodiments, the processor 118
may access information from, and store data in, memory that is not
physically located on the WTRU 102, such as on a server or a home
computer (not shown).
[0071] The processor 118 may receive power from the power source
134, and may be configured to distribute and/or control the power
to the other components in the WTRU 102. The power source 134 may
be any suitable device for powering the WTRU 102. For example, the
power source 134 may include one or more dry cell batteries (e.g.,
nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride
(NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, and
the like.
[0072] The processor 118 may also be coupled to the GPS chipset
136, which may be configured to provide location information (e.g.,
longitude and latitude) regarding the current location of the WTRU
102. In addition to, or in lieu of, the information from the GPS
chipset 136, the WTRU 102 may receive location information over the
air interface 116 from a base station (e.g., base stations 114a,
114b) and/or determine its location based on the timing of the
signals being received from two or more nearby base stations. It
will be appreciated that the WTRU 102 may acquire location
information by way of any suitable location-determination method
while remaining consistent with an embodiment.
[0073] The processor 118 may further be coupled to other
peripherals 138, which may include one or more software and/or
hardware modules that provide additional features, functionality
and/or wired or wireless connectivity. For example, the peripherals
138 may include an accelerometer, an e-compass, a satellite
transceiver, a digital camera (for photographs or video), a
universal serial bus (USB) port, a vibration device, a television
transceiver, a hands free headset, a Bluetooth.RTM. module, a
frequency modulated (FM) radio unit, a digital music player, a
media player, a video game player module, an Internet browser, and
the like.
[0074] FIG. 1C is a system diagram of the RAN 104 and the core
network 106 according to an embodiment. As noted above, the RAN 104
may employ a UTRA radio technology to communicate with the WTRUs
102a, 102b, 102c over the air interface 116. The RAN 104 may also
be in communication with the core network 106. As shown in FIG. 1C,
the RAN 104 may include Node-Bs 140a, 140b, 140c, which may each
include one or more transceivers for communicating with the WTRUs
102a, 102b, 102c over the air interface 116. The Node-Bs 140a,
140b, 140c may each be associated with a particular cell (not
shown) within the RAN 104. The RAN 104 may also include RNCs 142a,
142b. It will be appreciated that the RAN 104 may include any
number of Node-Bs and RNCs while remaining consistent with an
embodiment.
[0075] As shown in FIG. 1C, the Node-Bs 140a, 140b may be in
communication with the RNC 142a. Additionally, the Node-B 140c may
be in communication with the RNC142b. The Node-Bs 140a, 140b, 140c
may communicate with the respective RNCs 142a, 142b via an Iub
interface. The RNCs 142a, 142b may be in communication with one
another via an Iur interface. Each of the RNCs 142a, 142b may be
configured to control the respective Node-Bs 140a, 140b, 140c to
which it is connected. In addition, each of the RNCs 142a, 142b may
be configured to carry out or support other functionality, such as
outer loop power control, load control, admission control, packet
scheduling, handover control, macrodiversity, security functions,
data encryption, and the like.
[0076] The core network 106 shown in FIG. 1C may include a media
gateway (MGW) 144, a mobile switching center (MSC) 146, a serving
GPRS support node (SGSN) 148, and/or a gateway GPRS support node
(GGSN) 150. While each of the foregoing elements are depicted as
part of the core network 106, it will be appreciated that any one
of these elements may be owned and/or operated by an entity other
than the core network operator.
[0077] The RNC 142a in the RAN 104 may be connected to the MSC 146
in the core network 106 via an IuCS interface. The MSC 146 may be
connected to the MGW 144. The MSC 146 and the MGW 144 may provide
the WTRUs 102a, 102b, 102c with access to circuit-switched
networks, such as the PSTN 108, to facilitate communications
between the WTRUs 102a, 102b, 102c and traditional land-line
communications devices.
[0078] The RNC 142a in the RAN 104 may also be connected to the
SGSN 148 in the core network 106 via an IuPS interface. The SGSN
148 may be connected to the GGSN 150. The SGSN 148 and the GGSN 150
may provide the WTRUs 102a, 102b, 102c with access to
packet-switched networks, such as the Internet 110, to facilitate
communications between and the WTRUs 102a, 102b, 102c and
IP-enabled devices.
[0079] As noted above, the core network 106 may also be connected
to the networks 112, which may include other wired or wireless
networks that are owned and/or operated by other service
providers.
[0080] It should be noted that although the embodiments will be
described hereinafter in the context of 3GPP WCDMA, they are also
applicable to any other wireless communication systems including,
but not limited to, 3GPP LTE, LTE-Advanced, general packet radio
services (GPRS), CDMA2000, WiMAX, WiFi, IEEE 802.x systems, and the
like.
[0081] In 3GPP WCDMA, different uplink channels may be configured
for different purposes and applications. A dedicated physical
control channel (DPCCH) and a dedicated physical data channel
(DPDCH) are the control and data channels introduced in Release 99.
High speed downlink packet access (HSDPA) was introduced in Release
5, and a high speed dedicated physical control channel (HS-DPCCH)
serves as a control channel for the HSDPA services. The HS-DPCCH
carries channel quality indication and hybrid automatic repeat
request (HARQ) acknowledgement. In Release 6, enhanced dedicated
channel (E-DCH) services have been introduced. An E-DCH dedicated
physical control channel (E-DPCCH) and an E-DCH dedicated physical
data channel (E-DPDCH) are the control and data channels for E-DCH
services. The DPCCH is used to enable channel estimation at the
Node-Bs, to maintain a stable power control loop, and to provide
baseline reference for all other channels in terms of error rate
control and grant allocation.
[0082] The STTD encoding may be implemented with two or more
transmit antennas, each of which may be associated with its own
transmit chain including modulation mapper, spreader, I/Q
combining, scrambler, and separate radio frontend. Hereafter, the
embodiments will be explained with reference to the STTD
transmitter with two transmit antennas. However, it should be noted
that the embodiments may be extended to any number of transmit
antennas and to any type of spatial diversity or spatial
multiplexing multiple antenna transmission techniques.
[0083] The STTD encoder, as will be described in detail below,
performs space-time processing over the data stream or signal to be
transmitted and distributes its outputs to the two or more transmit
chains. After the STTD encoder, the signals operate independently
without interaction between the two or more transmit chains.
[0084] FIG. 2 shows an STTD transmitter 200 in accordance with one
embodiment. In accordance with this embodiment, the STTD encoding
may be applied to a high speed uplink data channel(s), (i.e., an
E-DPDCH), and it may not be applied to other channels. The STTD
transmitter 200 comprises a first physical layer processing block
202, an STTD processing block 204, second physical layer processing
blocks 206, third physical layer processing blocks 208, channel
combiners 210, and scramblers 212.
[0085] The first, second, and third physical layer processing
blocks 202, 206, 208 may perform the conventional signal processing
functions including modulation mapping, channelization code
spreading, gain scaling, and I/Q combining, or any other functions.
FIG. 2 shows that the STTD processing block 204 is placed between
the first and second physical processing blocks 202, 206, but the
STTD processing block 204 may be placed at any stage of the
physical layer processing, and the functions performed by the first
and second physical layer processing blocks 202, 206 may be
configured differently.
[0086] One or more E-DPDCHs may be configured for a WTRU. The
E-DPDCH(s) is processed by the first physical layer processing
block 202 and then processed by the STTD processing block 204. The
STTD processing block 204 outputs two or more signal streams
depending on the number of transmit antennas. The STTD processing
block 204 performs either binary STTD encoding or complex STTD
encoding, and may perform the STTD encoding either on a bit/symbol
level or on a block level, which will be explained in detail below.
If multiple E-DPDCHs are configured, multiple E-DPDCHs may be
processed individually or jointly depending on the STTD encoder
structure. The physical channels, (i.e., E-DPDCHs), are initially
formed as real valued and each physical channel may be mapped to
either I branch or Q branch. At I/Q combining stage in the physical
layer processing block (either the first physical layer processing
block 202 or the second physical layer processing block 206), the
physical channels mapped to either the I branch or the Q branch to
form complex signals. Non-STTD channels are processed by the third
physical layer processing block(s) 208. Which non-STTD channel is
mapped to which transmit antenna is explained in detail below. The
channel combining block 210 on each transmit path merges the signal
streams from all the channels mapped to the corresponding antenna
including the non-STTD channels and E-DPDCHs into a complex signal.
The channel combined signal streams are then scrambled by
scramblers 212 and transmitted via the antennas.
[0087] FIG. 3 shows an STTD transmitter 300 in accordance with
another embodiment. In accordance with this embodiment, the STTD
encoding is performed on HSUPA channels, (i.e., an E-DPDCH(s) and
an E-DPCCH), and it may not be applied to other channels. The STTD
transmitter 300 comprises first physical layer processing blocks
302a, 302b, STTD processing blocks 304a, 304b, second physical
layer processing blocks 306a, 306b, third physical layer processing
blocks 308, channel combiners 310, and scramblers 312.
[0088] The first, second, and third physical layer processing
blocks 302a/302b, 306a, 306b, 308 may perform the conventional
signal processing functions including modulation mapping,
channelization code spreading, gain scaling, and I/Q combining, or
any other functions. FIG. 3 shows that the STTD processing blocks
304a/304b are placed between the first and second physical
processing blocks 302a/302b and 306a/306b, but the STTD processing
blocks 304a/304b may be placed at any stage of the physical layer
processing, and the functions performed by the first and second
physical layer processing blocks 302a/302b, 306a/306b may be
configured differently.
[0089] The E-DPCCH is processed by the first physical layer
processing block 302a and then processed by the STTD processing
block 304a. One or more E-DPDCHs may be configured for a WTRU. The
E-DPDCH(s) is processed by the first physical layer processing
block 302b and then processed by the STTD processing block 304b.
Each of the STTD processing blocks 304a/304b outputs two or more
signal streams depending on the number of transmit antennas. The
STTD processing blocks 304a/304b perform either binary STTD
encoding or complex STTD encoding, and may perform the STTD
encoding either on a bit/symbol level or on a block level, which
will be explained in detail below. If multiple E-DPDCHs are
configured, multiple E-DPDCHs may be processed individually or
jointly depending on the STTD encoder structure. The physical
channels, (i.e., E-DPDCHs, E-DPCCH), are initially formed as real
valued and each physical channel may be mapped to either I branch
or Q branch. At I/Q combining stage in the physical layer
processing block (either the first physical layer processing block
302a/302b or the second physical layer processing block 306a/306b),
the physical channels are mapped to either the I branch or the Q
branch to form complex signals. Non-STTD channels are processed by
the third physical layer processing block(s) 308. The channel
combining block 310 on each transmit path merges the signal streams
from all the channels mapped to the corresponding antenna including
the non-STTD channels, E-DPDCHs, and E-DPCCH into a complex signal.
The channel combined signal streams are then scrambled by
scramblers 312 and transmitted via the antennas.
[0090] With the STTD transmitter of FIG. 3, the reliability of the
E-DPCCH associated with the high speed data channel is improved
correspondingly by the transmit diversity. Thus, user throughput at
cell edge will be enhanced without imposing the need of increasing
the transmit power of the control channel. This may allow the
E-DPCCH to have similar level of reliability with respect to the
E-DPDCH.
[0091] FIG. 4 shows an STTD transmitter in accordance with another
embodiment. In accordance with this embodiment, the STTD encoding
is performed on the uplink control channels, (i.e., a DPCCH, an
E-DPCCH, and an HS-DPCCH), and it may not be applied to other
channels. The STTD transmitter 400 comprises first physical layer
processing blocks 402a, 402b, 402c, STTD processing blocks 404a,
404b, 404c, second physical layer processing blocks 406a, 406b,
406c, third physical layer processing blocks 408, channel combiners
410, and scramblers 412.
[0092] The first, second, and third physical layer processing
blocks 402a, 402b, 402c, 406a, 406b, 406c, 408 may perform the
conventional signal processing functions including modulation
mapping, channelization code spreading, gain scaling, and I/Q
combining, or any other functions. FIG. 4 shows that the STTD
processing blocks 404a/404b/404c are placed between the first and
second physical processing blocks 402a/402b/402c and
406a/406b/406c, but the STTD processing block 404a, 404b, 404c may
be placed at any stage of the physical layer processing, and the
functions performed by the first and second physical layer
processing blocks 402a/402b/402c, 406a/406b/406c may be configured
differently.
[0093] The HS-DPCCH is processed by the first physical layer
processing block 402a and then processed by the STTD processing
block 404a. The DPCCH is processed by the first physical layer
processing block 402b and then processed by the STTD processing
block 404b. The DPCCH carries pilot symbols. Therefore, in
accordance with this embodiment, the pilot symbols are also STTD
encoded. The E-DPCCH is processed by the first physical layer
processing block 402c and then processed by the STTD processing
block 404c. Each of the STTD processing blocks 404a/404b/404c
outputs two or more signal streams depending on the number of
transmit antennas. The STTD processing blocks 404a/404b/404c
perform either binary STTD encoding or complex STTD encoding, and
may perform the STTD encoding either on a bit/symbol level or on a
block level, which will be explained in detail below. The physical
channels, (i.e., E-DPCCH, DPCCH, HS-DPCCH), are initially formed as
real valued and each physical channel may be mapped to either I
branch or Q branch. At I/Q combining stage in the physical layer
processing block (either the first physical layer processing block
402a/402b/402c or the second physical layer processing block
406a/406b/406c), the physical channels are mapped to either the I
branch or the Q branch to form complex signals. Non-STTD channels
are processed by the third physical layer processing block(s) 408.
