U.S. patent application number 14/828161 was filed with the patent office on 2015-12-10 for method and apparatus for performing inter-frequency and/or inter-radio access technology measurements.
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 Christopher R. Cave, Virgil Comsa, Joseph S. Levy.
Application Number | 20150358849 14/828161 |
Document ID | / |
Family ID | 43447014 |
Filed Date | 2015-12-10 |
United States Patent
Application |
20150358849 |
Kind Code |
A1 |
Cave; Christopher R. ; et
al. |
December 10, 2015 |
METHOD AND APPARATUS FOR PERFORMING INTER-FREQUENCY AND/OR
INTER-RADIO ACCESS TECHNOLOGY MEASUREMENTS
Abstract
Techniques for performing inter-frequency and/or inter-radio
access technology (RAT) measurements are disclosed. A
multi-receiver wireless transmit/receive unit (WTRU) may receive
downlink transmissions via a plurality of downlink carriers, of a
set of configured downlink carriers, simultaneously. The WTRU may
receive gap configuration information for at least one of the set
of configured downlink carriers. The WTRU may further perform
inter-frequency measurements on carriers outside of the set of
configured downlink carriers during a measurement gap in response
to the received gap configuration information. The WTRU may further
receive information that at least one of the set of configured
downlink carriers is to be disabled. The WTRU may then perform
measurements on the frequency of the disabled downlink carrier
without using measurement gaps. The WTRU may perform measurements
on the disabled carrier without measurement gaps maintaining a
status of the disabled carrier as disabled at a physical layer.
Inventors: |
Cave; Christopher R.;
(Montreal, CA) ; Levy; Joseph S.; (Merrick,
NY) ; Comsa; Virgil; (Montreal, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
InterDigital Patent Holdings, Inc. |
Wilmington |
DE |
US |
|
|
Assignee: |
InterDigital Patent Holdings,
Inc.
Wilmington
DE
|
Family ID: |
43447014 |
Appl. No.: |
14/828161 |
Filed: |
August 17, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13965682 |
Aug 13, 2013 |
9113351 |
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14828161 |
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12896414 |
Oct 1, 2010 |
8526888 |
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13965682 |
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61247628 |
Oct 1, 2009 |
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Current U.S.
Class: |
370/252 |
Current CPC
Class: |
H04W 36/0085 20180801;
H04W 24/10 20130101; H04W 24/02 20130101; H04W 36/14 20130101; H04W
36/0083 20130101 |
International
Class: |
H04W 24/10 20060101
H04W024/10 |
Claims
1. A wireless transmit/receive unit (WTRU) comprising: a processor
and a transceiver configured to receive data simultaneously using a
plurality of downlink carriers of a set of configured downlink
carriers; the processor and the transceiver further configured to
receive gap configuration information for at least one of the set
of configured downlink carriers; the processor and the transceiver
further configured to perform inter-frequency measurements on
carriers outside of the set of configured downlink carriers during
a measurement gap in response to the received gap configuration
information; the processor and the transceiver further configured
to receive information that at least one of the set of configured
downlink carriers is to be disabled; and the processor and the
transceiver further configured to perform measurements on a
frequency of the disabled downlink carrier without using
measurement gaps.
2. The WTRU of claim 1 wherein the processor and transceiver are
further configured to maintain a status of the disabled carrier as
disabled at a physical layer.
3. The WTRU of claim 1 wherein the measurement gaps are configured
on an unpaired downlink carrier and not on a paired downlink
carrier.
4. The WTRU of claim 1 wherein the processor and transceiver are
further configured to determine whether a trigger condition for the
inter-frequency measurements is met, and perform the
inter-frequency measurements on a condition that the trigger
condition is met.
5. The WTRU of claim 1 wherein the processor and transceiver are
further configured to determine whether a trigger condition for
performing measurements on a frequency of the disabled downlink
carrier without using measurement gaps is met, and perform the
measurements on a frequency of the disabled downlink carrier
without using measurement gaps on a condition that the trigger
condition is met.
