U.S. patent application number 17/357972 was filed with the patent office on 2021-11-18 for method and apparatus for triggering a beam state information report in a wireless communication system.
The applicant listed for this patent is ASUSTek Computer Inc.. Invention is credited to Richard Lee-Chee Kuo, Ming-Che Li, Ko-Chiang Lin.
Application Number | 20210359728 17/357972 |
Document ID | / |
Family ID | 1000005742070 |
Filed Date | 2021-11-18 |
United States Patent
Application |
20210359728 |
Kind Code |
A1 |
Li; Ming-Che ; et
al. |
November 18, 2021 |
METHOD AND APPARATUS FOR TRIGGERING A BEAM STATE INFORMATION REPORT
IN A WIRELESS COMMUNICATION SYSTEM
Abstract
Methods and apparatuses for beam management with user equipment
beam sweeping in a wireless communication system are disclosed
herein. In one method, a network node transmits a reference signal
for beam management within one occasion, wherein the occasion
comprises at least M symbol sets. The network node performs beam
sweeping for transmitting the reference signal in a first symbol
set of the M symbol sets. The network node repeats the beam
sweeping for transmitting the reference signal in the rest of the M
symbol sets.
Inventors: |
Li; Ming-Che; (Taipei City,
TW) ; Lin; Ko-Chiang; (Taipei City, TW) ; Kuo;
Richard Lee-Chee; (Taipei City, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ASUSTek Computer Inc. |
Taipei City |
|
TW |
|
|
Family ID: |
1000005742070 |
Appl. No.: |
17/357972 |
Filed: |
June 24, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15879790 |
Jan 25, 2018 |
11082095 |
|
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17357972 |
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62450467 |
Jan 25, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 72/1289 20130101;
H04B 7/0404 20130101; H04B 7/0632 20130101; H04B 7/063 20130101;
H04B 7/0417 20130101; H04B 7/0695 20130101; H04B 7/0686 20130101;
H04B 7/088 20130101; H04W 72/085 20130101 |
International
Class: |
H04B 7/0417 20060101
H04B007/0417; H04B 7/06 20060101 H04B007/06; H04B 7/08 20060101
H04B007/08 |
Claims
1. A method of a network node, the method comprising: transmitting
a reference signal for beam management within one occasion within a
single transmission period, wherein the one occasion is smaller
than the single transmission period and comprises M symbol sets;
performing beam sweeping for transmitting the reference signal in a
first symbol set of the M symbol sets; and repeating the beam
sweeping for transmitting the reference signal in the rest of the M
symbol sets.
2. The method of claim 1, wherein the beam sweeping includes
generating at least one beam for transmission in a first symbol of
a symbol set and then switching at least one beam for transmission
in a second symbol of the symbol set.
3. The method of claim 2, further including switching at least one
beam for transmission until a last symbol of the symbol set.
4. The method of claim 1, further including receiving a report
including a received power or quality of the reference signal from
a User Equipment (UE).
5. The method of claim 1, wherein a number of symbols in the M
symbol sets are the same.
6. The method of claim 1, wherein the reference signal is a
periodic reference signal.
7. The method of claim 6, wherein there is at least one occasion of
the periodic reference signal every transmission period.
8. The method of claim 1, wherein the reference signal is an
aperiodic reference signal.
9. The method of claim 8, wherein the aperiodic reference signal is
triggered for UE measurement or UE detection.
10. The method of claim 1, wherein there are multiple symbols in
each of the M symbol sets and the reference signal is transmitted
in all of the multiple symbols.
11. A network node, comprising: a processor; and a memory
operatively coupled to the processor, wherein the processor is
configured to execute a program code to: transmit a reference
signal for beam management within one occasion within a single
transmission period, wherein the one occasion is smaller than the
single transmission period and comprises M symbol sets; perform
beam sweeping for transmitting the reference signal in a first
symbol set of the M symbol set; and repeat the beam sweeping for
transmitting the reference signal in the rest of the M symbol
sets.
12. The network node of claim 11, wherein the beam sweeping
includes generating at least one beam for transmission in a first
symbol of a symbol set and then switching at least one beam for
transmission in a second symbol of the symbol set.
13. The network node of claim 12, further including switching at
least one beam for transmission until a last symbol of the symbol
set.
14. The network node of claim 11, wherein the network node receives
a report including a received power or quality of the reference
signal from a User Equipment (UE).
15. The network node of claim 11, wherein the number of symbols in
the M symbol sets are the same.
16. The network node of claim 11, wherein the reference signal is a
periodic reference signal.
17. The network node of 16, wherein there is at least one occasion
of the periodic reference signal every transmission period.
18. The network node of claim 11, wherein the reference signal is
an aperiodic reference signal.
19. The network node of claim 18, wherein the aperiodic reference
signal is triggered for UE measurement or UE detection.
20. The network node of claim 11, wherein there are multiple
symbols in each of the M symbol sets and the reference signal is
transmitted in all of the multiple symbols.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of U.S. patent
application Ser. No. 15/879,790, filed Jan. 25, 2018, which claims
priority to and the benefit of U.S. Provisional Patent Application
Ser. No. 62/450,467, filed on Jan. 25, 2017; with the entire
disclosure of each referenced application fully incorporated herein
by reference.
FIELD
[0002] This disclosure generally relates to wireless communication
networks, and more particularly, to a method and apparatus for beam
management with user equipment (UE) beamforming in a wireless
communication system.