The channel combining block 410 on each transmit path merges the
signal streams from all the channels mapped to the corresponding
antenna including the non-STTD channels, E-DPCCH, DPCCH, and
HS-DPCCH into a complex signal. The channel combined signal streams
are then scrambled by scramblers 412 and transmitted via the
antennas.
[0094] FIG. 5 shows an STTD transmitter 500 in accordance with
another embodiment. In accordance with this embodiment, the STTD
encoding is performed on data channels, (i.e., a DPDCH(s), an
E-DPDCH(s)), and it may not be applied to other channels. The STTD
transmitter 500 comprises first physical layer processing blocks
502a, 502b, STTD processing blocks 504a, 504b, second physical
layer processing blocks 506a, 506b, third physical layer processing
blocks 508, channel combiners 510, and scramblers 512.
[0095] The first, second, and third physical layer processing
blocks 502a, 502b, 506a, 506b, 508 may perform the conventional
signal processing functions including modulation mapping,
channelization code spreading, gain scaling, and I/Q combining, or
any other functions. FIG. 5 shows that the STTD processing blocks
504a/504b are placed between the first and second physical
processing blocks 502a/502b and 506a/506b, but the STTD processing
blocks 504a/504b may be placed at any stage of the physical layer
processing, and the functions performed by the first and second
physical layer processing blocks 502a/502b, 506a/506b may be
configured differently.
[0096] One or more DPDCH and/or one or more E-DPDCH(s) may be
configured for a WTRU. The DPDCH(s) is processed by the first
physical layer processing block 402a and then processed by the STTD
processing block 404a. The E-DPDCH(s) is processed by the first
physical layer processing block 402b and then processed by the STTD
processing block 404b. Each of the STTD processing blocks 404a/404b
outputs two or more signal streams depending on the number of
transmit antennas. The STTD processing blocks 404a/404b perform
either binary STTD encoding or complex STTD encoding, and may
perform the STTD encoding either on a bit/symbol level or on a
block level, which will be explained in detail below. If multiple
DPDCHs and/or E-DPDCHs are configured, multiple DPDCHs and/or
E-DPDCHs may be processed individually or jointly depending on the
STTD encoder structure. The physical channels, (i.e., DPDCH(s) and
E-DPDCH(s)), are initially formed as real valued and each physical
channel may be mapped to either I branch or Q branch. At I/Q
combining stage in the physical layer processing block (either the
first physical layer processing block 502a/502b or the second
physical layer processing block 506a/506b), the physical channels
are mapped to either the I branch or the Q branch to form complex
signals. Non-STTD channels are processed by the third physical
layer processing block(s) 508. The channel combining block 510 on
each transmit path merges the signal streams from all the channels
mapped to the corresponding antenna including the non-STTD
channels, DPDCH(s), and E-DPDCHs into a complex signal. The channel
combined signal streams are then scrambled by scramblers 512 and
transmitted via the antennas.
[0097] FIG. 6 shows an STTD transmitter 600 in accordance with
another embodiment. In accordance with this embodiment, STTD
encoding is performed on all uplink channels, (E-DPDCH(s), E-DPCCH,
DPDCH(s), DPCCH, HS-DPCCH). The STTD transmitter 600 comprises
first physical layer processing blocks 602a, 602b, 602c, 602d,
602e, STTD processing blocks 604a, 604b, 604c, 604d, 604e, second
physical layer processing blocks 606a, 606b, 606c, 606d, 606e,
channel combiners 610, and scramblers 612.
[0098] The first, second, and third physical layer processing
blocks 602a, 602b, 602c, 602d, 602e, 606a, 606b, 606c, 606d, 606e,
608 may perform the conventional signal processing functions
including modulation mapping, channelization code spreading, gain
scaling, and I/Q combining, or any other functions. FIG. 6 shows
that the STTD processing blocks 604a/604b/604c/606d/606e are placed
between the first and second physical processing blocks
602a/602b/602c/602d/602e and 606a/606b/606c/606d/606e, but the STTD
processing block 604a, 604b, 604c, 604d, 604e may be placed at any
stage of the physical layer processing, and the functions performed
by the first and second physical layer processing blocks
602a/602b/602c/602d/602e, 606a/606b/606c/606d/606e may be
configured differently.
[0099] The E-DPCCH is processed by the first physical layer
processing block 602a and then processed by the STTD processing
block 604a. One or more DPDCH and/or one or more E-DPDCH(s) may be
configured for a WTRU. The E-DPDCH(s) is processed by the first
physical layer processing block 602b and then processed by the STTD
processing block 604b. The DPCCH is processed by the first physical
layer processing block 602c and then processed by the STTD
processing block 604c. The DPCCH carries pilot symbols. Therefore,
in accordance with this embodiment, the pilot symbols are also STTD
encoded. The DPDCH(s) is processed by the first physical layer
processing block 602d and then processed by the STTD processing
block 604d. The HS-DPCCH is processed by the first physical layer
processing block 602e and then processed by the STTD processing
block 604e. Each of the STTD processing blocks
604a/604b/604c/604d/604e outputs two or more signal streams
depending on the number of transmit antennas. The STTD processing
blocks 604a/604b/604c/604d/604e perform either binary STTD encoding
or complex STTD encoding, and may perform the STTD encoding either
on a bit/symbol level or on a block level, which will be explained
in detail below. The physical channels, (i.e., E-DPCCH, DPCCH,
HS-DPCCH), are initially formed as real valued and each physical
channel may be mapped to either I branch or Q branch. At I/Q
combining stage in the physical layer processing block (either the
first physical layer processing block 602a/602b/602c/602d/602e or
the second physical layer processing block
606a/606b/606c/606d/606e), the physical channels are mapped to
either the I branch or the Q branch to form complex signals. The
channel combining block 610 on each transmit path merges the signal
streams from all the channels mapped to the corresponding antenna
including E-DPCCH, E-DPDCH(s), DPCCH, DPDCH(s), and HS-DPCCH into a
complex signal. The channel combined signal streams are then
scrambled by scramblers 612 and transmitted via the antennas.
[0100] The advantage of the STTD transmitter in FIG. 6 is that
channels (both data and control channels) are all balanced in terms
of the service quality therefore the power scaling configuration on
each channel may be maintained the same as if no STTD is applied as
long as the power control is performed properly according to the
specified signal-to-interference ratio (SIR) or block error rate
(BLER) target. Since the pilot signal transmitted in the DPCCH over
the two antennas may be made orthogonal at the receiver with the
appropriate STTD processing, the channel estimation at the Node-B
may be readily conducted without introducing the second pilot
signal.
[0101] The peak-to-average power ratio (PAPR) or the cubic metric
of all the STTD transmitter structures disclosed above may maintain
the similar level at each antenna as the conventional uplink
implementation, since the STTD processing is applied per data
symbol basis that does not introduce dependency between symbols
across time. This behavior may be understood by the fact that the
STTD processing may be implemented in binary or symbol domain (as
opposed to the chip domain) as shown below.
[0102] FIG. 7 shows an STTD transmitter in accordance with another
embodiment. In this embodiment, all channels except the DPCCH are
STTD processed. Because the pilot signal is embedded in the DPCCH,
this structure may offer the benefit of not requiring significant
modification of the channel estimation at the Node-B receiver side.
The STTD transmitter in FIG. 7 is substantially similar to the STTD
transmitter in FIG. 6. Therefore, it will not be explained in
detail for simplicity.
[0103] FIG. 8 shows an STTD transmitter in accordance with another
embodiment. In this embodiment, E-DPCCH, E-DPDCH(s), and HS-DPCCH
are STTD encoded and DPDCH(s) and DPCCH are not STTD encoded. With
this embodiment, the modification requirement at the Node-B
receiver may be reduced. The STTD transmitter in FIG. 7 is
substantially similar to the STTD transmitter in FIG. 6. Therefore,
it will not be explained in detail for simplicity.
[0104] The channels over which the STTD processing is not applied
may be transmitted over at least one antenna. The non-STTD
channel(s) may be transmitted over one of the antennas, as shown in
FIG. 9(A). Alternatively, the identical signals of the non-STTD
channel(s) may be transmitted over the two (or all) antennas, as
shown in FIG. 9(B). Alternately, the non-STTD channel(s) may be
transmitted over two (or all) antennas in a time division duplex
fashion in accordance with a configured pattern, as shown in FIG.
9(C). Alternatively, any types of space time processing or
multiple-input multiple-output (MIMO) schemes may be used for
transmission of the non-STTD channel(s), as illustrated in FIG.
9(D).
[0105] Different from the downlink in a UMTS communication system,
the physical channels in the uplink are formed as real-valued
sequences and fed into either the I branch or the Q branch of the
complex channel independently. Each of the physical channels is
spread and weighted by its own channelization code and gain factor.
As a result, the complex signal generated in such way may not have
the properties of a true two dimension constellation. It may
exhibit imbalance in phase and amplitude between its I-phase and
Q-phase components. Before sending to the radio front end, a
complex scrambler may be applied, and this helps to even out the
imbalance existing in the transmitted signal.
[0106] Embodiments for STTD encoder are disclosed hereafter. The
STTD encoder may be a binary STTD encoder or a complex STTD
encoder.
[0107] The binary STTD encoder operates in binary domain before the
physical layer processing, (i.e., prior to the modulation mapping).
Assuming b.sub.i, i=0, 1, 2, . . . , N where N is the number of
bits per symbol, are the bits to be transmitted, the STTD encoder
manipulates these bits to generate the inputs to create diversity
for the two (or more) separated antenna paths. Each channel may
form real-valued information sequence independently, and the
physical channels that may be placed on the I and Q branches
separately may be treated by a different STTD encoder. The STTD
encoding may then be performed separately for each I and Q branch.
FIGS. 10(A) and 10(B) show example binary STTD encoders for binary
phase shift keying (BPSK) modulated data transmission. One of them
may be used for an I-branch channel and the other may be used for a
Q branch channel. Each branch may use a different binary STTD
encoder. The input bit b.sub.i may take three values 0, 1, and
discontinues transmission (DTX). b.sub.i is defined as follows: if
b.sub.i=0 then b.sub.i=1, if b.sub.i=1 then b.sub.i=0, otherwise
b.sub.i=b.sub.i.
[0108] The dual binary STTD encoder configuration may vary
depending on the size of modulation mapping. FIGS. 11(A) and 11(B)
show example STTD encoders with example constellation mapping rules
for each branch for 4-level pulse amplitude modulation (4PAM)
modulation. One of them may be used for an I-branch channel and the
other may be used for a Q-branch channel.
[0109] The dual binary STTD encoder may be extended to other
constellations of any order. For example, constellation mapping
rules for the STTD encoding in general may be as follows: (1) the
data bits are taken for two consecutive symbols: b.sub.0b.sub.1 . .
. b.sub.N-1b.sub.N . . . b.sub.2N-1, where N is the number of bits
in a symbol, (2) the binary data for antenna 1 remains unchanged,
(3) the order of two symbols is changed as follows to generate the
data for antenna 2: b.sub.0b.sub.1 . . . b.sub.N-1b.sub.N . . .
b.sub.2N-1.fwdarw.b.sub.N . . . b.sub.2N-1b.sub.0b.sub.1 . . .
b.sub.N-1, and (4) a constellation mapping rule is applied for the
I-branch channels, whereby the first bit of the second symbol is
inverted: b.sub.N.fwdarw. b.sub.N, and for the Q-branch channels,
whereby the first bit of the first symbol is inverted:
b.sub.0.fwdarw. b.sub.0 (alternatively, different bit position may
be inverted depending on the constellation mapping rule).
[0110] FIGS. 12(A) and 12(B) show example STTD encoders with
constellation mapping rules for 8PAM. One of them may be used for
an I-branch channel and the other may be used for a Q-branch
channel.
[0111] FIG. 13 shows an example transmitter 1300 with a dual binary
STTD encoder. The transmitter 1300 includes STTD encoders 1302,
modulation mappers 1304, spreading blocks 1306, gain control blocks
1308, channel combining blocks 1310, I/Q combining blocks 1312, and
scrambling blocks 1314. Each channel may be processed individually
by the STTD encoder 1302. Each STTD processing block 1302 outputs
two or more signal streams depending on the number of transmit
antennas. Each signal stream from the STTD encoder 1302 is then
processed by a modulation mapper 1304, and then by a spreading
block 1306, and a gain control block 1308 with its own
channelization code and gain factor. The channel combining block
1310 and the I/Q combining block 1312 merge all the channels into a
complex signal, which is scrambled by a scrambling block 1314
before transmitted over the assigned antenna. Since it is
implemented in the binary domain, the dual binary STTD encoder 1302
offers a simple solution that allows an implementation to duplicate
two transmit chains, one for each antenna, without having to make
much modification as compared to the conventional WTRU transmitter
structure.
[0112] Since the symbol boundaries of all considered physical
channels, (i.e., DPCCH, DPDCH, E-DPCCH, E-DPDCH, and HS-DPCCH), are
aligned at certain time point, the STTD encoding may be performed
in a complex domain. Due to the fact that each channel is spread in
real domain and the complex signal comprises multiple channels, the
STTD encoder should deal with different symbol durations resulted
from different spreading factors (SFs) among the channels as shown
in the Table 1.