6. The WTRU of claim 1 wherein the processor and transceiver are
further configured to detect a home Node-B (HNB) cell or a home
evolved HNB (eHNB) cell, transmit a proximity indication on a
condition that an identity of the detected HNB or eHNB cell is in a
list that the WTRU received from a network, and perform the
inter-frequency measurements on a frequency carrier of the detected
HNB or eHNB cell.
7. The WTRU of claim 1 wherein the processor and transceiver are
further configured to transmit an indication to a network of a
capability of the WTRU to perform inter-frequency measurements on
carriers outside of the set of configured downlink carriers during
a measurement gap.
8. The WTRU of claim 1 wherein the processor and transceiver are
further configured to transmit an indication to a network of a
capability of the WTRU to perform measurements on the frequency of
the disabled downlink carrier without using measurement gaps.
9. A method implemented in a wireless transmit/receive unit (WTRU)
for performing inter-frequency measurements, the method comprising:
receiving data simultaneously using a plurality of downlink
carriers of a set of configured downlink carriers; receiving gap
configuration information for at least one of the set of configured
downlink carriers; performing inter-frequency measurements on
carriers outside of the set of configured downlink carriers during
a measurement gap in response to the received gap configuration
information; receiving information that at least one of the set of
configured downlink carriers is to be disabled; and performing
measurements on a frequency of the disabled downlink carrier
without using measurement gaps.
10. The method of claim 9 further comprising: maintaining a status
of the disabled carrier as disabled at a physical layer.
11. The method of claim 9 wherein the measurement gaps are
configured on an unpaired downlink carrier and not on a paired
downlink carrier.
12. The method of claim 9 further comprising: determining whether a
trigger condition for the inter-frequency measurements is met, and
performing the inter-frequency measurements on a condition that the
trigger condition is met.
13. The method of claim 9 further comprising: determining whether a
trigger condition for performing measurements on a frequency of the
disabled downlink carrier without using measurement gaps is met,
and performing the measurements on a frequency of the disabled
downlink carrier without using measurement gaps on a condition that
the trigger condition is met.
14. The method of claim 9 further comprising: detecting a home
Node-B (HNB) cell or a home evolved HNB (eHNB) cell; transmitting a
proximity indication on a condition that an identity of the
detected HNB or eHNB cell is in a list that the WTRU received from
a network; and performing the inter-frequency measurements on a
frequency carrier of the detected HNB or eHNB cell.
15. The method of claim 9 further comprising: transmitting an
indication to a network of a capability of the WTRU to perform
inter-frequency measurements on carriers outside of the set of
configured downlink carriers during a measurement gap.
16. The method of claim 9 further comprising: transmitting an
indication to a network of a capability of the WTRU to perform
measurements on the frequency of the disabled downlink carrier
without using measurement gaps.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 13/965,682 filed Aug. 13, 2013, which is a
continuation of U.S. patent application Ser. No. 12/896,414 filed
Oct. 1, 2010, which issued as U.S. Pat. No. 8,526,888 on Sep. 3,
2013, which claims the benefit of U.S. Provisional Application Ser.
No. 61/247,628 filed Oct. 1, 2009, the contents of which are hereby
incorporated by reference herein.
BACKGROUND
[0002] Dual-cell high speed downlink packet access (HSDPA) has been
introduced in the third generation partnership project (3GPP)
Release 8 as part of the continuing evolution of high speed packet
access (HSPA) systems. This feature allows simultaneous downlink
(DL) transmission and reception on two adjacent carriers on the
high-speed channels. As part of 3GPP Release 9, the feature was
extended to support DL transmission and reception on non-adjacent
DL carriers, (e.g., carriers in different frequency bands). The
ability to support simultaneous reception on non-adjacent carriers
significantly impacts the radio frequency (RF) design of a wireless
transmit/receive unit (WTRU) including separate RF receivers.