BACKGROUND
[0003] With the rapid rise in demand for communication of large
amounts of data to and from mobile communication devices,
traditional mobile voice communication networks are evolving into
networks that communicate with Internet Protocol (IP) data packets.
Such IP data packet communication can provide users of mobile
communication devices with voice over IP, multimedia, multicast and
on-demand communication services.
[0004] An exemplary network structure is an Evolved Universal
Terrestrial Radio Access Network (E-UTRAN). The E-UTRAN system can
provide high data throughput in order to realize the above-noted
voice over IP and multimedia services. A new radio technology for
the next generation (e.g., 5G) is currently being discussed by the
3GPP standards organization. Accordingly, changes to the current
body of 3GPP standard are currently being submitted and considered
to evolve and finalize the 3GPP standard.
SUMMARY
[0005] Methods and apparatuses for beam management with user
equipment beam sweeping in a wireless communication system are
disclosed herein. In one method, a network node transmits a
reference signal for beam management within one occasion, wherein
the occasion comprises at least M symbol sets. The network node
performs beam sweeping for transmitting the reference signal in a
first symbol set of the M symbol sets. The network node repeats the
beam sweeping for transmitting the reference signal in the rest of
the M symbol sets.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 shows a diagram of a wireless communication system
according to one exemplary embodiment.
[0007] FIG. 2 is a block diagram of a transmitter system (also
known as access network) and a receiver system (also known as user
equipment or UE) according to one exemplary embodiment.
[0008] FIG. 3 is a functional block diagram of a communication
system according to one exemplary embodiment.
[0009] FIG. 4 is a functional block diagram of the program code of
FIG. 3 according to one exemplary embodiment.
[0010] FIG. 5A is an example of digital beamforming.
[0011] FIG. 5B is an example of analogue beamforming.
[0012] FIG. 5C is an example of hybrid beamforming, fully
connected.
[0013] FIG. 5D is an example of hybrid beamforming, sub-array.
[0014] FIG. 6 illustrates a beam concept in 5G as shown in 3GPP
R2-162709
[0015] FIG. 7 illustrates stand-alone, co-sited with LTE, and a
centralized baseband as shown in 3GPP R3-160947, TR 38.801
V0.1.0.
[0016] FIG. 8 illustrates a centralized baseband with low
performance transport and shared RAN as shown in 3GPP R3-160947, TR
38.801 V0.1.0.
[0017] FIG. 9 illustrates different deployment scenarios with a
single TRP cell as shown in 3GPP R2-163879.
[0018] FIG. 10 illustrates different deployment scenarios with
multiple TRP cells as shown in 3GPP R2-163879.
[0019] FIG. 11 illustrates one exemplary 5G cell as shown in 3GPP
R2-162210.
[0020] FIG. 12 illustrates one exemplary LTE cell and NR cell as
shown in 3GPP R2-163471.
[0021] FIG. 13 is a reproduction of Table 5.2-1 from KT 5G-SIG TS
5G.213 v1.9 illustrating BRRS resource allocation field for xPDCCH
with DL or UL DCI.
[0022] FIG. 14 is a reproduction of Table 5.2-2 from KT 5G-SIG TS
5G.213 v1.9 illustrating BRRS process indication field for xPDCCH
with DL or UL DCI.
[0023] FIG. 15 is a reproduction of Table 5.2-3 from KT 5G-SIG TS
5G.213 v1.9 illustrating BR process configuration.
[0024] FIG. 16 is a reproduction of Table 8.3.3.1-1 from KT 5G-SIG
TS 5G.213 v1.9 illustrating a 7-bit BRSRP Table.
[0025] FIG. 17 is a reproduction of Table 8.4.3.1-1 from KT 5G-SIG
TS 5G.213 v1.9 illustrating a 7-bit BRRS-RP mapping.
[0026] FIG. 18 is a reproduction of Table 8.4.3.2-1 from KT 5G-SIG
TS 5G.213 v1.9 illustrating BRRS-RI mapping.
[0027] FIG. 19 illustrates one example for a combination limitation
of beam generation.
[0028] FIG. 20 illustrates gain compensation by beamforming in
HF-NR system as shown in 3GPP R2-162251.
[0029] FIG. 21 illustrates weakened interference by beamforming in
HF-NR system as shown in 3GPP R2-162251.
[0030] FIG. 22 illustrates a table showing a maximum number of beam
training opportunities in one beam reference signal occasion.
[0031] FIG. 23 illustrates one embodiment of repetition patterns
for beam sweeping.
[0032] FIG. 24 illustrates one embodiment of repetition patterns
for beam sweeping.
[0033] FIG. 25 illustrates one embodiment of repetition patterns
for beam sweeping.
[0034] FIG. 26 illustrates one embodiment of repetition patterns
for beam sweeping.
[0035] FIG. 27 illustrates one embodiment of repetition patterns
for beam sweeping.
[0036] FIG. 28 is a flow diagram for one exemplary embodiment from
the perspective of a network.
[0037] FIG. 29 is a flow diagram for one exemplary embodiment from
the perspective of a UE.
DETAILED DESCRIPTION
[0038] The exemplary wireless communication systems and devices
described below employ a wireless communication system, supporting
a broadcast service. Wireless communication systems are widely
deployed to provide various types of communication such as voice,
data, and so on. These systems may be based on code division
multiple access (CDMA), time division multiple access (TDMA),
orthogonal frequency division multiple access (OFDMA), 3GPP LTE
(Long Term Evolution) wireless access, 3GPP LTE-A or LTE-Advanced
(Long Term Evolution Advanced), 3GPP2 UMB (Ultra Mobile Broadband),
WiMax, or some other modulation techniques.