TABLE-US-00001 TABLE 1 Physical channel type SF Symbols/slot DPCCH
256 10 DPDCH 2, 4, 8, . . . , 256 10, . . . , 1280 HS-DPCCH 256 10
E-DPCCH 256 10 E-DPDCH 2, 4, 8, . . . , 256 10, . . . , 1280
[0113] FIG. 14 shows an example STTD transmitter 1400 with a
complex STTD encoder. The transmitter 1400 comprises modulation
mappers 1402a, 1402b, spreading blocks 1404a, 1404b, gain control
blocks 1406a, 1406b, channel and I/Q combining blocks 1408a, 1408b,
a complex STTD encoder 1410, channel combining blocks 1412, and
scrambling blocks 1414. STTD channels are processed by a modulation
mapper 1402a, a spreading block 1404a, and a gain control block
1406a, and combined into a complex signal by the channel and I/Q
combining block 1408a. The combined STTD channel signals are then
processed by the complex STTD encoder 1410. Non-STTD channels are
processed by a modulation mapper 1402b, a spreading block 1404b,
and a gain control block 1406b, and combined into a complex signal
by the channel and I/Q combining block 1408b. The STTD-encoded STTD
channel signals and the processed non-STTD channel signals are then
combined by the channel combiners 1412, and then processed by the
respective scrambling blocks 1414 for transmission.
[0114] FIG. 15 shows an example complex STTD encoding process. It
should be noted that the complex STTD encoding may be performed
with any STTD transmitters disclosed above. The uplink channels
(DPCCH, DPDCH(s), HS-DPCCH, E-DPCCH, E-DPDCH(s)) are spread by a
specific spreading block 1502 with a specific channelization code
with a specific spreading factor and combined to a complex signal
by a combiner 1504. The spreading factors for the uplink channels
may be different. The combined complex signal 1505, (i.e., a block
of chips combined over multiple uplink channels, which will be
referred to as "STTD symbol"), is scrambled by the scrambler 1506
and stored in buffers 1508a, 1508b in time alternation, (i.e., the
switch 1507 switches every T time instant), so that two consecutive
STTD symbols are processed by the STTD encoder 1510 for STTD
encoding.
[0115] The switch 1507 is synchronized to a symbol boundary as
follows. Over the complex signal, the STTD symbols are defined such
that a symbol duration "T" equals to the length of data symbols
from the channel with a largest spreading factor of value
SF.sub.max, and the time boundary is aligned with the data symbols
from the channel with the largest spreading factor of value
SF.sub.max. Therefore, each STTD symbol comprises SF.sub.max chips.
The complex STTD operation is then performed over the STTD symbols
S0 and S1 as follows:
[ s 0 s 1 ] [ s 0 s 1 - s 1 * s 0 * ] ; Equation ( 1 )
##EQU00001##
where * represents a complex conjugate. The complex conjugate and
negative operations are performed over the whole waveform of the
STTD symbols, or equivalently, over every chip of the spread
complex signal. The matrix notation means that S.sub.0 is
transmitted first in its entirety and then followed by S.sub.1 in
its entirety at the first antenna, and -S.sub.1* is transmitted
first in its entirety and then followed by S.sub.0* in its entirety
at the second antenna. The receiver needs be aware of the symbol
configuration and boundary to perform decoding.
[0116] FIG. 16 shows an example STTD symbol configuration for
channels with different SFs, where each of the STTD symbols
(S.sub.0 or S.sub.1) contains S.sub.SFmax chips. The channels may
take any combination of SFs in any order. Channel 1 is spread with
the largest SF (SF.sub.max), and the STTD symbol of that channel
contains one symbol of S.sub.SFmax chips. Channel 2 is spread with
a half of the SF., (i.e., SF.sub.max/2), and the STTD symbols of
that channel contains two symbols, each comprising S.sub.SFmax/2
chips. Channel N is spread with SF.sub.max/k, and the STTD symbols
of that channel contains k symbols, each comprising S.sub.SFmax/k
chips. More than one channel may be spread with the same spreading
factor and some spreading factors may not be used. For the channels
that have spreading factor equal to SF.sub.max, one information
symbol is transmitted in an STTD symbol. The other channels may
have more than one information symbols included in an STTD symbol,
depending on the spreading factor. As shown in FIG. 16, the number
of data symbols contained in an STTD symbol for a particular
channel is determined by the ratio of SF.sub.max and SF associated
to that channel. For example, if a channel is spread with a
spreading factor SF.sub.max/2, then the channel may have two data
symbols per STTD symbol.
[0117] An exemplary complex STTD encoding applied to the high speed
uplink packet access (HSUPA) data channels, (i.e., the E-DPDCHs),
is illustrated hereafter with reference to FIG. 17. FIG. 17 shows
an example transmitter 1700 with a complex STTD encoder for
transmission of four E-DPDCHs. The transmitter 1700 comprises
modulation mappers 1702, channelization blocks 1704, gain control
blocks 1706, channel combiners 1708, an I/Q combiner 1710, and an
STTD encoder 1712. In this example, the WTRU transmits at a peak
uplink data rate, where four E-DPDCHs are configured for uplink
data transmission allowing a total of 11.5 Mbps of data throughput.
The channelization codes and spreading factors used for these
E-DPDCHs are specified in Table 2.
TABLE-US-00002 TABLE 2 E-DPDCH Channelization Spreading I/Q
channels codes factor path E-DPDCH1 C.sub.2,1 2 I E-DPDCH2
C.sub.2,1 2 Q E-DPDCH3 C.sub.4,1 4 I E-DPDCH4 C.sub.4,1 4 Q
[0118] In this example, E-DPDCHs 1 and 3 are mapped to I branch,
and E-DPDCHs 2 and 4 are mapped to Q branch. The binary streams on
each E-DPDCH are mapped to 4PAM symbols individually by the
modulation mapper 1702. Each of the E-DPDCHs is spread with a
corresponding channelization code by the channelization block 1704
and then scaled with a corresponding gain factor by the gain
control block 1706. The E-DPDCHs may take different spreading
factors, (i.e., 2 and 4 in this example). The outputs of the
processing for each of the E-DPDCHs are the chips denoted by
x.sub.1(n), x.sub.2(n), x.sub.3(n), x.sub.4(n), where n is the chip
index.
[0119] E-DPDCHs 1 and 3 and E-DPDCHs 2 and 4 are then combined by
the channel combining blocks 1708, respectively, and then combined
to a complex signal by the I/Q combining block 1710. Combining the
channels according to the I/Q path assignment listed in Table 2
yields:
x(n)=x.sub.1(n)+jx.sub.2(n)+x.sub.3(n)+jx.sub.4(n). Equation
(2)
[0120] After the complex STTD encoding by the STTD encoder 1712,
the first STTD symbol (even symbol) contains the following four
chips:
s.sub.0={x(0),x(1),x(2),x(3)}; Equation (3)
and the second STTD symbol (odd symbol) contains the following four
chips:
s.sub.1={x(4),x(5),x(6),x(7)}. Equation (4)
[0121] At antenna 1, S.sub.0 is transmitted first and followed by
S.sub.1, and at antenna 2, --S.sub.1* is transmitted first and then
followed by S.sub.0*. The same procedure is repeated for the even
and odd STTD symbols.
[0122] The complex STTD encoding above may be extended to a longer
symbol period. The STTD symbol may contain more than one data
symbol corresponding to the largest SF, which may allow longer
diversity coherence time to combat slow fading channels. The value
"T" in FIG. 15, for example, may take an integer multiple of
SF.sub.max chips. FIG. 18 shows a block STTD encoder in accordance
with one embodiment. FIG. 18 shows that the STTD symbol comprises
more than one data symbol of S.sub.SFmax chips. More than one
channel may be mapped to the same spreading factor. The complex
STTD encoder may offer better time diversity and the cubic metric
of second antenna may be less affected. This embodiment may be
extended to the dual binary STTD encoder described above with more
bits in one symbol.
[0123] Embodiments for multi-antenna transmission schemes with
pre-coding in the uplink are disclosed hereafter.
[0124] In HSUPA, UL physical layer comprises multiple dedicated
physical channels, including control channels, such as DPCCH,
E-DPCCH and HS-DPCCH, and data channels, such as DPDCH and E-DPDCH.
When a WTRU is configured in a UL MIMO mode, the WTRU performs
E-DCH transport format combination (E-TFC) selection to schedule
one or more transport blocks in every TTI. When only one transport
block is scheduled, it may be mapped to the primary transport
block.
[0125] Hereinafter, the following terminologies will be used.
E-DPDCH1 and E-DPDCH2 are two sets of E-DPDCHs mapped to the
primary and secondary E-DCH data stream, which may also be referred
to as primary and secondary stream. E-DPDCH1 and E-DPDCH2 may
comprise one or more E-DPDCHs. E-DPDCH1.sub.k denotes the k.sup.th
physical E-DPDCH of the primary E-DCH data stream, and
E-DPDCH2.sub.k denotes the k.sup.th physical E-DPDCH of the
secondary E-DCH data stream. DPDCH1 and DPDCH2 are two set of
DPDCHs mapped to the primary and secondary DPDCH data stream,
respectively. DPDCH1.sub.n denotes the n.sup.th physical DPDCH of
the primary DPDCH data stream, where n=0, . . . , N.sub.max-dpdch1.
DPDCH2.sub.n denotes the n.sup.th physical DPDCH of the secondary
DPDCH data stream, where n=0, . . . , N.sub.max-dpdch2. It should
be noted that the embodiments disclosed herein are mainly described
with reference to dual-E-DCH stream transmission, (i.e., both the
primary E-DCH data stream and the secondary E-DCH data stream), but
the embodiments are equally applicable to a single E-DCH stream
transmission.
[0126] The transmitter embodiments disclosed below show pre-coding
for the dual-stream transmission, (i.e., two transport blocks:
primary and secondary transport blocks). It should be noted that
all the transmitter embodiments disclosed below may operate with a
single stream or multiple streams. If a single stream needs to be
transmitted, one transmit chain in the transmitter is utilized for
transmission of the single stream. If dual stream is configured,
primary and secondary E-DCH transport blocks pass through the
transport channel (TrCH) processing for E-DCH which may include
adding cyclic redundancy check (CRC) parity bits to the transport
block, code block segmentation, channel coding, physical layer
hybrid automatic repeat request (HARQ), rate matching, physical
channel segmentation, interleaving and mapping to E-DPDCH1 and
E-DPDCH2, and the like. When only one transport block is scheduled,
it may be mapped to the primary transport block, using one signal
chain.
[0127] FIG. 19 shows an example transmitter 1900 in accordance with
one embodiment. In this embodiment, the transmitter 1900 applies
pre-coding operation to both E-DPCCH and E-DPDCH after spreading
operations. By applying the same precoding weights to both the
E-DPDCH and the E-DPCCH of the same stream, both the E-DPDCH and
the E-DPCCH may experience similar propagation conditions. As a
result, the conventional power setting rules for the E-DPCCH and
the E-DPDCH may be re-used.
[0128] The transmitter 1900 comprises physical layer processing
blocks 1902 for E-DPDCH, spreading blocks 1904, 1906, 1914,
combining blocks 1908, 1916, a precoder 1910, a weights selection
block 1912, scramblers 1918, filters 1920, and antennas 1922.
Primary and secondary E-DCH transport blocks, if dual-stream is
configured, (or a primary E-DCH transport block if one stream is
configured), are processed by the physical layer processing blocks
1902 for E-DPDCH. The physical layer processing may include adding
CRC parity bits to the transport block, code block segmentation,
channel coding, physical layer HARQ, rate matching, physical
channel segmentation, interleaving and mapping to E-DPDCH1 and
E-DPDCH2 if dual-stream is configured, respectively, (or to
E-DPDCH1 if a single stream is configured). Either E-DPDCH1 or
E-DPDCH2 may comprise one or more E-DPDCHs depending on the E-TFCI
selected for the primary and secondary E-DCH transport blocks,
which may or may not be the same.
[0129] After the physical layer processing, the data streams on the
E-DPDCH1 and the E-DPDCH2 are spread by the spreading blocks 1904,
respectively. Spreading operations on the E-DPCCH1 and the E-DPCCH2
are also performed by the spreading blocks 1906. The E-DPCCH2 is
present if there are two E-DCH transport blocks being transmitted.
In case where a single E-DCH stream is transmitted, the E-DPCCH2
may not be transmitted. After the spreading operation, the
real-valued chips on the I and Q branches of the E-DPDCH(s) and the
E-DPCCH(s) are summed by the combiners 1908 into two complex-valued
streams. The two complex-valued streams are then processed by the
pre-coder 1910. The pre-coder 1910 applies pre-coding weights
determined by the weights selection block 1912 to distribute the
signals to the antennas 1922. Depending on the number of transport
blocks scheduled for transmission, the weights selection block 1912
may provide one or more sets of pre-coder weights. The pre-coding
operation will be explained in detail below.
[0130] For every pre-defined or configured period, (e.g., every TTI
or slot), the pre-coder weights may be updated for the upcoming
transmission. Based on the channel-dependent feedback information
from the Node-B, the weights selection block 1912 may select the
pre-coding weights, which will be explained in detail below.
[0131] After the precoding, and spreading on all other configured
physical channels by spreading blocks 1914, the I and Q branches of
all the configured physical channels, (e.g., DPCCH, DPDCH,
HS-DPCCH, E-DPCCH, and E-DPDCH), are summed by the combiners 1916
into two complex-valued streams, which are then scrambled by the
scramblers 1918 with one or two complex-valued scrambling codes.
The WTRU then transmits data on both antennas after filtering. The
WTRU may signal the pre-coding weights on the UL, which will be
explained in detail below.
[0132] FIG. 19 shows that the precoding is performed after the
spreading and combining of the E-DPDCH(s) and E-DPCCH(s). However,
the pre-coding operation may be performed at any stage, either at
the symbol or chip level, and may be applied to one or more data or
control channels before or after spreading or scrambling operations
depending on the pre-coder's location in the transmitter.