[0003] In order to support inter-frequency and inter-radio access
technology (RAT) handovers, a WTRU performs measurements on other
frequencies and/or other RATs and report the measurements to the
radio access network. In case where a WTRU is equipped with a
single RF receiver, the WTRU performs the inter-frequency and/or
inter-RAT measurements during the measurement gaps. During the
measurement gaps, a downlink transmission to the WTRU is
interrupted, and the WTRU is allowed to tune its RF receiver to
other frequencies and/or RATs to perform the inter-frequency and/or
inter-RAT measurements. In 3GPP universal mobile telecommunication
systems (UMTS) wireless communications systems, these measurements
gaps are referred to as compressed mode (CM) gaps. In accordance
with the current 3GPP UMTS specification, both the DL reception and
the UL transmission are interrupted during the CM gaps, which
causes a degradation of service.
SUMMARY
[0004] A method and apparatus for performing inter-frequency and/or
inter-radio access technology (RAT) measurements are disclosed. A
multi-receiver wireless transmit/receive unit (WTRU) may receive
downlink transmissions via a plurality of downlink carriers
simultaneously. The WTRU may perform inter-frequency and/or
inter-RAT measurements using an inactive receiver without
measurement gaps if at least one receiver is inactive. If the WTRU
receives a measurement order on a disabled carrier, the WTRU may
perform measurements on the disabled carrier without measurement
gaps using an inactive receiver while maintaining a status of the
disabled carrier as disabled at a physical layer. The WTRU may
perform the performing the inter-frequency and/or inter-RAT
measurements autonomously on a condition that the trigger condition
is met and at least one receiver is inactive.
[0005] If all receivers are active, the WTRU may perform the
measurements using measurement gaps, wherein the measurement gaps
may be configured on a downlink carrier and not on an uplink
carrier, or alternatively, on an unpaired downlink carrier and not
on a paired downlink carrier, or alternatively, on a subset of
associated downlink uplink carrier pairs.
[0006] The WTRU may send a proximity indication on a condition that
the WTRU is near a detected home Node-B (HNB)/evolved HNB (eHNB)
cell whose identity is in a list, and perform inter-frequency
and/or inter-RAT measurements on a frequency carrier or an RAT of
the detected HNB/eHNB cell while configuring with at least one
receiver inactive and/or autonomous gaps.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] A more detailed understanding may be had from the following
description, given by way of example in conjunction with the
accompanying drawings wherein:
[0008] FIG. 1A is a system diagram of an example communications
system in which one or more disclosed embodiments may be
implemented;
[0009] 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;
[0010] 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;
[0011] FIG. 2 shows an example downlink (DL) and uplink (UL)
carrier configuration with measurement gaps on the DL carrier in
accordance with one embodiment;
[0012] FIG. 3 shows an example DL and UL carrier configuration with
measurement gaps on the DL carrier in accordance with another
embodiment;
[0013] FIG. 4 shows an example DL and UL carrier configuration with
measurement gaps on the DL carrier in accordance with an
alternative embodiment;
[0014] FIGS. 5A and 5B is a flow diagram of an example process for
autonomous inter-frequency and/or inter-RAT measurements in
accordance with one embodiment; and
[0015] FIGS. 6A and 6B is a flow diagram of an example process for
performing inter-frequency and/or inter-RAT measurements in
accordance with another embodiment.
DETAILED DESCRIPTION
[0016] 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.
[0017] 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.
[0018] 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.
[0019] 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.
[0020] 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).
[0021] 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).
[0022] 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).
[0023] 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.
[0024] 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.
[0025] 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.
[0026] 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.
[0027] 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.
[0028] 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
unit 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.
[0029] 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.
[0030] 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.
[0031] 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.
[0032] 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. For
example, the transceiver 120 may at least one RF transmitter and a
plurality of RF receivers so that the WTRU 102 may receive on two
or more adjacent or non-adjacent frequency carriers simultaneously.
This multi-receiver capability may be realized by implementing
multiple independent RF receivers, or by using a single advanced RF
receiver which is capable of processing multiple carriers, or by
any other means.
[0033] 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).
[0034] 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.
[0035] 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.
[0036] 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.
[0037] 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.
[0038] 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 RNC 142b. 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.
[0039] 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.
[0040] 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.
[0041] 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.
[0042] 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.