[0039] In particular, the exemplary wireless communication systems
devices described below may be designed to support one or more
standards such as the standard offered by a consortium named "3rd
Generation Partnership Project" referred to herein as 3GPP,
including: R2-162366, "Beam Forming Impacts"; R2-163716,
"Discussion on terminology of beamforming based high frequency NR";
R2-162709, "Beam support in NR"; R2-162762, "Active Mode Mobility
in NR: SINR drops in higher frequencies"; R3-160947, TR 38.801
V0.1.0, "Study on New Radio Access Technology; Radio Access
Architecture and Interfaces"; R2-164306, "Summary of email
discussion [93bis#23][NR] Deployment scenarios"; RAN2#94 meeting
minutes; R2-162251, "RAN2 aspects of high frequency New RAT";
R2-163879, "RAN2 Impacts in HF-NR"; R2-162210, "Beam level
management<->Cell level mobility"; R2-163471, "Cell concept
in NR". Additionally, the exemplary wireless communications systems
devices may be designed to support the KT PyeongChang 5G Special
Interest Group (KT 5G-SIG) standards, including: TS 5G.213 v1.9,
"KT 5G Physical layer procedures (Release 1)"; TS 5G.321 v1.2, "KT
5G MAC protocol specification (Release 1)"; TS 5G.211 v2.6, "KT 5G
Physical channels and modulation (Release 1)" and TS 5G.331 v1.0,
"KT 5G Radio Resource Control (RRC) Protocol specification (Release
1)". The standards and documents listed above are hereby expressly
incorporated by reference in their entirety.
[0040] FIG. 1 shows a multiple access wireless communication system
according to one embodiment of the invention. An access network 100
(AN) includes multiple antenna groups, one including 104 and 106,
another including 108 and 110, and an additional including 112 and
114. In FIG. 1, only two antennas are shown for each antenna group,
however, more or fewer antennas may be utilized for each antenna
group. Access terminal 116 (AT) is in communication with antennas
112 and 114, where antennas 112 and 114 transmit information to
access terminal 116 over forward link 120 and receive information
from access terminal 116 over reverse link 118. Access terminal
(AT) 122 is in communication with antennas 106 and 108, where
antennas 106 and 108 transmit information to access terminal (AT)
122 over forward link 126 and receive information from access
terminal (AT) 122 over reverse link 124. In a FDD system,
communication links 118, 120, 124 and 126 may use different
frequency for communication. For example, forward link 120 may use
a different frequency then that used by reverse link 118.
[0041] Each group of antennas and/or the area in which they are
designed to communicate is often referred to as a sector of the
access network. In the embodiment, antenna groups each are designed
to communicate to access terminals in a sector of the areas covered
by access network 100.
[0042] In communication over forward links 120 and 126, the
transmitting antennas of access network 100 may utilize beamforming
in order to improve the signal-to-noise ratio of forward links for
the different access terminals 116 and 122. Also, an access network
using beamforming to transmit to access terminals scattered
randomly through its coverage causes less interference to access
terminals in neighboring cells than an access network transmitting
through a single antenna to all its access terminals.
[0043] An access network (AN) may be a fixed station or base
station used for communicating with the terminals and may also be
referred to as an access point, a Node B, a base station, an
enhanced base station, an evolved Node B (eNB), or some other
terminology. An access terminal (AT) may also be called user
equipment (UE), a wireless communication device, terminal, access
terminal or some other terminology.
[0044] FIG. 2 is a simplified block diagram of an embodiment of a
transmitter system 210 (also known as the access network) and a
receiver system 250 (also known as access terminal (AT) or user
equipment (UE) in a MIMO system 200. At the transmitter system 210,
traffic data for a number of data streams is provided from a data
source 212 to a transmit (TX) data processor 214.
[0045] In one embodiment, each data stream is transmitted over a
respective transmit antenna. TX data processor 214 formats, codes,
and interleaves the traffic data for each data stream based on a
particular coding scheme selected for that data stream to provide
coded data.
[0046] The coded data for each data stream may be multiplexed with
pilot data using OFDM techniques. The pilot data is typically a
known data pattern that is processed in a known manner and may be
used at the receiver system to estimate the channel response. The
multiplexed pilot and coded data for each data stream is then
modulated (i.e., symbol mapped) based on a particular modulation
scheme (e.g., BPSK, QPSK, M-PSK, or M-QAM) selected for that data
stream to provide modulation symbols. The data rate, coding, and
modulation for each data stream may be determined by instructions
performed by processor 230.
[0047] The modulation symbols for all data streams are then
provided to a TX MIMO processor 220, which may further process the
modulation symbols (e.g., for OFDM). TX MIMO processor 220 then
provides N.sub.T modulation symbol streams to N.sub.T transmitters
(TMTR) 222a through 222t. In certain embodiments, TX MIMO processor
220 applies beamforming weights to the symbols of the data streams
and to the antenna from which the symbol is being transmitted.
[0048] Each transmitter 222 receives and processes a respective
symbol stream to provide one or more analog signals, and further
conditions (e.g., amplifies, filters, and upconverts) the analog
signals to provide a modulated signal suitable for transmission
over the MIMO channel. N.sub.T modulated signals from transmitters
222a through 222t are then transmitted from N.sub.T antennas 224a
through 224t, respectively.