[0133] FIG. 20 shows an example transmitter 2000 in accordance with
another embodiment. In this embodiment, the pre-coding is applied
to the E-DPDCHs after spreading operation. The transmitter
comprises physical layer processing blocks 2002 for E-DPDCH,
spreading blocks 2004, 2010, 2014, combining blocks 2012, 2016, a
precoder 2006, a weights selection block 2008, scramblers 2018,
filters 2020, and antennas 2022. Primary and secondary E-DCH
transport blocks, if dual-stream is configured, (or a primary E-DCH
transport block if one stream is configured), are processed by the
physical layer processing blocks 2002 for E-DCH. The physical layer
processing may include adding CRC parity bits to the transport
block, code block segmentation, channel coding, physical layer
HARQ, rate matching, physical channel segmentation, interleaving
and mapping to E-DPDCH1 and E-DPDCH2 if dual-stream is configured,
respectively, (or to E-DPDCH1 if a single stream is
configured).
[0134] After the physical layer processing, the data streams on the
E-DPDCH1 and E-DPDCH2 are spread by the spreading blocks 2004.
After the spreading operation, the chip streams are processed by
the precoder 2006. The pre-coder 2006 applies pre-coding weights
determined by the weights selection block 2008 to distribute the
signals to the antennas 2022. Depending on the number of transport
blocks scheduled for transmission, the weights selection block 2008
may provide one or more sets of pre-coder weights.
[0135] Spreading operation on the E-DPCCH1 and the E-DPCCH2, and
all other physical channels is performed by the spreading blocks
2010, 2014, respectively. After the spreading operation on the
E-DPCCH(s) and all other configured physical channels, the chips on
the I and Q branches of all the configured physical channels,
(e.g., DPCCH, DPDCH, HS-DPCCH, E-DPCCH, and E-DPDCH), are summed by
the combiners 2012, 2016 into two complex-valued streams, which are
then scrambled by the scramblers 2018 with one or two
complex-valued scrambling codes. The WTRU then transmits data on
both antennas after filtering.
[0136] In accordance with this embodiment, since control channels
are not pre-coded, the conventional receiver may be used to receive
the control channels without a need to inverse the spatial
pre-coding operation for the control information. Further, since
the E-DPCCH is not pre-coded, it may be decoded using a different
receiver than the one for the E-DPDCH, which may expedite decoding
of the transport block size, happy bit, and retransmission sequence
number (RSN) information, thus reducing the decoding latency.
[0137] In addition, the E-DPCCH reliability may be linked to the
DPCCH, which is power-controlled and experiences the same channel
conditions. In that way the reliability of the control channel
becomes independent of the pre-coding. Further, compared with data
channels, much stronger protection may be given to the control
channels so that they may be demodulated and decoded correctly with
much higher probability. The control channels may not be pre-coded
since spatial multiplexing of two control channels would generate
inter-stream interferences and consequently may cause performance
degradation. Instead, to provide additional transmit diversity gain
and improve reception reliability to the control channels, an open
loop transmit diversity scheme such as space time block coding
(STBC) may be implemented.
[0138] In addition, since E-DPCCH1 and E-DPCCH2 are sent over the
two different antennas without pre-coding, both E-DPCCHs may be
used as additional pilot information (in decision directed mode)
for improved channel estimation.
[0139] FIG. 21 shows an example transmitter 2100 in accordance with
another embodiment. In this embodiment, the pre-coding operation is
applied to not only the E-DPCCH and the E-DPDCH but also to the
HS-DPCCH after spreading operations. The transmitter 2100 comprises
physical layer processing blocks 2002 for E-DPDCH, spreading blocks
2104, 2106, 2108, 2118, combining blocks 2110, 2112, 2120, a
precoder 2114, a weights selection block 2116, scramblers 2122,
filters 2124, and antennas 2126.
[0140] Primary and secondary E-DCH transport blocks, if dual-stream
is configured, (or a primary E-DCH transport block if one stream is
configured), are processed by the physical layer processing blocks
2102 for E-DCH. The physical layer processing may include adding
CRC parity bits to the transport block, code block segmentation,
channel coding, physical layer HARQ, rate matching, physical
channel segmentation, interleaving and mapping to E-DPDCH1 and
E-DPDCH2 if dual-stream is configured, respectively, (or to
E-DPDCH1 if a single stream is configured). Either E-DPDCH1 or
E-DPDCH2 may comprise one or more E-DPDCHs depending on the E-TFCI
selected for the transport block, which may or may not be the same,
(i.e., the primary transport block may be mapped to one or more
E-DPDCHs in E-DPDCH1 and the secondary transport block may be
mapped to one or more E-DPDCHs in E-DPDCH2).
[0141] After the physical layer processing, the spreading blocks
2104 perform spreading operation on the E-DPDCH1 and E-DPDCH2.
Spreading operation on the E-DPCCH1 and E-DPCCH2, after physical
layer processing, is performed by the spreading blocks 2106.
Spreading operation on the HS-DPCCH, after physical layer
processing, is also performed by the spreading block 2108. After
the spreading operation, the real-valued chips on the I and Q
branches of the E-DPDCH(s), the E-DPCCH(s), and the HS-DPCCH are
summed by the combiners 2110, 2112 into two complex-valued streams.
The two complex-valued streams are then processed by the pre-coder
2114. The pre-coder 2114 applies pre-coding weights determined by
the weights selection block 2116 to distribute the signals to the
antennas 2126.
[0142] DPCCH(s) and DPDCH(s) are spread by the spreading blocks
2118. The real-valued chips on the I and Q branches of all the
configured physical channels, (e.g., DPCCH, DPDCH, HS-DPCCH,
E-DPCCH, and E-DPDCH), are summed by the combiners 2120 into two
complex-valued streams, which are then scrambled by the scramblers
2122 with one or two complex-valued scrambling codes. The WTRU then
transmits data on both antennas after filtering. The WTRU may
signal the pre-coding weights on the UL, which will be explained in
detail below.
[0143] FIG. 21 shows that the precoding is performed after the
spreading and combining of the E-DPDCH, E-DPCCH, and HS-DPCCH.
However, the pre-coding operation may be performed at any stage, at
either symbol or chip level, and may be applied to one or more data
or control channels before or after spreading or scrambling
operations depending on the pre-coder's location in the
transmitter.
[0144] This embodiment allows the control channels (including the
HS-DPCCH) to take advantage of the additional coverage that
pre-coding may provide including the single-stream case.
[0145] The precoding weights applied to the E-DPCCH and the
HS-DPCCH in case of a single E-DPDCH stream being transmitted may
be different from those when two E-DPDCH streams are being
transmitted, since weight generation for diversity may be different
from the one for spatial-multiplexing. When there is one E-DPDCH
stream, it may share the same precoding weights as E-DPCCH and
HS-DPCCH.
[0146] FIG. 22 shows an example transmitter 2200 in accordance with
another embodiment. In this embodiment, the pre-coding is applied
to the E-DPDCH(s) before spreading operations, (i.e., at the symbol
level). The processing power for pre-coding operation may be saved
as it is less computationally intensive to apply the weights at the
symbol level rather than at the chip level.
[0147] The transmitter 2200 comprises physical layer processing
blocks 2202 for E-DPDCH, a precoder 2204, a weights selection block
2206, spreading blocks 2208, 2210, 2214, combining blocks 2212,
2216, scramblers 2218, filters 2220, and antennas 2222. Primary and
secondary E-DCH transport blocks, if dual-stream is configured, (or
a primary E-DCH transport block if one stream is configured), are
processed by the physical layer processing blocks 2202 for E-DCH.
The physical layer processing may include adding CRC parity bits to
the transport block, code block segmentation, channel coding,
physical layer HARQ, rate matching, physical channel segmentation,
interleaving and mapping to E-DPDCH1 and E-DPDCH2 if dual-stream is
configured, respectively, (or to E-DPDCH1 if a single stream is
configured).
[0148] After the physical layer processing, the data streams, on
the E-DPDCH1 and E-DPDCH2 are processed by the precoder 2204 at
symbol level, (i.e., before spreading). The pre-coder 2204 applies
pre-coding weights determined by the weights selection block 2206
to distribute the signals to the antennas 2222. Depending on the
number of transport blocks scheduled for transmission, the weights
selection block 2206 may provide one or more sets of pre-coder
weights.
[0149] After the precoding, the data streams are spread by the
spreading blocks 2208. Spreading operation on the E-DPCCH1 and the
E-DPCCH2, and all other physical channels is performed by the
spreading blocks 2210, 2214, respectively. After the spreading
operation on the E-DPDCH(s), E-DPCCH(s) and all other configured
physical channels, the chips on the I and Q branches of all the
configured physical channels, (e.g., DPCCH, DPDCH, HS-DPCCH,
E-DPCCH, and E-DPDCH), are summed by the combiners 2212, 2216 into
two complex-valued streams, which are then scrambled by the
scramblers 2218 with one or two complex-valued scrambling codes.
The WTRU then transmits data on both antennas 2222 after
filtering.
[0150] FIG. 23 shows an example transmitter 2300 in accordance with
another embodiment. In accordance with this embodiment, the
pre-coding operation is applied to all channels including both
control and data channels after scrambling operations. The
transmitter 2300 comprises physical layer processing blocks 2302
for E-DPDCH, spreading blocks 2304, 2306, 2308, combining blocks
2310, 2312, scramblers 2314, a precoder 2316, a weights selection
block 2318, filters 2320, and antennas 2322. Primary and secondary
E-DCH transport blocks, if dual-stream is configured, (or a primary
E-DCH transport block if one stream is configured), are processed
by the physical layer processing blocks 2302 for E-DCH. The
physical layer processing may include adding CRC parity bits to the
transport block, code block segmentation, channel coding, physical
layer HARQ, rate matching, physical channel segmentation,
interleaving and mapping to E-DPDCH1 and E-DPDCH2 if dual-stream is
configured, respectively, (or to E-DPDCH1 if a single stream is
configured).
[0151] After the physical layer processing, the data streams on the
E-DPDCH1 and E-DPDCH2 are spread by the spreading blocks 2304.
Spreading operation on the E-DPCCH1 and the E-DPCCH2, and all other
physical channels is performed by the spreading blocks 2306, 2308,
respectively. After the spreading operation on the E-DPDCH(s),
E-DPCCH(s) and all other configured physical channels, the chips on
the I and Q branches of all the configured physical channels,
(e.g., DPCCH, DPDCH, HS-DPCCH, E-DPCCH, and E-DPDCH), are summed by
the combiners 2310, 2312 into two complex-valued streams, which are
then scrambled by the scramblers 2314 with one or two
complex-valued scrambling codes.
[0152] After the scrambling operation, the pre-coding operation is
performed by the precoder 2316 on the combined data stream of all
channels. The pre-coder 2316 applies pre-coding weights determined
by the weights selection block 2318 to distribute the signals to
the antennas 2322. Depending on the number of transport blocks
scheduled for transmission, the weights selection block 2318 may
provide one or more sets of pre-coder weights. The transmitter 2300
then transmits data on both antennas after filtering.
[0153] Two different scrambling codes may be used for the two
antennas. Alternatively, a single scrambling code may be used for
the antennas. If two different scrambling codes are configured by
the network, the same orthogonal variable spreading factor (OVSF)
codes, (i.e., the channelization codes), used on the DPCCH, DPDCH
and E-DPCCH for the primary stream may be reused for those for the
secondary stream if the dual-stream is configured with different
modulation and coding scheme (MCS). Furthermore, if a dual-stream
is configured, the OVSF codes used for the primary stream may be
reused for the secondary stream under certain conditions including,
but not limited to: if both streams use the same transport format,
if both stream use the same MCS, and/or if both stream use the same
E-TFCI. Otherwise, the WTRU may use a different set of
channelization code(s) for the second stream. The channelization
code(s) for the second set of E-DPDCHs may be taken from a
different OVSF branch altogether, selected in such a way to
minimize inter-stream interference and/or cubic metric impacts.
[0154] With two different scrambling codes, from the network or the
Node-B perspective, the two streams may be interpreted as if they
were coming from two different WTRUs. From an implementation
perspective, this may allow minimal changes in the Node-Bs receiver
architecture (as small as a software upgrade) and at the system
level may not impact the resources allocation and cell planning so
much as the uplink is not typically limited by the number of
scrambling codes but rather from the interference. With the special
case of a diagonal precoder,
( e . g . , [ 1 0 0 1 ] ) , ##EQU00002##
this transmitter structure from the physical layer perspective
becomes almost equivalent to having two separate WTRUs. This may be
advantageous from both the Node-B and the WTRU implementation
perspective as it would simplify implementation significantly.
[0155] FIG. 24 shows an example transmitter 2400 in accordance with
another embodiment. In accordance with this embodiment, the
pre-coding operation is applied to all channels including both
control and data channels before scrambling operations. Optionally,
pre-coding operation may be done before scrambling operations,
which is mathematically equal when using the same scrambling. The
transmitter 2400 comprises physical layer processing blocks 2402
for E-DPDCH, spreading blocks 2404, 2406, 2408, combining blocks
2410, 2412, a precoder 2414, a weights selection block 2416,
scramblers 2418, filters 2420, and antennas 2422. Primary and
secondary E-DCH transport blocks, if dual-stream is configured, (or
a primary E-DCH transport block if one stream is configured), are
processed by the physical layer processing blocks 2402 for E-DCH.
The physical layer processing may include adding CRC parity bits to
the transport block, code block segmentation, channel coding,
physical layer HARQ, rate matching, physical channel segmentation,
interleaving and mapping to E-DPDCH1 and E-DPDCH2 if dual-stream is
configured, respectively, (or to E-DPDCH1 if a single stream is
configured).
[0156] After the physical layer processing, the data streams on the
E-DPDCH1 and E-DPDCH2 are spread by the spreading blocks 2404.