[0043] Hereafter, the embodiments will be described in the context
of 3GPP UMTS wireless communication systems. However, it should be
noted that the embodiments are applicable to any wireless
technologies where inter-frequency and/or inter-RAT measurements
are performed to support mobility including, but not limited to,
long term evolution (LTE), LTE-Advanced (LTE-A), WiMax, and any
other wireless communication systems.
[0044] Hereafter, the terminology "multi-receiver WTRU" will be
used to describe a WTRU that is capable of reception on two or more
adjacent or non-adjacent frequency carriers simultaneously. On the
transmit side, the multi-receiver WTRU may have a capability of
transmission either on a single frequency carrier or on two or more
adjacent or non-adjacent frequency carriers simultaneously. This
multi-receiver capability may be realized by implementing multiple
independent RF receivers, or by using a single advanced RF receiver
which is capable of processing multiple carriers, or by any other
means. Hereafter, the terminology "receiver" will be used to
describe a capability of the multi-receiver WTRU for receiving and
processing a single carrier either by an independent RF receiver or
by a single advanced receiver.
[0045] Embodiments for performing inter-frequency and/or inter-RAT
measurements where all receivers of the multi-receiver WTRU are
active are explained hereafter. One example of this case is when a
dual-band dual-cell HSDPA capable WTRU with two receivers is
configured to receive on two downlink carriers that are either
adjacent or non-adjacent.
[0046] In accordance with one embodiment, if at least one DL
carrier is configured without an associated UL carrier, the
measurement gaps, (e.g., compressed mode (CM) gaps), may be
configured on the DL, without any gap or interruption on the UL.
FIG. 2 shows an example DL and UL carrier configuration with
measurement gaps on the DL carrier in accordance with this
embodiment. In this example, a WTRU is configured with two DL
carriers and one UL carrier. The WTRU includes two receivers and
both receivers are active to process the two DL carriers. The first
DL carrier is associated with the single UL carrier, and the second
DL carrier is an unpaired carrier. As shown in FIG. 2, the
measurement gaps may be configured on the unpaired DL carrier,
without any measurement gaps on the UL carrier. Alternatively, the
measurement gaps may be configured both on the paired DL carrier
and its associated UL carrier, but not on the unpaired DL.
Additionally, it is possible that measurements gaps may be
configured on all of the DL and UL carriers or any allowable subset
of carriers. During the DL measurement gaps, the WTRU may perform
inter-frequency and/or inter-RAT measurements and the Node-B may
not schedule any transmissions to the WTRU on the DL carrier(s) on
which the measurement gaps are configured.
[0047] In accordance with another embodiment, if a measurement gap
is configured for a DL carrier that has an associated UL carrier,
the measurement gaps may be applied to both the UL and DL carriers,
(e.g., CM gaps are applied to the UL carrier as well), but the
measurement gaps may not be applied to all carriers, (i.e., on a
subset of associated downlink uplink carrier pairs).
[0048] FIG. 3 shows an example DL and UL carrier configuration with
measurement gaps on the DL carrier in accordance with this
embodiment. In this example, a WTRU is configured with two DL
carriers and two UL carriers. The WTRU includes two receivers and
both receivers are active to process the two DL carriers. The first
DL carrier is associated with the first UL carrier, and the second
DL carrier is associated with the second UL carrier. The
measurement gaps are configured on the second DL carrier, and the
WTRU may not transmit during the measurement gaps on the associated
UL carrier, (i.e., the second UL carrier in this example).
[0049] During the measurement gaps, a WTRU may perform
inter-frequency and/or inter-RAT measurements. The Node-B may not
schedule any transmissions to the WTRU on the carrier(s) on which
the measurement gaps are configured. The WTRU may apply the
conventional CM mode procedures to the associated UL carrier and
not transmit during the measurement gaps.
[0050] A combination of the above two embodiments may be
implemented in case where multiple DL carriers are configured for
measurement gaps and at least one DL carrier has an associated UL
carrier and at least one DL carrier does not. FIG. 4 shows an
example DL and UL carrier configuration with measurement gaps on
the DL carrier in accordance with an alternative embodiment. In
this example, a WTRU is configured with three DL carriers and two
UL carriers. The WTRU includes three receivers and all receivers
are active to process the three DL carriers. The first DL carrier
is associated with the first UL carrier, the second DL carrier is
associated with the second UL carrier, and the third DL carrier is
unpaired. The measurement gaps are configured on the second and
third DL carriers, and the WTRU may not transmit during the
measurement gaps on the second UL carrier, which is associated with
the second DL carrier.