[0049] At receiver system 250, the transmitted modulated signals
are received by N.sub.R antennas 252a through 252r and the received
signal from each antenna 252 is provided to a respective receiver
(RCVR) 254a through 254r. Each receiver 254 conditions (e.g.,
filters, amplifies, and downconverts) a respective received signal,
digitizes the conditioned signal to provide samples, and further
processes the samples to provide a corresponding "received" symbol
stream.
[0050] An RX data processor 260 then receives and processes the
N.sub.R received symbol streams from N.sub.R receivers 254 based on
a particular receiver processing technique to provide N.sub.T
"detected" symbol streams. The RX data processor 260 then
demodulates, deinterleaves, and decodes each detected symbol stream
to recover the traffic data for the data stream. The processing by
RX data processor 260 is complementary to that performed by TX MIMO
processor 220 and TX data processor 214 at transmitter system
210.
[0051] A processor 270 periodically determines which pre-coding
matrix to use (discussed below). Processor 270 formulates a reverse
link message comprising a matrix index portion and a rank value
portion.
[0052] The reverse link message may comprise various types of
information regarding the communication link and/or the received
data stream. The reverse link message is then processed by a TX
data processor 238, which also receives traffic data for a number
of data streams from a data source 236, modulated by a modulator
280, conditioned by transmitters 254a through 254r, and transmitted
back to transmitter system 210.
[0053] At transmitter system 210, the modulated signals from
receiver system 250 are received by antennas 224, conditioned by
receivers 222, demodulated by a demodulator 240, and processed by a
RX data processor 242 to extract the reserve link message
transmitted by the receiver system 250. Processor 230 then
determines which pre-coding matrix to use for determining the
beamforming weights then processes the extracted message.
[0054] Turning to FIG. 3, this figure shows an alternative
simplified functional block diagram of a communication device
according to one embodiment of the invention. As shown in FIG. 3,
the communication device 300 in a wireless communication system can
be utilized for realizing the UEs (or ATs) 116 and 122 in FIG. 1 or
the base station (or AN) 100 in FIG. 1, and the wireless
communications system is preferably the LTE system. The
communication device 300 may include an input device 302, an output
device 304, a control circuit 306, a central processing unit (CPU)
308, a memory 310, a program code 312, and a transceiver 314. The
control circuit 306 executes the program code 312 in the memory 310
through the CPU 308, thereby controlling an operation of the
communications device 300. The communications device 300 can
receive signals input by a user through the input device 302, such
as a keyboard or keypad, and can output images and sounds through
the output device 304, such as a monitor or speakers. The
transceiver 314 is used to receive and transmit wireless signals,
delivering received signals to the control circuit 306, and
outputting signals generated by the control circuit 306 wirelessly.
The communication device 300 in a wireless communication system can
also be utilized for realizing the AN 100 in FIG. 1.
[0055] FIG. 4 is a simplified block diagram of the program code 312
shown in FIG. 3 in accordance with one embodiment of the invention.
In this embodiment, the program code 312 includes an application
layer 400, a Layer 3 portion 402, and a Layer 2 portion 404, and is
coupled to a Layer 1 portion 406. The Layer 3 portion 402 generally
performs radio resource control. The Layer 2 portion 404 generally
performs link control. The Layer 1 portion 406 generally performs
physical connections.
[0056] 3GPP standardization activities on next generation (i.e. 5G)
access technology have been launched since March 2015. The next
generation access technology aims to support the following three
families of usage scenarios for satisfying both the urgent market
needs and the more long-term requirements set forth by the ITU-R
IMT-2020: [0057] eMBB (enhanced Mobile Broadband) [0058] mMTC
(massive Machine Type Communications) [0059] URLLC (Ultra-Reliable
and Low Latency Communications).
[0060] An objective of the 5G study item on new radio access
technology is to identify and develop technology components needed
for new radio systems which should be able to use any spectrum band
ranging at least up to 100 GHz. Supporting carrier frequencies up
to 100 GHz brings a number of challenges in the area of radio
propagation. As the carrier frequency increases, the path loss also
increases.
[0061] As described in 3GPP R2-162366, in lower frequency bands
(e.g. current LTE bands<6 GHz) the required cell coverage may be
provided by forming a wide sector beam for transmitting downlink
common channels. However, utilizing wide sector beam on higher
frequencies (>>6 GHz) the cell coverage is reduced with same
antenna gain. Thus, in order to provide required cell coverage on
higher frequency bands, higher antenna gain is needed to compensate
the increased path loss. To increase the antenna gain over a wide
sector beam, larger antenna arrays (number of antenna elements
ranging from tens to hundreds) are used to form high gain
beams.
[0062] As a consequence, the high gain beams are narrow compared to
a wide sector beam so multiple beams for transmitting downlink
common channels are needed to cover the required cell area. The
number of concurrent high gain beams that access point is able to
form may be limited by the cost and complexity of the utilized
transceiver architecture. In practice, on higher frequencies, the
number of concurrent high gain beams is much less than the total
number of beams required to cover the cell area. In other words,
the access point is able to cover only part of the cell area by
using a subset of beams at any given time.
[0063] As described in 3GPP R2-163716, beamforming is a signal
processing technique used in antenna arrays for directional signal
transmission/reception. With beamforming, a beam can be formed by
combining elements in a phased array of antennas in such a way that
signals at particular angles experience constructive interference
while others experience destructive interference. Different beams
can be utilized simultaneously using multiple arrays of
antennas.