Spreading operation on the E-DPCCH1 and/or the E-DPCCH2, and all
other physical channels is performed by the spreading blocks 2406,
2408, respectively. After the spreading operation on the
E-DPDCH(s), E-DPCCH(s) and all other configured physical channels,
the chips on the I and Q branches of all the configured physical
channels, (e.g., DPCCH, DPDCH, HS-DPCCH, E-DPCCH, and E-DPDCH), are
summed by the combiners 2410, 2412 into two complex-valued
streams.
[0157] A pre-coding operation is then performed by the precoder
2414 on the combined two complex data streams of all channels. The
pre-coder 2414 applies pre-coding weights determined by the weights
selection block 2416 to distribute the signals to the antennas
2422. Depending on the number of transport blocks scheduled for
transmission, the weights selection block 2416 may provide one or
more sets of pre-coder weights. After the precoding, the data
streams are scrambled by the scramblers 2418 with one or two
complex-valued scrambling codes. The transmitter 2400 then
transmits data on both antennas 2422 after filtering.
[0158] When two different scrambling codes are used for both
antennas, separation of each stream may be achieved via scrambling
code in the transmitter of FIG. 23, whereas per-antenna separation
may be achieved via scrambling code in the transmitter of FIG. 24.
Having a means to separate the signals at the antenna may be
advantageous for channel estimation when the DPCCH is pre-coded, as
is the case in this embodiment.
[0159] In accordance with this embodiment, the Node-B receiver may
separate signals based on antenna, and even if the pilot signals
are pre-coded, the channel matrix may be estimated correctly so
that the Node-B may determine which set of precoding weights to
signal to the WTRU. In accordance with this embodiment, the
effective space-time channel for each stream may be estimated with
a single DPCCH for detection, and the channel matrix may be
estimated by separating via scrambling codes. This structure also
has an advantage that for single stream transmission, minimum or no
change on the receiver side is needed. This may have significant
advantage for reducing implementation cost for certain technologies
which are widely deployed such as UTRA.
[0160] FIG. 25 shows an example transmitter 2500 in accordance with
another embodiment. The transmitter 2500 is similar to the
transmitter 2100 of FIG. 21. A difference is that pre-coding is
also applied to DPDCH, if configured, after spreading operations.
This allows the DPDCHs to benefit from pre-coding and the closed
loop transmit gain that may result. In other words, transmitter
2500 applies pre-coding to all configured channels except DPCCH1
and DPCCH2.
[0161] Transmitted signal structure and spreading operations are
explained hereafter. For any transmitter embodiments described
above, the transmitted signal, (i.e., the possible dedicated
physical channels which may be configured simultaneously for a
WTRU), may comprise one or more of, in any combination: DPCCH1,
DPCCH2, DPDCH1, DPDCH2, HS-DPCCH, E-DPDCH1, E-DPDCH2, E-DPCCH1,
and/or E-DPCCH2.
[0162] DPCCH1 and DPCCH2 are transmitted using OVSF code Cc1 and
Cc2, respectively, to support channel estimation at the Node-B by
using pilot signal and carry the control information. If pilot
signal (at the symbol level) in DPCCH1 and DPCCH2 are orthogonal,
the OVSF code Cc1 and Cc2 may be the same. If the same pilot signal
is used in both DPCCH1 and DPCCH2, the OVSF code Cc1 and Cc2 should
be orthogonal. Both DPCCH1 and DPCCH2 may be transmitted in pair
unless during the period where the UL transmission is not allowed,
for example, when the WTRU is in DTX or compressed mode.
[0163] The control information carried on the DPCCH1 may include
transport format combination index (TFCI), feedback information
(FBI) and transmit power control (TPC). The DPCCH2 may carry a
pilot signal. Alternatively, the DPCCH2 may carry another set of
control information besides the pilot signal, which may include
part or all of the control information carried on the DPCCH1,
and/or other new control information, such as pre-coding weight,
etc.
[0164] Depending on the number of DPDCH data streams being
transmitted, one or two set of DPDCH(s) may be transmitted on two
antennas. Two sets of DPDCH, (i.e. DPDCH1 and DPDCH2), may be
respectively transmitted by using OVSF code set Cd1 and Cd2. Either
DPDCH1 or DPDCH2 may comprise zero, one or more DPDCHs which may or
may not be the same. The actual number of configured DPDCHs in
DPDCH1 and DPDCH2, (denoted N.sub.max-dpdch1 and N.sub.max-dpdch2),
may be respectively equal to the largest number of DPDCHs from all
the transport format combinations (TFCs) in the transport format
combination set (TFCS). Alternatively, neither DPDCH1 nor DPDCH2
may be transmitted when no DPDCH data stream is configured.
Alternatively, DPDCH1 may be transmitted using OVSF code set Cd1
when a single DCH data stream is configured. To maintain the
backward compatibility to 3GPP Release 9, when an E-DCH is
configured, either N.sub.max-dpdch1 or N.sub.max-dpdch2 may be 0 or
1, or N.sub.max-dpdch1 may be 0 or 1 while N.sub.max-dpdch2 is
0.
[0165] The HS-DPCCH may be transmitted using OVSF code Chs to carry
HARQ ACK/NACK, channel quality indicator (CQI) and precoding
indicator (PCI) if the WTRU is in a downlink (DL) MIMO mode.
[0166] The E-DPCCH1 and E-DPCCH2 may be respectively transmitted
using OVSF code Cec1 and Cec2 to provide the control information to
the associated the E-DCH. For a single stream case, the E-DPCCH1
may be transmitted. Alternatively, a single E-DPCCH may be used to
carry the information for both streams, in which case Cec1 may be
used.
[0167] A new E-DPCCH frame/slot format and/or coding scheme may be
used to carry all the necessary information. In accordance with one
embodiment, a new slot format allowing more information symbols to
be carried in a single TTI is used. For example, the new slot
format may use a smaller spreading factor, (e.g., 128 instead of
256), to allow twice the number of information symbols to be
carried in one TTI of the E-DPCCH. In that case, the conventional
coding scheme for the E-DPCCH may be re-used for each stream
independently.
[0168] In accordance with another embodiment, time-division
multiplexing may be used to transmit the two E-DPCCHs. For
instance, E-DPCCH1 and E-DPCCH2 may be carried in the first and
second half of the TTI, respectively. Another field may be included
in the E-DPCCH1 and/or E-DPCCH2 to indicate the number of streams
transmitted in the current TTI. In case a single stream is being
transmitted, the E-DPCCH1 may be repeated in the second half of the
subframe. In such cases, when E-DPCCH power boosting is configured,
the WTRU may calculate the required power boosting for each E-DPCCH
and apply the largest one of the two for both E-DPCCHs that are
time-multiplexed in the same E-DPCCH subframe.
[0169] In accordance with another embodiment, a new coding scheme
may be used whereby the information for both E-DCH streams is
jointly encoded in a single E-DPCCH. A new field may be introduced
in the new E-DPCCH to indicate the number of streams carried in the
TTI. This new E-DPCCH may carry, for example, a number of streams
indicator bit, a single "Happy bit" value, one E-TFCI per stream
and one retransmission sequence number (RSN) per stream for up to
20 bits of information. This new E-DPCCH may be carried using the
conventional slot format with spreading factor of 256 or
alternatively using a lower spreading factor. This new E-DPCCH may
be encoded using an existing code or a new code, (e.g., a new (30,
20) code for the case where SF 256 is used, or a new (60, 20) code
in case SF of 128 is used). The WTRU may apply a larger power
offset to the E-DPCCH when two streams are being transmitted to
ensure reliable reception. When a single stream is transmitted, the
fields carrying the E-TFCI and the RSN for the second stream may be
DTXed.
[0170] Depending on the number of streams to be transmitted, one or
two set, (i.e., multiple codes), of E-DPDCH may be transmitted. For
dual-stream case where the WTRU performs the E-TFC selection, which
results in two transport blocks to be transmitted and the WTRU
applies the OVSF configuration corresponding to dual stream
transmission and transmits the dual streams, the E-DPDCH1 and the
E-DPDCH2 may be respectively transmitted using OVSF code set Ced1
and Ced2. Either E-DPDCH1 or E-DPDCH2 may comprise one or more
E-DPDCHs depending on the E-TFCI selected for either primary or
secondary E-DCH transport block, which may or may not be of the
same size. In the dual stream case, each E-DCH transport block may
have a different size or E-TFCI, so the channelization code set
Ced1 and Ced2 may or may not be different. Alternatively, for a
single stream case where one transport block of E-DCH is scheduled,
the E-DPDCH1 may be transmitted by using OVSF code set Ced1 which
may be, for example, the conventional OVSF code set used for single
carrier HSUPA without MIMO configured.
[0171] If the spreading factor determination results in two
different channelization codes Ced1 and Ced2 for the E-DPDCH1 and
E-DPDCH2, respectively, to ensure the mathematical or functional
equivalence between the case of precoding in symbol level before
spreading and the case of precoding in chip level after spreading,
Ced1, Ced2 may be chosen such that one of them may be the
repetition of the other.
[0172] When the WTRU is configured in a closed-loop transmit
diversity (CLTD) mode or a single stream MIMO mode, neither
E-DPDCH2 nor E-DPCCH2 may be configured or transmitted. More
specifically, when a single E-DCH stream is being transmitted, the
second set of E-DCH data and control channels may not be
transmitted by the WTRU.
[0173] The DPCCH2 may be mapped to I or Q branch. In order to
select the best channelization code for the DPCCH2, first, the
available channelization code space is searched for the DPCCH2 by
not selecting the code used by other channels on either I or Q
branches to reduce the phase error during channel estimation.
Depending on whether a DCH is configured or not, the available
channelization code space obtained in the first step may be
different. Among the available code space, the best channelization
code is selected to obtain a smaller cubic metric (CM) value than
other codes given a transmitter structure and configuration. For
example, when using the transmitter 2400 with a CLTD mode
configuration, if the DPCCH2 is configured on an I branch, the
channelization code of the DPCCH2 may be selected as C.sub.ch, 256,
32, and if the DPCCH2 is configured on a Q branch, the
channelization code of the DPCCH2 may be selected as C.sub.ch, 256,
2.
[0174] The OVSF codes Cc1, Cc2, Cd1, Cd2, Chs, Cec1, Cec2, Ced1,
and Ced2 may be fixed in the standards or configured by the
network.
[0175] FIG. 26 shows the spreading operation, which includes
spreading with a given channelization code, weighting, and IQ phase
mapping. The spreading operation is applied to every physical
channel. The spreading operation may be represented by:
SF.sub.--CH=CH*C.sub.CH*.beta..sub.CH*iq.sub.CH Equation (5)
where, CH is the real-valued bits of the physical channel to be
spread and weighted, C.sub.CH is the OVSF channelization code fixed
in the standards or configured by the network, .beta..sub.CH is a
gain factor that may be signaled or calculated based on the
signaled parameters and the transport block size or number of
information bits, iq.sub.CH is a complex value for the I or Q
branch mapping, where iq.sub.CH=1 or iq.sub.CH=j.
[0176] After spreading operation, the streams of real-valued chips
on I and Q branches are summed into two complex-valued streams
which are then scrambled by one or two complex-valued scrambling
codes configured by the network. The operation is carried out as
follows: the WTRU receives a configuration message carrying
scrambling code information. The WTRU applies the scrambling code
to the complex-valued streams. Scrambling may be carried out after
the spreading operation for each channel separately, after the
spread channels are all summed together, or after summing of all
non-precoded and pre-coded channels as shown in different
transmitter embodiments described above. Optionally, the WTRU may
apply the pre-coding weights to two complex scrambled streams if
transmitter 2300 is used. The WTRU then transmits data on both
antennas after filtering with transmit pulse, (e.g., a root
raised-cosine filter).
[0177] Pre-coding operations are explained hereafter. FIG. 27 shows
an example pre-coder for the dual stream case. The precoding
operation may be represented as follows:
[ B p B s ] = W [ A p A s ] = [ w 1 w 3 w 2 w 4 ] [ A p A s ] = [ w
1 A p + w 3 A s w 2 A p + w 4 A s ] , where W = [ w 1 w 3 w 2 w 4 ]
Equation ( 6 ) ##EQU00003##
is the pre-coding matrix. A.sub.p and A.sub.s may be complex or
real values. After applying the pre-coding operation, A.sub.p and
A.sub.s are distributed on the first and second transmit antenna,
which are represented by B.sub.p=w.sub.1A.sub.p+w.sub.3A.sub.s and
B.sub.s=w.sub.2A.sub.p+w.sub.4A.sub.s, respectively.
[0178] When A.sub.s=0, (i.e., a single stream case),
B.sub.p=w.sub.1A.sub.p and B.sub.s=w.sub.2A.sub.p are respectively
sent on the first and second antenna.
[0179] FIG. 28 shows another example pre-coder for the dual stream
case. In HSUPA, real-valued I/Q branches are separated before I/Q
multiplexing. The pre-coding operation is applied to the I and Q
branches of each of the primary and secondary streams A.sub.p and
A.sub.q, respectively, then I/Q multiplexing is performed on the
pre-coded I/Q branch data. In accordance with this embodiment, the
I/Q branches are processed in parallel, reducing the implementation
complexity. Mathematically, the outputs of the two pre-coders are
the same given the same input, which may be represented as
follows:
[ B p B s ] = W [ A p A s ] = [ w 1 w 3 w 2 w 4 ] [ A p , I + j A p
, Q A s , i + j A s , Q ] = [ w 1 w 3 w 2 w 4 ] ( [ A p , I A s , i
] + j [ A p , Q A s , Q ] ) = [ w 1 w 3 w 2 w 4 ] [ A p , I A s , I
] + j [ w 1 w 3 w 2 w 4 ] [ A p , Q A s , Q ] Equation ( 7 )
##EQU00004##
where A.sub.p=A.sub.p,I+jA.sub.p,Q, A.sub.s=A.sub.s,I+jA.sub.s,Q,
and A.sub.p,I and A.sub.s,I are the real part (I branch) of the
complex-valued A.sub.p and A.sub.s, A.sub.p,Q, and A.sub.s,Q, are
the image part (Q branch) of the complex-valued A.sub.p and
A.sub.s. The above two pre-coder embodiments may be used for one or
more physical channels, and may be used in combination with any
transmitter structures described herein.