[0051] For all of the embodiments above, the WTRU may determine the
carrier(s) configured for measurement gaps based on an explicit or
implicit indication from the network. The indication may be
received via a higher layer configuration message for configuring
the measurement gaps, (e.g., radio resource control (RRC) message
that carries the CM gap configuration information).
[0052] Alternatively, the carrier(s) selected for the measurement
gaps may be predetermined. For example, upon configuration of a
measurement gap, the WTRU may apply the measurement gaps to a
predetermined carrier, (e.g., a supplementary (or secondary)
carrier(s)), keeping other UL and DL carriers, (e.g., an anchor (or
primary) carrier(s)), in full transmission and reception mode. The
anchor (or primary) carrier may be defined as a carrier that
carries a specific set of control information for downlink/uplink
transmissions. Any carrier that is not assigned as an anchor (or
primary) carrier may be a supplementary (or secondary) carrier.
[0053] In case where multiple carriers may be selected for
measurement gaps, the carriers may be determined based on a
pre-defined pairing rule. For example, if two adjacent carriers are
configured in two different frequency bands, respectively, (i.e.,
total four carriers are configured), the measurement gaps may be
applied to all carriers within a specified frequency band, (e.g.,
the two adjacent carriers in one of the frequency bands in this
example).
[0054] The WTRU may be indicated to start performing the
inter-frequency and/or inter-RAT measurements on a particular
carrier by disabling that carrier. Disabling of the carrier(s) may
be indicated to the WTRU, for example, via a high speed shared
control channel (HS-SCCH) order or higher layer signaling, (e.g.,
RRC message), or any type of signaling or message at any protocol
layer. In case where a particular DL carrier(s) is disabled, the
WTRU may stop reception on the disabled carrier(s) and perform
inter-frequency and/or inter-RAT measurements using the available
receiver which were used for the disabled carrier(s).
[0055] Embodiments for performing inter-frequency and/or inter-RAT
measurements where at least one receiver of the multi-receiver WTRU
is inactive are explained hereafter. One example of this case is
when a dual-band dual-cell HSDPA capable WTRU with two receivers is
configured to operate with single carrier HSDPA.
[0056] In accordance with one embodiment, no measurement gaps may
be configured for the active receiver(s), and a WTRU may use the
inactive receiver(s) to perform the inter-frequency and/or
inter-RAT measurements. The WTRU may perform the inter-frequency
and/or inter-RAT measurements continuously using the inactive
receiver. In this case, no measurement gaps may be configured for
performing the inter-frequency and/or inter-RAT measurements.
[0057] Since the carrier activation and deactivation is controlled
by the Node-B, (e.g., via physical layer signaling, such as HS-SCCH
order), and the measurement gaps are scheduled by the radio network
controller (RNC) through an RRC message, the WTRU may receive the
inter-frequency and/or inter-RAT measurement order from the RNC on
the disabled carrier. In case where a DL carrier has been disabled
and the WTRU receives an indication with measurement gaps
configuration to perform the inter-frequency and/or inter-RAT
measurements on the disabled carrier, the WTRU may maintain the
state of the carrier as "disabled" at a physical layer (L1), and
perform the inter-frequency and/or inter-RAT measurements without
any measurement gaps using the receiver which had previously been
associated with that carrier or any other available receiver (a
receiver not assigned to an active channel).
[0058] If the disabled carrier is re-activated, (e.g., through L1
signaling such as an HS-SCCH order, or any other signaling or
message), so that all receivers become active, while the WTRU is
scheduled to perform the inter-frequency and/or inter-RAT
measurements on that disabled carrier, the WTRU may activate the DL
reception and/or UL transmission on that disabled carrier(s), and
may perform the inter-frequency and/or inter-RAT measurements in
accordance with any one of the embodiments disclosed above for the
case where all receivers are active.