[0064] Beamforming can be categorized into three types of
implementation: digital beamforming, hybrid beamforming, and analog
beamforming. For digital beamforming, the beam is generated on the
digital domain. That is, the weighting of each antenna element can
be controlled by a baseband (e.g., connected to a transceiver unit
(TXRU)). Therefore, it is very easy to tune the beam direction of
each sub-band differently across the system bandwidth. Also,
changing beam direction from time to time does not require any
switching time between orthogonal frequency-division multiplexing
(OFDM) symbols. All beams whose directions cover the whole coverage
can be generated simultaneously. However, this structure requires
(almost) one-to-one mapping between the TXRU (transceiver/RF chain)
and the antenna element. This structure can become quite
complicated as the number of antenna element increases and the
system bandwidth increases let alone the existence of heat
problems. For analog beamforming, the beam is generated on the
analog domain, i.e. the weighting of each antenna element can be
controlled by an amplitude/phase shifter in the radiofrequency (RF)
circuit. Since the weighing is purely controlled by the circuit,
the same beam direction would apply on the whole system bandwidth.
Also, if beam direction is to be changed, switching time is
required. The number of beam generated simultaneous by an analog
beamforming depends on the number of TXRU. It is noted that for a
given size of an array, the increase of TXRU may decrease the
antenna element of each beam, such that a wider beam would be
generated. In short, analog beamforming could avoid the complexity
and heat problem of digital beamforming even though it is more
restricted in operation. Hybrid beamforming can be considered as a
compromise between analog and digital beamforming, in which the
beam can come from both analog and digital domain. The three types
of beamforming are shown in FIGS. 5A-5D.
[0065] Based on 3GPP R2-162709 and as shown in FIG. 6, an eNB may
have multiple Transmission/Reception Points (TRPs) (either
centralized or distributed). Each TRP can form multiple beams. The
number of beams and the number of simultaneous beams in the
time/frequency domain depend on the number of antenna array
elements and the radiofrequency (RF) at the TRP.
[0066] Potential mobility type for New RAT (NR) can be listed as
follows: intra-TRP mobility; inter-TRP mobility; and inter-NR eNB
mobility.
[0067] Based on 3GPP R2-162762, reliability of a system purely
relying on beamforming and operating in higher frequencies might be
challenging, since the coverage might be more sensitive to both
time and space variations. As a consequence of that the Signal to
Interference plus Noise Ratio (SINR) of that narrow link can drop
much quicker than in the case of LTE.
[0068] Using antenna arrays at access nodes with the number of
elements in the hundreds, fairly regular grid-of-beams coverage
patterns with tens or hundreds of candidate beams per node may be
created. The coverage area of an individual beam from such array
may be small, down to the order of some tens of meters in width. As
a consequence, channel quality degradation outside the current
serving beam area is quicker than in the case of wide area
coverage, as provided by LTE.
[0069] Based on 3GPP R3-160947, TR 38.801 V0.1.0, the scenarios
illustrated in FIGS. 7 and 8 should be considered for support by
the NR radio network architecture.
[0070] Based on 3GPP R2-164306, the following scenarios in terms of
cell layout for standalone NR are captured to be studied: macro
cell only deployment; heterogeneous deployment; and small cell only
deployment.
[0071] Based on 3GPP RAN2#94 meeting minutes, 1 NR eNB (e.g. called
gNB) corresponds to 1 or many TRPs. Two levels of network
controlled mobility: Radio Resource Control (RRC) driven at a
"cell" level, and Zero/Minimum RRC involvement (e.g. at Medium
Access Control (MAC)/Physical (PHY)).
[0072] FIGS. 9-12 show some example of the concept of a cell in 5G
NR. FIG. 9 shows a deployment with single TRP cell. FIG. 10 shows a
deployment with multiple TRP cell. FIG. 11 shows one 5G cell
comprising a 5G node with multiple TRPs. FIG. 12 shows a comparison
between a LTE cell and a NR cell.
[0073] KT has organized KT PyeongChang 5G Special Interest Group
(KT 5G-SIG) to realize the world's first 5G trial service at
PyeongChang 2018 Olympic Winter Games. KT had developed a version
of 5G common physical layer specification and the higher layer
(L2/L3) specification for pushing forward the development of the 5G
trial network. Three kinds of beamforming procedures are designed
for beamforming-based operation in physical layer as disclosed in
KT 5G-SIG TS 5G.213 v1.9.
[0074] Beamforming procedures in the KT 5G PHY specification are
described in KT 5G-SIG TS 5G.213 v1.9 as follows:
5 Beamforming procedures 5.1 Beam acquisition and tracking The
downlink transmitting beams are acquired from beam reference
signals. Up to 8 antenna ports are supported for beam reference
signal (BRS). A UE tracks downlink transmitting beams through the
periodic BRS measurements. The BRS transmission period is
configured by a 2 bit indicator in xPBCH. The BRS transmission
period is the necessary time to sweep the whole downlink beams
transmitted via BRS. The following BRS transmission periods are
supported: [0075] "00" Single slot (<5 ms): supportable for
maximum 7 downlink transmitting beams per antenna port [0076] "01"
Single subframe (=5 m): supportable for maximum 14 downlink
transmitting beams per antenna port [0077] "10" Two subframe (=10
ms): supportable for maximum 28 downlink transmitting beams per
antenna port [0078] "11" Four subframe (=20 ms): supportable for
maximum 56 downlink transmitting beams per antenna port UE
maintains a candidate beam set of 4 BRS beams, where for each beam
the UE records beam state information (BSI). BSI comprises beam
index (BI) and beam reference signal received power (BRSRP). UE
reports BSI on PUCCH or PUSCH as indicated by 5G Node per clause
8.3. 5GNode may send BSI request in DL DCI, UL DCI, and RAR grant.