[0180] In order to save on computing complexity, the pre-coding may
be performed at the symbol level as opposed to the chip level. For
these to be equivalent, the channelization codes (or spreading
codes), gain factor and I/Q mapping need to be the same for both
channels to pre-code, or the precoding weight matrix W is
diagonal.
[0181] FIG. 29 shows another example pre-coder for the dual stream
case. If the two streams use different spreading factors, for the
pre-coding-before-spreading be equivalent to the
spreading-before-pre-coding the spreading code of the highest data
rate channel needs to be constructed from a repetition of the
spreading code for the lowest data rate channel. For example,
assuming two channels with spreading factors 2 and 4 are being
transmitted. If the channelization code for the channel with a
spreading factor 2 is C.sub.ch2=[1 -1], the channelization code for
the channel with a spreading factor 4 may be C.sub.ch4=[C.sub.ch2
C.sub.ch2]=[1 -1 1 -1].
[0182] In FIG. 29, the precoding is applied before spreading and
two data streams C.sub.s and C.sub.p (assuming C.sub.ed1 and
C.sub.ed2 are OVSF codes for data streams C.sub.s and C.sub.p,
respectively) use OVSFs with different spreading factors SF.sub.ed1
and SF.sub.ed2 with SF.sub.ed2=N.times.SF.sub.ed1. The data stream
with the lowest (or lower) symbol rate (C.sub.s) is weighted and
repeated N times before mixed with the other stream (C.sub.p) that
is weighted. At the output of the precoder, both streams D.sub.s
and D.sub.p are spread with the channelization code of the smallest
spreading factor of SF.sub.ed1 and SF.sub.ed2 (C.sub.ed1 in this
example).
[0183] The above embodiment may be applied for example to the E-DCH
transmission with four E-DPDCHs. FIG. 30 shows an example
transmitter for the two stream case. For applying pre-coding before
spreading, the channels are grouped first with respect to their
spreading factor, (i.e., channels of the same spreading factors are
grouped together), and the data streams are pre-coded and then
spread.
[0184] E-DPDCH.sub.k.sup.(l) is defined as the k.sup.th E-DPDCH for
the l.sup.th stream. Four E-DPDCHs are used for each of the two
data streams. For each stream, the first and second E-DPDCHs are
spread using the same channelization code of the same spreading
factor, (e.g., 2), and the first E-DPDCH is mapped on the I branch
and the second E-DPDCH is mapped on the Q branch, and the third and
fourth E-DPDCHs are spread using the same channelization code of
the same spreading factor, (e.g., 4), and the third E-DPDCH is
mapped on the I branch and the fourth E-DPDCH is mapped on the Q
branch. In FIG. 30, the first and second E-DPDCHs of the first
stream are combined by a combiner 3002 into a complex signal, and
the first and second E-DPDCHs of the second stream are combined by
a combiner 3004 into a complex signal and then pre-coded by a
pre-coder 3010, and the third and fourth E-DPDCHs of the first
stream are combined by a combiner 3006 into a complex signal, and
the third and fourth E-DPDCHs of the second stream are combined by
a combiner 3008 into a complex signal and then pre-coded by a
pre-coder 3012. After the pre-coding, the first and second E-DPDCHs
of the two streams are spread by channelization blocks 3014, 3016
with a channelization code of the same spreading factor, (in this
example, a channelization code of spreading factor 2
(C.sub.ch,2,1)), and the third and fourth E-DPDCHs of the two
streams are spread by channelization blocks 3018, 3020 with a
channelization of the same spreading factor, (in this example, a
channelization code of spreading factor 4 (C.sub.ch,4,1)). After
spreading, the antenna components are combined by the combiners
3022, 3024 for transmission.
[0185] Other combination of pairs of E-DCHs may also be
implemented. Up to two E-DPDCHs from the same stream mapped on
different I/Q branches may be combined together for pre-coding. The
inputs to the pre-coder may comprise two complex signals from each
stream. If the spreading factor for all inputs to the pre-coder is
the same, the channelization codes for input channels to the same
pre-coder may be the same. If all inputs to the pre-coder do not
have the same data rate or spreading factor, the lower data rate
input(s) may be repeated for matching the highest data rate
input.
[0186] A combination of the approaches illustrated in FIG. 28 and
FIG. 29 may be used to optimize the computational complexity of
applying the precoding operation.
[0187] It is further noted that the embodiments illustrated in
FIGS. 28-30 may also be used to other pair of channels besides the
E-DPDCH when the spreading code properties permits.
[0188] Embodiments for generating pre-coding weights are described.
The pre-coding weights matrix W may be chosen from a set of
pre-coder matrices, (i.e., codebook), or be determined without a
codebook.
[0189] If codebook-based pre-coding is used, unitary matrices may
be used as the pre-defined pre-coder matrix. One example codebook
is as follows:
W .di-elect cons. { 1 2 [ 1 1 1 - 1 ] , 1 2 [ 1 1 j - j ] , [ 1 2 1
2 1 + j 2 - 1 - j 2 ] , [ 1 2 1 2 1 - j 2 - 1 + j 2 ] , [ 1 0 0 1 ]
} . ##EQU00005##
[0190] DL MIMO pre-coding matrix may be reused for the UL MIMO,
whose weights w.sub.1, w.sub.2, w.sub.3 and w.sub.4 of the
2.times.2 pre-coding matrix are defined as follows:
w 3 = w 1 = 1 / 2 , Equation ( 8 ) w 4 = - w 2 , Equation ( 9 ) w 2
.di-elect cons. { 1 + j 2 , 1 - j 2 , - 1 + j 2 , - 1 - j 2 } .
Equation ( 10 ) ##EQU00006##
[0191] If a single transport block is scheduled in one TTI, the
pre-coding vector (w.sub.1, w.sub.2) may be used for transmission.
If two transport blocks are scheduled in one TTI, two orthogonal
pre-coding vectors may be used to transmit the two transport
blocks. The pre-coding vector (w.sub.1, w.sub.2) may be called the
primary pre-coding vector which is used for transmitting the
primary transport block and the pre-coding vector (w.sub.3,
w.sub.4) may be called the secondary pre-coding vector which is
used for transmitting the secondary transport block,
respectively.
[0192] If non-codebook-based pre-coding is used, the pre-coding may
be based on transmit beamforming (TxBF), for example,
eigen-beamforming based on singular value decomposition (SVD). For
pre-coding using eigen-beamforming, the channel matrix H is
decomposed using an SVD, (i.e., a pre-coding matrix W is a unitary
matrix chosen such that H=U.SIGMA.W.sup.H. The eigen-channel's
signal-to-noise ratio (SNR) may be matched by selecting a suitable
modulation and coding scheme (MCS) for each stream.
[0193] Generally, non-codebook-based pre-coding schemes give the
better performance and more freedom to the size of the codebook
than codebook-based pre-coding at the cost of feedback signaling
overhead in the DL and potential control signaling overhead in the
UL.
[0194] The special case of the identity matrix
( [ 1 0 0 1 ] ) ##EQU00007##
as a pre-coding codebook is equivalent for certain transmitter
structures in single stream operations to a switch antennas
transmitter (thereby using switch antenna transmit diversity
(SATD)). For example, this is the case for transmitter 2100 and
2500 and also 2300 and 2400 when the same scrambling code is
used.
[0195] Embodiments for selecting and signaling the pre-coding
weights are explained hereafter.
[0196] When channel-dependent MIMO schemes are used for HSUPA,
channel-dependent information may be sent from a Node-B to a WTRU
for pre-coding operation. This information allows the WTRU to
adjust the pre-coding weights as a function of the channel
propagation conditions. For example, this channel-dependent
feedback information may comprise uplink pre-coding control
indication (UPCI), channel state information (CSI), or CSI-related
information (such as serving grants carried on an E-DCH absolute
grant channel (E-AGCH), an E-DCH relative grant channel (E-RGCH) or
TPC commands carried on DL DPCCH/F-DPCCH, etc.).
[0197] A Node-B may determine a set of pre-coding weights, and
indicate it to the WTRU. For example, the set of pre-coding weights
may be indicated to the WTRU via a control signal carrying uplink
pre-coding control information (UPCI).
[0198] The UPCI may be transmitted by the Node-B using an E-DCH
HARQ indicator channel (E-HICH) and an E-RGCH. The E-HICH and
E-RGCH are both currently using a similar structure. Forty (40)
signatures are defined with forty sequences which comprise a
pre-defined signature hopping pattern over 3 radio slots. For
normal operations, the network assigns one sequence per E-HICH or
E-RGCH which are modulated by values +1, -1 or 0 (DTX) by the
Node-B. In one implementation of UPCI signaling (which applies to
both E-HICH and E-RGCH), the WTRU may receive the UPCI through a
variation of this E-HICH/E-RGCH structure.
[0199] FIG. 31A shows an example UPCI signaling using an E-HICH. In
this embodiment, a WTRU may be configured to listen to a specific
E-HICH channelization code from, for example, an E-DCH serving
cell. As shown in FIG. 31A, the first radio slot 3102 of the E-HICH
subframe carries the conventional E-HICH signal while the
subsequent two radio slots 3104 of the E-HICH subframe carry the
signaling for the UPCI. Alternatively, the first two radio slots of
the E-HICH subframe may carry the E-HICH signal while the last
radio slot of the E-HICH subframe carry the signaling for the UPCI.
Any other variations are also possible. This embodiment allows the
network to save on channelization code space, at the expense of
additional transmission power to maintain similar reliability level
for the E-HICH. The same approach may also be used for the
E-RGCH.
[0200] The WTRU may be configured to listen to the UPCI
periodically, with a certain configured or pre-defined period. In
case where the WTRU is not configured to listen to the UPCI, the
conventional three radio slots of the E-HICH subframe may carry the
conventional E-HICH information (if present). This allows reducing
the amount of downlink signaling for support of UL MIMO operations.
The same approach may also be used for the E-RGCH. FIG. 31B
illustrates the case where one out of seven E-HICH subframes
carries the UPCI field. Even if the Node-B has no ACK/NACK to
transmit during those periods, the UPCI field may be
transmitted.
[0201] In accordance with another embodiment, a new set of
orthogonal signature sequences may be used to signal the UPCI via
the E-HICH, the E-GRCH, or a different channel. The new signature
sequences may or may not be used in combination with the signature
hopping pattern of the E-HICH or the E-RGCH. For example, the new
sequences may be modulated by +1, -1 by the UPCI information
bits.
[0202] To carry more than one information bit, multiple sequences
may be used. Alternatively, the information bits may modulate a
given radio slot in the three slots sequence. For example, the
first half of the sub-frame may be modulated by the first
information bit of the UPCI, (e.g., a most significant bit (MSB)),
while the second half may be modulated by the second information
bit of the UPCI, (e.g., a least significant bit (LSB)).
Alternatively, in case two UPCI information bits need to be
transmitted, two of the three radio slots may be used to transmit
the information and the remaining radio slot of the subframe may be
DTXed. The radio slots for the UPCI information may not be
consecutive, (e.g., the first and third radio slots may be used for
the UPCI information and the second radio slot may be DTXed).
[0203] The signature sequences may be received by the WTRU at the
same time as the conventional sequences over a channelization code
that is orthogonal to the one used by the E-HICH/E-RGCH. The WTRU
may be configured by the network to monitor one or more such new
sequences on one or more E-HICH/E-RGCH.
[0204] Alternatively, the WTRU may be configured to monitor these
sequences for a specific instant of time, (e.g., periodically).
This may allow the network to save on transmission power.
[0205] In accordance with another embodiment, the WTRU may be
configured by the network, in addition to the conventional
E-HICH/E-RGCH set, to monitor a dedicated set of E-HICH/E-RGCH
conventional sequences that carry the UPCI information.
[0206] In accordance with another embodiment, a new feedback
channel, (will he referred to as "E-DCH channel stated information
channel (E-CSICH)") may be defined to signal the UPCI. In order to
have a minimum impact on legacy E-HICH/E-RGCH channels, a new type
of dedicated downlink feedback channel E-CSICH may be defined,
where a channelization code different from the one used by the
E-HICH/E-RGCH is used. The E-CSICH may use an orthogonal signature
sequence as in the E-HICH/E-RGCH as a means to allow multiple users
sharing the same channelization code and code multiplexing of UPCI
bits for a specific WTRU. The signature sequences may comprise a
set of orthogonal sequences with a length equal to one slot of the
subframe and the sequence may be repeated over multiple slots of
the subframe up to the duration of the E-CSICH.
[0207] Without loss of generality, in the following E-CSICH
examples, two WTRUs in a cell, each having 2-bit UPCI information,
are assumed as an example.