[0059] In order to reduce the signaling load, the network may
preset a threshold(s) and a timer(s) and configure events for
starting and reporting the inter-frequency and/or inter-RAT
measurements such that a WTRU may autonomously start and report the
inter-frequency and/or inter-RAT measurements when at least one
receiver is inactive. In this embodiment, the WTRU may autonomously
start the inter-frequency and/or inter-RAT measurements once the
triggering condition(s) is met, and may not inform the network
about losing signal quality of the serving cell or the like in
order to get an inter-frequency/inter-RAT measurement order with or
without measurement gaps, thus speeding up the measurements
order/reporting cycle.
[0060] FIGS. 5A and 5B is a flow diagram of an example process 500
for autonomous inter-frequency and/or inter-RAT measurements in
accordance with one embodiment. A WTRU determines whether there is
at least one inactive receiver (502). If so, the WTRU determines
whether a trigger condition(s) is met (504). If either there is no
inactive receiver or the trigger condition(s) is not met, the WTRU
may not perform the autonomous measurements (520). If there is at
least one inactive receiver and the trigger condition(s) is met,
the WTRU may autonomously start the inter-frequency and/or
inter-RAT measurements and report the measurements to the network
(506). If the WTRU receives an activation order for a carrier(s)
(508) and there is no inactive receiver (510), the WTRU may stop
the autonomous inter-frequency/inter-RAT measurements on the
activated carrier(s), activate the reception and/or UL transmission
on that carrier(s), and may perform the inter-frequency and/or
inter-RAT measurements in accordance with any one of the
embodiments described above for the case where all receivers of the
WTRU are active (512).
[0061] If there is additional inactive receiver (510), it is
determined whether the additional inactive receiver is capable of
working on that carrier (514). If the determination at 514 is
positive, the WTRU may stop the autonomous inter-frequency and/or
inter-RAT measurements on that carrier, activate the DL reception
and/or UL transmission on that carrier, and configure and continue
measurements without measurement gaps with the available inactive
receiver if the trigger condition is still met (516).
[0062] If the determination at 514 is negative, the WTRU may stop
the autonomous inter-frequency and/or inter-RAT measurements and
wait for a higher layer configuration message for the measurement
request with measurement gaps on the active carriers, and perform
the inter-frequency and/or inter-RAT measurements in accordance
with any one of the embodiments disclosed above for the case that
all receivers are active (518).
[0063] A home Node-B (HNB) or an evolved HNB (eHNB) may be deployed
at customer premises to off-load traffics from the macro Node-B and
provide a better link quality and performance. An access to the
HNB/eHNB is based on the HNB/eHNB cell identity, called closed
subscriber group (CSG) identity (ID). For supporting mobility from
the macro Node-B to the HNB or eHNB, a WTRU may send a proximity
indication to the network when the WTRU detects that it is near a
HNB/eHNB cell whose CSG ID is in the list provided by the network.
The proximity indication may include the RAT and the frequency of
the detected HNB/eHNB cell. After receiving the proximity
indication, the network, (e.g., radio network controller (RNC)),
may configure measurement on the reported carrier or RAT to measure
the HNB/eHNB cell. Measurement gaps, (e.g., CM gaps), may be
activated to allow the WTRU to perform the measurements on the
reported frequency and RAT. The WTRU sends a measurement report to
the network, and the network may configure the WTRU to perform
system information (SI) acquisition and report SI. The WTRU may
perform SI acquisition using autonomous gaps. The autonomous gaps
are scheduled by the WTRU. The WTRU may suspend reception and
transmission with the serving cell to acquire the relevant SI from
the target HNB/eHNB.
[0064] In accordance with one embodiment, in case the WTRU is
capable of performing an autonomous search for a Node-B, (e.g., an
HNB or eHNB detection), the inter-frequency and/or inter-RAT
measurements may be started manually by the user. FIGS. 6A and 6B
is a flow diagram of an example process 600 for performing
measurements in accordance with one embodiment. A WTRU sends a
proximity indication to the network when the WTRU detects that it
is near a HNB/eHNB cell whose CSG ID is in the WTRU's list provided
by the network (602). After sending the proximity indication to the
Node-B, the WTRU may wait for gaps configuration from the network.