When reporting BSI on xPUCCH, UE reports BSI for a beam with the
highest BRSRP in the candidate beam set. When reporting BSI on
xPUSCH, UE reports BSIs for NE{1,2,4} beams in the candidate beam
set, where N is provided in the 2-bit BSI request from 5G Node. The
BSI reports are sorted in decreasing order of BRSRP. 5.1.1 BRS
management There are two beam switch procedures, which are MAC-CE
based beam switch procedure and DCI based beam switch procedure
associated with BRS. For the MAC-CE based beam switch procedure
[4], 5G Node transmits a MAC-CE containing a BI to the UE. The UE
shall, upon receiving the MAC-CE, switch the serving beam at the UE
to match the beam indicated by the MAC-CE. The beam switching shall
apply from the beginning of subframe n+kbeamswitch-delay-mac where
subframe n is used for HARQ-ACK transmission associated with the
MAC-CE and kbeamswitch-delay-mac=14. The UE shall assume that the
5G Node beam associated with xPDCCH, xPDSCH, CSI-RS, xPUCCH,
xPUSCH, and xSRS is switched to the beam indicated by the MAC-CE
from the beginning of subframe n+kbeam-switch-delay-mac. For the
DCI based beam switch procedure, 5G Node requests a BSI report via
DCI and the beam_switch_indication field is set to 1 in the same
DCI. The UE shall, upon receiving such a DCI, switch the serving
beam at the UE to match the beam indicated by the first BI reported
by the UE in the BSI report corresponding to this BSI request. The
beam switching shall apply from the beginning of subframe
n+kbeam-switch-delay-dic where subframe n is used for sending the
BSI report and kbeam-switch-delay-dci=11. If beam_switch_indication
field=0 in the DCI the UE is not required to switch the serving
beam at the UE. For any given subframe, if there is a conflict in
selecting the serving beam at the UE, the serving beam is chosen
that is associated with the most recently received subframe
containing the MAC-CE (for MAC-CE based procedure) or the DCI (for
DCI based procedure). A UE is not expected to receive multiple
requests for beam switching in the same subframe. 5.2 Beam
refinement BRRS is triggered by DCI. A UE can also request BRRS
using SR [4]. To request the serving 5G Node to transmit BRRS, the
UE transmits the scheduling request preamble where the higher layer
configured preamble resource {u,v,f', and NSR} is dedicated for
beam refinement reference signal initiation request. The time and
frequency resources that can be used by the UE to report Beam
Refinement Information (BRI), which consists of BRRS Resource Index
(BRRS-RI) and BRRS reference power (BRRS-RP), are controlled by the
5G Node. A UE can be configured with 4 Beam Refinement (BR)
processes by higher layers. A 2-bit resource allocation field and a
2 bit process indication field in the DCI are described in Table
5.2-1 and Table 5.2-2, respectively. FIG. 13 (reproduction of Table
5.2-1 from KT 5G-SIG TS 5G.213 v1.9). FIG. 14 (reproduction of
Table 5.2-2 from KT 5G-SIG TS 5G.213 v1.9). A BR process comprises
of up to eight BRRS resources, a resource allocation type and a
VCID, and is configured via RRC signalling. A BRRS resource
comprises of a set of antenna ports to be measured. FIG. 15
(reproduction of Table 5.2-3 from KT 5G-SIG TS 5G.213 v1.9). A BRRS
transmission can span 1, 2, 5 or 10 OFDM symbols, and is associated
with a BRRS resource allocation, BRRS process indication, and a BR
process configuration as in Table 5.2-1, 1, 5.2.-2 and 5.2.-3. A
BRI reported by the UE corresponds to one BR process that is
associated with up to eight BRRS resources. The UE shall assume
that BRRS mapped to the BRRS resource ID 0 in each BRRS process is
transmitted by the serving beam. 5.2.1 BRRS management There are
two beam switch procedures, which are MAC-CE based beam switch
procedure and DCI based beam switch procedure associated with BRRS.
For the MAC-CE based beam switch procedure [4], 5G Node transmits a
MAC-CE containing a BRRS resource ID and the associated BR process
ID to the UE. The UE shall, upon receiving the MAC-CE, switch the
serving beam at the UE to match the beam indicated by the MAC-CE.