[0208] FIG. 32 shows an example transmitter 3200 for transmitting
UPCI for two WTRUs via an E-CSICH in accordance with one
embodiment. The transmitter 3200 includes UPCI mappers 3202, mixers
3204, repeaters 3206, a combiner 3208, and a channelization unit
3210. The two bits of UPCI for each WTRU are mapped to a certain
value by the UPCI mapper 3202, respectively. The two UPCI bits may
be generated once per TTI, (i.e., one output per 2 ms TTI). An
example mapping of the two bit UPCI to a complex value is shown in
Table 3. The mapped value of each WTRU is modulated with a
different M-bit long orthogonal sequence by the mixer 3204, and
then repeated over N times by the repeater 3206, where N may be 1
or higher integer. The resulting data for the two WTRUs are
combined by the combiner 3208 and spread with a channelization code
by the channelization unit 3210. With this embodiment, different
WTRUs may share the same E-CSICH by using different orthogonal
sequences.
TABLE-US-00003 TABLE 3 UPCI value Output of UPCI (decimal/binary)
mapper 0/00 1 + j 1/01 -1 + j 2/10 1 - j 3/11 -1 - j
[0209] FIG. 33 shows another example transmitter 3300 for
transmitting UPCI for two WTRUs via an E-CSICH in accordance with
another embodiment. In this embodiment, the UPCI information bits
of a specific WTRU is time-multiplexed and E-CSICHs for different
WTRUs are code-multiplexed. The transmitter 3300 includes mixers
3302, modulation mappers 3304, repeaters 3306, a combiner 3308, and
a channelization unit 3310. The UPCI information bits, (e.g., one
bit per slot), for each WTRU are modulated with a different
signature sequence by the mixer 3302, respectively, which generates
M bits per slot where M is the length of the signature sequence.
The binary information bits may be mapped to +1 and -1 before
applying a signature sequence. In this example, the two UPCI bits
are modulated over two slots. The M bits per slot are modulated,
(e.g., QPSK), by the modulation mapper 3304 and may be repeated
over N times by the repeater 3306, where N is 1 or higher integer.
The resulting two data are combined by the combiner 3308 and spread
with a channelization code by the channelization unit 3310.
[0210] FIG. 34 shows another example transmitter 3400 for
transmitting UPCI for two WTRUs via an E-CSICH in accordance with
another embodiment. In this embodiment, both UPCI information bits
of a specific WTRU and E-CSICHs for different WTRUs are
code-multiplexed. The transmitter 3400 includes mixers 3402,
modulation mappers 3404, combiners 3406, 3410, repeaters 3408, and
a channelization unit 3412. Each of the two UPCI bits for each WTRU
is modulated with a different M-bit long orthogonal sequence by the
mixer 3402. The binary information bits may be mapped to +1 and -1
before applying a signature sequence. The M bits are modulated by
the modulation mapper 3404, (e.g., QPSK). The modulated UPCI
signals for the same WTRU are combined by the combiner 3406, and
then may be repeated over N times by the repeater 3408, where N may
be 1 or higher integer. The resulting data for the two WTRUs are
combined by the combiner 3410 and spread with a channelization code
by the channelization unit 3412.
[0211] For M=40, the legacy 40-bit long signature sequences may be
reused for the orthogonal signature sequences. Alternatively, For
M=20, the following twenty 20-bit long sequences may be used as the
orthogonal signature sequences.
C ss , 20 = [ A A B C - B - C A A - A A C - B - C B - A A ]
##EQU00008## where ##EQU00008.2## A = [ - 1 1 1 1 1 1 - 1 1 1 1 1 1
- 1 1 1 1 1 1 - 1 1 1 1 1 1 - 1 ] ; ##EQU00008.3## B = [ 1 - 1 1 1
- 1 - 1 1 - 1 1 1 1 - 1 1 - 1 1 1 1 - 1 1 - 1 - 1 1 1 - 1 1 ] ;
##EQU00008.4## C = [ 1 1 - 1 - 1 1 1 1 1 - 1 - 1 - 1 1 1 1 - 1 - 1
- 1 1 1 1 1 - 1 - 1 1 1 ] . ##EQU00008.5##
[0212] In accordance with another embodiment, the pre-coding
weights may be indicated using the E-AGCH. The current 3GPP Release
6 E-AGCH carries up to 6 information bits (5 bits for the absolute
grant information and one bit for the absolute grant scope). In
accordance with one embodiment, a new E-AGCH structure may be
defined to carry the UPCI field in addition to the conventional
fields. When a WTRU receives an E-AGCH, the WTRU may use the UPCI
weights indicated in the E-AGCH until the next E-AGCH (with
potentially different set of UPCI weights to use). This embodiment
provides a solution with a small amount of downlink signaling.
[0213] In accordance with another embodiment, the absolute grant
field of the E-AGCH may be reduced from 5 bits to a smaller value,
(e.g., 3 bits), and the free bits may be used for the UPCI field.
This allows the network to use similar power level on the E-AGCH
and maintain the same level of reliability, at the expense of some
granularity on the absolute grant.
[0214] In accordance with another embodiment, the pre-coding
weights may be indicated using a high speed shared control channel
(HS-SCCH). Currently, an HS-SCCH order may be used for activation
and deactivation of DTX, discontinues reception (DRX), and
HS-SCCH-less operation, for high speed downlink shard channel
(HS-DSCH) serving cell change indication, and for the activation
and deactivation of secondary serving HS-DSCH cell and secondary
uplink frequency. When associated to a high speed physical downlink
shared channel (HS-PDSCH), the HS-SCCH carries control information
for demodulating the HS-PDSCH.
[0215] In accordance with one embodiment, the HS-SCCH order may be
used to carry the UPCI by introducing a new HS-SCCH order type. The
order bits (3-bits long) of the HS-SCCH may be used to carry the
UPCI. For example, any two of the 3 order bits, x.sub.ord,1,
x.sub.ord,2, x.sub.ord,3 may indicate 4 possible UPCI values.
Alternatively, all 3 order bits may be used to indicate up to 8
possible UPCI values to provide fine granularity of pre-coding
weights.
[0216] In accordance with another embodiment, as the WTRU needs to
monitor up to four HS-SCCHs, the decoded HS-SCCH number may
implicitly signal the UPCI. For example, if (the decoded HS-SCCH
number) MOD 4=0, 1, 2 and 3 may indicate 4 possible UPCI values,
respectively. In the case of multicarrier high speed downlink
packet access (MC-HSDPA) where more than one downlink carrier is
activated simultaneously, the HS-SCCH number may refer to the
HS-SCCH number carried on the DL carrier associated with the UL
carrier which the signaled UPCI will be applied to.
[0217] In accordance with another embodiment, the HS-SCCH type 1
and 3 physical channels may be used to signal the UPCI by using and
reinterpreting the unused field of the HS-SCCH. For example, 2 more
bits may be freed from the channelization code set bits
x.sub.ccs,1, X.sub.ccs,2, . . . , x.sub.ccs,7 by only signaling P
(15 codes need 4 bits) if O can be signaled via higher layer.
[0218] When the WTRU receives an HS-SCCH (either HS-SCCH order or
HS-SCCH physical channel), the WTRU may use the UPCI carried in the
HS-SCCH until the next HS-SCCH (with potentially different set of
UPCI weights to use).
[0219] In accordance with another embodiment, the pre-coding
weights may be indicated using a fractional dedicated physical
channel (F-DPCH). The current 3GPP Release 9 F-DPCH is designed to
carry up to 2 bits of TPC command every slot. By assigning a WTRU
specific timing offset or slot format, it is possible to multiplex
up to 10 WTRUs onto one channelization code for F-DPCH.
[0220] In accordance with one embodiment, a second F-DPCH may be
transmitted with a different channelization code to signal the
UPCI. Given the same time offset of the F-DPCHs, the two F-DPCHs
for the same WTRU may be transmitted with the same or different
F-DPCH slot format. For the second F-DPCH, the UPCI may be
transmitted every slot or every TTI, (e.g., 3 slots). If the UPCI
is updated every TTI, the same UPCI may be repeatedly transmitted
on 3 consecutive slots, or the updated UPCI may be transmitted on
one of the 3 slots and the unused 2 slots may be DTXed or used for
signaling the UPCI or TPC commands for other WTRUs.
[0221] Alternatively, given the same F-DPCH slot format, two
F-DPCHs transmitted to one WTRU may use the same time offset of the
F-DPCH for determining the uplink frame time. The two F-DPCHs
transmitted to one WTRU may use the different time offset.
[0222] Alternatively, a Node-B may transmit one F-DPCH to a WTRU
with a different F-DPCH format. FIG. 35 shows an F-DPCH format in
accordance with this embodiment. As shown in FIG. 35, both the TPC
field 3502 and the UPCI field 3504 are transmitted in one F-DPCH.
By appropriately assigning an F-DPCH slot format, it is possible to
time multiplex up to 5 WTRUs configured for uplink MIMO or less
than 10 WTRUs configured for MIMO or non-MIMO onto one
channelization code for F-DPCH.
[0223] The appropriate slot format should be configured for
different WTRUs to make sure that there is no overlap between a
UPCI field of one WTRU and a TPC field of the other WTRU. For
example, 5 odd-numbered slot formats may be configured, (i.e., the
F-DPCH slot format number=1, 3, 5, 7, 9) to 5 MIMO WTRUs onto one
channelization code for the F-DPCH.
[0224] Embodiments for the WTRU to select pre-coding weights are
disclosed hereafter.
[0225] In accordance with one embodiment, a WTRU may select the
pre-coding weights based on the received UPCI. The mapping between
the pre-coding weights and the UPCI may be pre-defined in the
specification. For example, the pre-coding weights may be mapped to
4 possible UPCI values, (i.e., w.sub.2.sup.pref), as shown in Table
4. In Table 4, the first pre-coding weight w.sub.1.sup.pref of the
preferred primary pre-coding vector (w.sub.1.sup.pref,
w.sub.2.sup.pref) is constant, and therefore, the 2-bit UPCI is
sufficient to indicate the pre-coding weight w.sub.2.sup.pref for
antenna 2. It should be understood that Table 2 is provided as an
example, and the mapping between pre-coding weights and the UPCI
may be set differently. For the single stream case, some
implementation issues such as power imbalance may happen for some
of the MIMO codebook. In order to mitigate this power imbalance
problem, a restriction may be applied on the uplink codebook choice
for the single stream case, (i.e., only a subset of preferred
precoding vectors w.sub.2.sup.pref may be used.
TABLE-US-00004 TABLE 4 w.sub.2.sup.pref UPCI value 1 + j 2
##EQU00009## 0 1 - j 2 ##EQU00010## 1 - 1 + j 2 ##EQU00011## 2 - 1
- j 2 ##EQU00012## 3
[0226] The WTRU may select the preferred primary pre-coding vector
(w.sub.1.sup.pref, w.sub.2.sup.pref) based on the UPCI from Node-B,
and then select the secondary pre-coding vector which may be a
unique function of the primary pre-coding vector. For example, the
secondary pre-coding vector may be selected to be orthogonal to the
primary pre-coding vector. Specifically, if a single transport
block is scheduled in a TTI, the WTRU may use the pre-coding vector
(w.sub.1.sup.pref, w.sub.2.sup.pref) for transmission of that
transport block. If two transport blocks are scheduled in a TTI,
the WTRU may use two orthogonal pre-coding vectors to transmit the
two transport blocks.
[0227] In accordance with another embodiment, the WTRU may select
the pre-coding weights based on the received full channel matrix or
eigen-value components of the channel matrix.
[0228] In accordance with another embodiment, the WTRU may select
the pre-coding weights based on one or more downlink (DL) control
signals and previous pre-coding weights, which may be treated as
the implicitly closed-loop transmit diversity scheme.
[0229] For a certain time duration, if the WTRU receives the DL
control information indicating the reliable transmission, the WTRU
may continue to use the same pre-coding weights as the previous
one. If the WTRU receives the DL control information indicating
unreliable transmission, the WTRU may select the pre-coding weights
which form the beam indicating the opposite direction of the
previous one. If the WTRU receives the DL control information
indicating a mix of reliable and unreliable transmissions, the WTRU
may select the pre-coding weights which may or may not be the same
pre-coding weights as the previous one.
[0230] More specifically, given three inputs: the pre-coding vector
used for last transmission (PV(n-1)), trigger, and trigger duration
(parameter "period"), the WTRU may select the pre-coding vector for
the coming transmission (PV(n)) by the generic feedback control
function as follows:
PV(n)=f(PV(n-1),trigger(n-period+1:n)), Equation(11)
where n is the time index of TTI or slot depending on the
pre-coding vector update rate, and trigger (n-period+1:n) denotes
the trigger that the WTRU has received for the time duration by
which the WTRU selects the pre-coding vector PV(n). The parameter
"period" may be pre-defined or configured by network.
[0231] The trigger may be based on any of the following control
signals: a received serving grant on DL E-AGCH/E-RGCH from a
Node-B, a TPC command pattern on DL DPCCH or F-DPCCH, the sequence
of positive acknowledgement (ACK), negative acknowledgement (NACK)
or DTX values received, for example, from the E-DCH serving cell, a
normalized remaining power margin (NRPM), WTRU power headroom
(instantaneous and/or averaged over longer period of time, for
example UE power headroom (UPH), and the like.
[0232] The function f (PV (n-1), trigger (n-period+1: n)) denotes
the generic feedback control scheme, by which the WTRU may select
the pre-coding vector PV(n) to be one of the following options
based on the pre-coding vector PV(n-1) used for the last
transmission and received triggers for last "period" time
duration.