If the autonomous gaps are supported and all receivers of the WTRU
are active, the WTRU may perform the inter-frequency and/or
inter-RAT measurements in accordance with any embodiments disclosed
above for the case where all the receivers of the WTRU are active
while configuring the autonomous gaps appropriately (604). If one
or more receivers are available, no measurement gaps may be
required to start the inter-frequency and/or inter-RAT
measurements.
[0065] The WTRU receives an activation order for a carrier or a
receiver while performing autonomously the inter-frequency and/or
inter-RAT measurements (606). It is determined whether the
activation order is for the receiver capable of working on a
specific carrier/band, and whether other inactive receivers are
capable of working on that carrier/band (608).
[0066] If the determination at 608 is negative, it is further
determined whether the autonomous gaps are supported (610). If it
is determined so at step 610, the WTRU may stop the ongoing
inter-frequency and/or inter-RAT measurements, activate the DL
reception and/or UL transmission for the ordered carrier, send
autonomously the proximity report in order to get measurement gaps
configuration from the network, and upon receiving the gaps
configuration, the WTRU may perform the inter-frequency and/or
inter-RAT measurements based on any one of the embodiments
disclosed above for the case where all receivers of the WTRU are
active (612).
[0067] If the autonomous gaps are supported (610), the WTRU may
stop the ongoing inter-frequency and/or inter-RAT measurements,
activate the DL reception and/or UL transmission for the ordered
carrier, and configure autonomous gaps and continue the previous
measurements using one of the remaining receiver(s) (614).
[0068] If the determination at 608 is positive, the WTRU may stop
the ongoing measurements, activate the DL reception and/or UL
transmission for the ordered carrier, and continue measurements
without gaps using one of the inactive receivers (616).
[0069] The WTRU may indicate to the network its multi-receiver
capability, (e.g., capability of performing inter-frequency and/or
inter-RAT measurements while continuing transmission and reception
on one or more carriers). The WTRU may include a new capability
information element in a higher layer signaling, (e.g., RRC
message), to indicate the specific multi-receive capability.
[0070] Alternatively, the network may infer that the WTRU has such
multi-receiver capability from other capability indications of the
WTRU. For example, the network may infer that all WTRUs indicating
support of dual-band dual-cell HSDPA are also capable of performing
inter-frequency and/or inter-RAT measurements while continuing
transmission and reception on other carrier(s). Alternatively, a
new WTRU-class may be defined for WTRUs having the multi-receiver
capability.
[0071] The multi-receiver capability may not be supported at all
times by the network, and the network may selectively activate and
deactivate the multi-receiver capability of the WTRU. In accordance
with one embodiment, a WTRU may operate as required by the default
mode, (e.g., as required in the 3GPP Release 8), unless instructed
otherwise by the network. If the WTRU is instructed to operate with
the multi-receiver capability by the network, the WTRU may operate
in accordance with any embodiment disclosed herein.
[0072] Alternatively, a new type of configuration command, (e.g.,
an RRC message), may be defined to configure the WTRU to operate in
accordance with any one of the embodiments disclosed herein such
that once a WTRU receives this new type of configuration command,
the WTRU may perform the inter-frequency and/or inter-RAT
measurements and related operations in accordance with the
embodiments disclosed herein. Alternatively, the network may send
an activation command, (e.g., via RRC message), to enable the WTRU
to operate in accordance with the embodiments disclosed herein.
[0073] After handover to a target cell, the inter-frequency and/or
inter-RAT measurements and the related operations in accordance
with any embodiment disclosed herein may not be supported at the
target cell. In accordance with one embodiment, the WTRU may revert
to the default mode, (e.g., the operation in accordance with the
3GPP Release 8), until the WTRU is instructed otherwise.
Alternatively, the handover command may contain the necessary
configuration information, and the WTRU may configure itself as
directed by the handover command. Alternatively, the WTRU may be
network-aware and configure itself based on the capabilities of the
serving Node-B.
[0074] 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.
* * * * *