The beam switching shall apply from the beginning of subframe
n+kbeamswitch-delay-mac where subframe n is used for HARQ-ACK
transmission associated with the MAC-CE and
kbeamswitch-delay-mac=14. The UE shall assume that the 5G Node beam
associated with xPDCCH, xPDSCH, CSI-RS, xPUCCH, xPUSCH, and xSRS is
switched to the beam indicated by the MAC-CE from the beginning of
subframe n+kbeam-switch-delay-mac. For the DCI based beam switch
procedure, 5G Node requests a BRI report via DCI and the
beam_switch_indication field is set to 1 in the same DCI. The UE
shall, upon receiving such a DCI, switch the serving beam at the UE
to match the beam indicated by the first BRRS-RI reported by the UE
in the BRI report corresponding to this BRI request. The beam
switching shall apply from the beginning of subframe
n+kbeam-switch-delay-dic where subframe n is used for sending the
BRI report and kbeam-switch-delay-dci=11. If beam_switch_indication
field=0 in the DCI the UE is not required to switch the serving
beam at the UE. For any given subframe, if there is a conflict in
selecting the serving beam at the UE, the serving beam is chosen
that is associated with the most recently received subframe
containing the MAC-CE (for MAC-CE based procedure) or the DCI (for
DCI based procedure). A UE is not expected to receive multiple
requests for beam switching in the same subframe.
5.3 Beam Recovery
[0079] If a UE detects the current serving beam is misaligned [4]
and has BSIs for beam recovery, the UE shall perform beam recovery
process. In the UL synchronized UE case, the UE transmits
scheduling request by scheduling request preamble where the
preamble resource {u, v, f' and N.sub.SR} is dedicated for beam
recovery as configured by higher layers. Upon the reception of this
request, 5G Node may initiate BSI reporting procedure as described
in section 8.3. In UL asynchronized UE case, the UE transmits
random access preamble for contention based random access. If the
UE is scheduled by RAR triggering BSI reporting, the UE reports N
BSIs in Msg3 as UCI multiplexing in [3]. < . . . > 8.3 UE
procedure for reporting Beam State Information (BSI) UE reports BSI
on xPUCCH or xPUSCH as indicated by 5G Node. 5G Node can send BSI
request in DL DCI, UL DCI, and RAR grant. If a UE receives BSI
request in DL DCI, the UE reports a BSI on xPUCCH. The
time/frequency resource for xPUCCH is indicated in the DL DCI. When
reporting BSI on xPUCCH, UE reports a BSI for a beam with the
highest BRSRP in the candidate beam set. If UE receives BSI request
in UL DCI or in RAR grant, UE reports BSIs on xPUSCH. The
time/frequency resource for xPUSCH is indicated in the UL DCI or
RAR grant that requests BSI report. When reporting BSI on xPUSCH,
UE reports BSI for N .di-elect cons. {1,2,4} beams with the highest
BRSRP in the candidate beam set, where N is provided in the DCI. If
BSI reporting is indicated on both xPUCCH and xPUSCH in the same
subframe, UE reports BSI on xPUSCH only and discards the xPUCCH
trigger. 8.3.1 BSI reporting using xPUSCH Upon decoding in subframe
n an UL DCI with a BSI request, UE shall report BSI using xPUSCH in
subframe n+4+m+l, where parameters m=0 and l={0, 1, . . . 7} is
indicated by the UL DCI. The number of BSIs to report, N .di-elect
cons. {1,2,4}, is indicated in UL DCI. A UE shall report N BSIs
corresponding to N beams in the candidate beam set. A BSI report
contains N BIs and corresponding BRSRPs. A UE shall report wideband
BRSRPs. A UE is not expected to receive more than one request for
BSI reporting on xPUSCH for a given subframe. 8.3.2 BSI reporting
using xPUCCH Upon decoding in subframe n a DL DCI with a BSI
request, UE shall report BSI using xPUCCH subframe index n+4+m+k,
where parameters m=0 and k={0, 1, . . . 7} is indicated by the DL
DCI. When reporting BSI on xPUCCH, UE reports BSI for a beam with
the highest BRSRP in the candidate beam set. A BSI report contains
BI and corresponding BRSRP. A UE shall report wideband BRSRP. A UE
is not expected to receive more than one request for BSI reporting
on xPUCCH for a given subframe. 8.3.3 BSI definition 8.3.3.1 BRSRP
definition The BRSRP indices and their interpretations are given in
Table 8.3.3.1-1. The reporting range of BRSRP is defined from -140
dBm to -44 dBm with 1 dB resolution as shown in Table 8.3.3.1-1.
The UE shall derive BRSRP values from the beam measurements based
on BRS defined in 5G.211. The UE shall derive BRSRP index from the
measured BRSRP value. Each BRSRP index is mapped to its
corresponding binary representation using 7 bits. FIG. 16
(reproduction of Table 8.3.3.1-1 from KT 5G-SIG TS 5G.213 v1.9).
8.3.3.2 Beam index definition BI indicates a selected beam index.
The BI is the logical beam index associated with antenna port, OFDM
symbol index and BRS transmission period [2], which is indicated by
9 bits. 8.4 UE procedure for reporting Beam Refinement Information
(BRI) 8.4.1 BRI reporting using xPUSCH If the uplink DCI in
subframe n indicates a BRRS transmission, the BRRS is allocated in
subframe n+m where m={0, 1, 2, 3} is indicated by a 2 bit RS
allocation timing in the DCI. A BRI report is associated with one
BR process that is indicated in the uplink DCI for the UE. Upon
decoding in subframe n an UL DCI with a BRI request, the UE shall
report BRI using xPUSCH in subframe n+4+m+l, where parameters m={0,
1, 2, 3} and l={0, 1, . . . 7} are indicated by the UL DCI. A UE
shall report wideband BRRS-RP values and BRRS-RI values
corresponding to the best NBRRS BRRS resource ID where NBRRS is
configured by higher layers If the number of configured BRRS
resource ID associated with the BR process is less than or equal to
NBRRS then the UE shall report BRRS-RP and BRRS-RI corresponding to
all the configured BRRS resources. A UE is not expected to receive
more than one BRI report request for a given subframe. 8.4.2 BRI
reporting using xPUCCH If the DL DCI in subframe n indicates a BRRS
transmission, the BRRS is allocated in subframe n+m where m={0, 1,
2, 3} is indicated by the DL DCI. A BRI report is associated with
one BRRS process that is indicated in the downlink DCI for the UE.