[0233] Option A: the same pre-coding vector may be used
continuously as in the last transmission, (i.e.,
PV(n)=PV(n-1));
[0234] Option B: a new pre-coding vector PV(n) may be selected to
be opposite to the last pre-coding vector PV(n-1);
[0235] Option C: a new pre-coding vector PV(n) may be selected by
any of the following: (1) a default value configured by network,
(e.g., via radio resource control (RRC) signaling), (2) a default
value set in the specifications, a next pre-coding index (modulo
the number of elements in the codebook), (3) a previous pre-coding
vector index, (4) a random selection by any of the following:
uniformly distributed among all pre-coding vectors, uniformly
distributed among all other pre-coding vectors, uniformly
distributed among all other precoding vectors excluding the
orthogonal vector, and no particular distribution specified, (5)
the mostly used pre-coding vector in the past N time intervals,
where N may be any pre-defined or configured value, (6) the vector
orthogonal to the mostly used pre-coding vector in the past N time
intervals, (7) other vectors in UL MIMO pre-coding codebook except
the pre-coding vector selected by Option A or Option B, etc.
[0236] For initialization of the function f (PV (n-1), trigger
(n-period+1: n)), PV(0) may be pre-defined value in the
specifications, or configured by network via RRC signaling, or any
pre-code vector randomly selected in the UL MIMO codebook. For time
duration n=1, PV(n)=PV(0).
[0237] Example implementations of the above embodiment for
selecting the pre-coding vector using the function f (PV (n-1),
trigger (n-period+1: n)) are given below.
[0238] In the first example implementation, the WTRU may select the
pre-coding weights based on trigger 1, (i.e., based on the received
serving grant (SG) on the E-AGCH and the E-RGCH from the Node-B),
by using the following feedback control scheme. If the WTRU
receives continuously increased SG for a period, the WTRU may
select the PV(n) by Option A. If the WTRU receives continuously
decreased SG for a period, the WTRU may select the PV(n) by Option
B. If the WTRU receives alternatively increased and decreased SG
for a period, the WTRU may select the PV(n) by Option C.
[0239] In the second example implementation, the WTRU may select
the pre-coding weights based on trigger 2, (i.e., a TPC command
pattern on DL DPCCH/F-DPCCH from the Node-B), by using the
following feedback control scheme. If the WTRU receives
continuously decreased TPC command, (i.e., TPC_cmd=-1), for a
period, the WTRU may select the PV(n) by Option A. If the WTRU
receives continuously increased TPC commands, (i.e., TPC_cmd=1),
for a period, the WTRU may select the PV(n) by Option B. If the
WTRU receives alternatively increased and decreased TPC commands,
(e.g., TPC_cmd=1,-1,1,-1 . . . ), for a period, the WTRU may select
the PV(n) by Option C.
[0240] In the third example implementation, the WTRU may select the
pre-coding weights based on trigger 3, (i.e., the sequence of
ACK/NACK/DTX values received, for example, from the E-DCH serving
cell), by using the following feedback control scheme. If the WTRU
receives continuously ACK for a period, the WTRU may select the
PV(n) by Option A. If the WTRU receives continuously NACK for a
period, the WTRU may select the PV(n) by Option B. If the WTRU
receives ACK and NACK, or ACK, NACK, and DTX, alternately, (or
DTX), for a period, the WTRU may select the PV(n) by Option C.
[0241] In the fourth example implementation, the WTRU may select
the pre-coding weights based on trigger 4, (i.e., a NRPM), by using
the following feedback control scheme. If the WTRU determines
continuously increased NRPM for a period, the WTRU may select the
PV(n) by Option A. If the WTRU determines continuously decreased
NRPM for a period, the WTRU may select the PV(n) by Option B. If
the WTRU determines alternatively increased and decreased NRPM for
a period, the WTRU may select the PV(n) by Option C.
[0242] The pre-coding weights for the primary stream in a
dual-stream transmission may not be selected to be the same as the
weights for the single-stream transmission. This is due to the fact
that the weight generation for diversity may be different from the
one for spatial-multiplexing. Thus, the WTRU may have to select
from two sets of weights depending on the number of streams being
transmitted. For example, the Node-B may indicate to the WTRU two
sets of preferred weights: one set of preferred weights in case of
single-stream transmission and another set of weights for
dual-stream transmission. The WTRU, for example, may apply the
appropriate weights on a TTI by TTI basis depending on the number
of stream. This method may be applied to any weight selection
described above and below.
[0243] When WTRU is in soft handover, the pre-coder weights may be
selected based on the following two embodiments.
[0244] In accordance with a first embodiment, a radio network
controller (RNC) may emphasize the E-DCH serving cell to determine
the preferred pre-coding weights. In this case, all cells in the
active set reports their estimated channel matrix (or channel state
information (CSI)), to the RNC, and then the antenna weight vector
(W) may be determined by the RNC so as to maximize the criteria
function P:
P=W.sup.H(.alpha.(H.sub.1.sup.HH.sub.1)+(1-.alpha.)(H.sub.2.sup.HH.sub.2-
+ . . . ))W, Equation (12)
where H.sub.k is the estimated channel matrix at cell k, cell #1 is
the E-DCH serving cell, and coefficient .alpha. is the pre-defined
parameter that is less than or equal to 1. For example, .alpha.=0.7
to emphasize the serving cell performance. The UPCI may be feedback
to the WTRU to select the pre-coding weights.
[0245] In accordance with a second embodiment, the WTRU may use a
majority rule to select the pre-coding weights based on multiple
received UPCIs from different cells in the active set.
[0246] In accordance with a third embodiment, the WTRU may use the
pre-coding weights signaled by the serving E-DCH cell, or derived
from the serving E-DCH cell signals.
[0247] Embodiments for a WTRU to signal the pre-coding weights are
disclosed hereafter. After the selected pre-coding weights are
applied by the WTRU, the UL pre-coding vector may or may not be
signaled to the UTRAN. If the WTRU is not allowed to override the
signaled pre-coding weights by the Node-B, it is not necessary for
the WTRU to signal it. If the WTRU is allowed to override the
signaled pre-coding weights by the Node-B or the WTRU may determine
the preferred pre-coding weights, the WTRU needs to signal it to
the UTRAN.
[0248] The pre-coding weight information may be indicated by using
a different second pilot sequence pattern that is sent on an UL
DPCCH2. For example, in case where the DL MIMO pre-coding matrix is
reused for the UL MIMO, whose weights w.sub.1, w.sub.2, w.sub.3 and
w.sub.4 of the 2.times.2 pre-coding matrix are given by Equations
(12)-(14), 4 different pilot patterns are needed to map to 4
possible selection of w.sub.2. Alternatively, the pre-coding weight
information may be carried on a non-pilot field of the second UL
DPCCH, (i.e., DPCCH2). Alternatively, the pre-coding weight
information may be carried on the second UL E-DPCCH, (i.e.,
E-DPCCH2), by replacing the happy bit. Since the happy bit field
may carry 1 bit of information, this approach may in practice be
applicable to antenna switching, as an example. Additional
signaling or codeword restriction may be necessary if additional
information needs to be transmitted.
[0249] Embodiments for a Node-B to transmit channel state
information are explained hereafter.
[0250] Instead of the codebook index, a Node-B may feed back to the
WTRU quantized phase and amplitude/power offsets between two
transmit antennas of the WTRU. In addition, for spatial
multiplexing, the rank information needs to be fed back to the
WTRU. The embodiments for sending the UPCI disclosed above and/or
their combinations may be reused or extended to signal the channel
station information and/or the rank information. For example, the
E-CSICH may be used to send the index of quantized phase offset
indication (PHI), the index of power offset indication (POI), and
rank indication (RI).
[0251] Example transmitter structures of using E-CSICH to signal
the channel state information UPCI, PHI, POI, and RI for two MIMO
WTRUs are disclosed below. Without loss of generality, 2-bit UPCI,
2-bit PHI, 2-bit POI and 1-bit RI are assumed.
[0252] FIGS. 36 and 37 show signaling of PHI and POI using the
transmitter structure shown in FIGS. 32 and 34, respectively.
[0253] In FIG. 36, the transmitter 3600 includes PHI mappers 3602,
POI mappers 3603, mixers 3604, a combiner 3606, 3610, repeaters
3608, and a channelization unit 3610. The PHI bits and POI bits for
each WTRU are mapped to a certain value by the PHI mapper 3602 and
POI mapper 3603, respectively. The PHI and POI mappers 3602, 3603
may use the UPCI value mapping given in Table 3. The mapped value
of each WTRU is modulated with a different M-bit long orthogonal
sequence by the mixer 3604, and then combined by the combiner 3606,
and then repeated over N times by the repeater 3608, where N may be
1 or higher integer. The resulting data for the two WTRUs are
combined by the combiner 3610 and spread with a channelization code
by the channelization unit 3612.
[0254] The transmitter 3700 in FIG. 37 includes mixers 3702, 3703,
modulation mappers 3704, combiners 3706, 3710, repeaters 3708, and
a channelization unit 3712. The PHI and POI bits for each WTRU are
modulated with a different M-bit long orthogonal sequence by the
mixer 3702, 3703, respectively. The binary information bits may be
mapped to +1 and -1 before applying a signature sequence. The M
bits are modulated by the modulation mapper 3704, (e.g., QPSK). The
modulated UPCI signals for the same WTRU are combined by the
combiner 3706, and then may be repeated over N times by the
repeater 3708, where N may be 1 or higher integer. The resulting
data for the two WTRUs are combined by the combiner 3710 and spread
with a channelization code by the channelization unit 3712.
[0255] FIGS. 38 and 39 show signaling of UPCI and RI using the
transmitter structure shown in FIGS. 32 and 34, respectively. The
transmitter structure of FIGS. 38 and 39 are substantially similar
to the transmitter structure in FIGS. 36 and 37, respectively.
Therefore, the details of the transmitter structure in FIGS. 38 and
39 will not be explained for simplicity. Example RI mapping is
given in Table 5.
TABLE-US-00005 TABLE 5 RI value Output of RI Rank (decimal/binary)
mapper 1 1/0 1 + j 2 2/1 -1 + j
[0256] FIG. 40 shows an example frame format for the E-CSICH. For 2
ms TTI, the duration of the E-CSICH may be 2 ms, and for 10 ms TTI,
the duration of E-CSICH may be 10 ms.
[0257] The sequence b.sub.i,0, b.sub.i,1, . . . , b.sub.i,M-1
transmitted in slot i in FIG. 40 is given by
b.sub.i,j=aC.sub.ss,M,m(i)j, where `a` is the output of the
RI/UPCI/POI/PCI mapper for the transmitter structure in FIG. 32,
and a=+1/-1 for the transmitter structure in FIGS. 33 and 34. The
index m(i) in slot i may take value from 0 to M-1.
[0258] The E-AGCH may be used to carry the channel state
information. For example, for MIMO-capable WTRUs, the E-AGCH may
use a spreading factor of 128 so that CSI may be multiplexed with
absolute grant value and absolute grant scope.
[0259] Upon reception of the CSI at the receiver, the WTRU applies
the received values for transmission. The RI indicates how many
streams the WTRU may transmit in the next time interval, (e.g.,
until reception of a new RI). If the RI indicates dual-stream
transmission, the WTRU may transmit up to two transport blocks
simultaneously. The RI may be indicated to the MAC layer for E-TFC
selection which provides up to two transport blocks according to
the available grant, power and data. Alternatively, when the RI
indicates dual-stream transmission, the WTRU may multiplex coded
bits of a single transport block onto two physical streams.
[0260] The PHI and POI indicate the phase offset index and the
power offset index of the second antenna with respect to the first
antenna. The WTRU then determines the phase offset value (.phi.)
and the power offset value (.gamma.).
[0261] The WTRU may apply a unity weight to the first antenna
(w.sub.1=1) and calculates the weight for the second antenna
(w.sub.2) using one of the following equations, depending on the
actual meaning of the power offset.
w.sub.2= {square root over (.gamma.)}e.sup.i.phi.or Equation
(13)
w.sub.2=e.sup. {square root over (.gamma.)}+i.phi. Equation
(14)
[0262] Alternatively, the WTRU may calculate the weight for the
first and second antennas to have a unit transmission gain across
the two antennas. This may be achieved, for instance by normalizing
w.sub.i and w.sub.2 as calculated above using equations (19) and
(20) (using, without loss of generality, the first expression for
w.sub.2 above):
w 1 = 1 1 + .gamma. , and Equation ( 15 ) w 2 = .gamma. 1 + .gamma.
.PHI. . Equation ( 16 ) ##EQU00013##
[0263] The secondary pre-coding vector may then be calculated as
the orthogonal vector to the calculated primary pre-coding weight
as follows.
w 3 = - .gamma. 1 + .gamma. , and Equation ( 17 ) w 4 = 1 1 +
.gamma. .PHI. . Equation ( 18 ) ##EQU00014##
[0264] The whole unitary precoding matrix may be expressed as:
W = [ w 1 w 3 w 2 w 4 ] . Equation ( 19 ) ##EQU00015##
[0265] This approach allows maintaining a unitary precoding matrix
while having a non-zero power offset between the two antenna
elements thus potentially providing better performance.
[0266] Although features and elements are described above in
particular combinations, one of ordinary skill in the art will
appreciate that each feature or element can be used alone or in any
combination with the other features and elements. In addition, the
methods described herein may be implemented in a computer program,
software, or firmware incorporated in a computer-readable medium
for execution by a computer or processor. Examples of
computer-readable media include electronic signals (transmitted
over wired or wireless connections) and computer-readable storage
media. Examples of computer-readable storage media include, but are
not limited to, a read only memory (ROM), a random access memory
(RAM), a register, cache memory, semiconductor memory devices,
magnetic media such as internal hard disks and removable disks,
magneto-optical media, and optical media such as CD-ROM disks, and
digital versatile disks (DVDs). A processor in association with
software may be used to implement a radio frequency transceiver for
use in a WTRU, UE, terminal, base station, RNC, or any host
computer.
* * * * *