Upon decoding in subframe n a DL DCI with a BRI request, the UE
shall report BRI using xPUCCH in subframe n+4+m+k, where parameters
m={0, 1, 2, 3} and k={0, 1, . . . 7} are indicated by the DL DCI. A
UE shall report a wideband BRRS-RP value and a BRRS-RI value
corresponding to the best BRRS resource ID. A UE is not expected to
receive more than one BRI report request for a given subframe.
8.4.3.1 BRRS-RP definition The reporting range of BRRS-RP is
defined from -140 dBm to -44 dBm with 1 dB resolution. The mapping
of BRRS-RP to 7 bits is defined in Table 8.4.3.1-1. Each BRRS-RP
index is mapped to its corresponding binary representation using 7
bits. FIG. 17 (reproduction of Table 8.4.3.1-1 from KT 5G-SIG TS
5G.213 v1.9). 8.4.3.2 BRRS-RI definition BRRS-RI indicates a
selected BRRS resource ID. A BR process may comprise of a maximum
of 8 BRRS resource IDs. The selected BRRS resource ID is indicated
by 3 bits as in Table 8.4.3.2-1. FIG. 18 (reproduction of Table
8.4.3.2-1 from KT 5G-SIG TS 5G.213 v1.9).
[0080] Beamforming management in L2 layer is described in KT 5G-SIG
TS 5G.321 v1.2 as follows:
5.5 Beam management 5.5.1 Beam feedback procedure The beam feedback
procedure is used to report beam measurement results to the serving
cell. There are two beam feedback procedures defined one based on
measurement of beam reference signal (BRS), beam state information
reporting below, and one based on measurement of beam refinement
reference signal (BRRS), beam refinement information reporting
below. 5.5.1.1 Beam state information reporting The BRS-based beam
state information (BSI) reports initiated by xPDCCH order are
transmitted through UCI on xPUCCH/xPUSCH as scheduled by the
corresponding DCI[1]; event triggered BSI reports are transmitted
through BSI Feedback MAC Control Element defined in subclause
6.1.3.11 using normal SR or contention-based RACH procedure, where
BSI consists of Beam Index (BI) and beam reference signal received
power (BRSRP). BSI reports are based on BRS transmitted by the
serving cell. 5.5.1.1.1 BSI reporting initiated by xPDCCH order The
BSI reports initiated by xPDCCH order are based on the latest
measurement results obtained from the 5G physical layer. [0081] if
an xPDCCH order which requests BSI reporting through UCI via xPUCCH
by serving cell is received in this TTI: [0082] if the serving beam
is not the best beam and the BRSRP of the best beam is higher than
BRSRP of the serving beam: [0083] instruct the 5G physical layer to
signal the best beam on the scheduled UCI resource via xPUCCH as
defined in [1]; [0084] else: [0085] instruct the 5G physical layer
to signal the serving beam on the scheduled UCI resource via xPUCCH
as defined in [1]; [0086] if an xPDCCH order which requests BSI
reporting through UCI via xPUSCH by serving cell is received in
this TTI: [0087] if the number of BSI for reports requested equals
to 1: [0088] if the serving beam is not the best beam and the BRSRP
of the best beam is higher than BRSRP of the serving beam: [0089]
instruct the 5G physical layer to signal the best beam on the
scheduled UCI resource via xPUSCH as defined in [1]; [0090] else:
[0091] instruct the 5G physical layer to signal the serving beam on
the scheduled UCI resource via xPUSCH as defined in [1]; [0092]
else if the number of BSI reports requested is higher than 1 and:
[0093] if the serving beam is not the best beam and the BRSRP of
the best beam is higher than BRSRP of the serving beam: [0094]
instruct the 5G physical layer to signal N BSIs report with the
best beam as the first BSI and the next N-1 highest BRSRP beam
values on the scheduled UCI resource via xPUSCH; [0095] else:
[0096] instruct the 5G physical layer to signal N BSIs report with
the serving beam as the first BSI and the next N-1 highest BRSRP
beam values on the scheduled UCI resource via xPUSCH; 5.5.1.1.2 BSI
reporting initiated by 5G-MAC The BSI reports initiated by 5G-MAC
are based on an event trigger. [0097] if the BRSRP of the best beam
is higher than beamTriggeringRSRPoffset dB+the BRSRP of the serving
beam and: [0098] if the UE is uplink synchoronized (i.e.,
timeAlignmentTimer is not expired) [0099] UE transmits BSI Feedback
MAC Control Element on the UL resource granted through normal SR
procedure; [0100] else: [0101] UE transmits BSI Feedback MAC
Control Element on the UL resource for Msg3 granted through
contention-based random access procedure;
[0102] The following terminology may be used hereafter in the
detailed description: [0103] BS: a network central unit or a
network node in NR which is used to control one or multiple TRPs
which are associated with one or multiple cells. Communication
between BS and TRP(s) is via fronthaul. BS could also be referred
to as central unit (CU), eNB, gNB, or NodeB. [0104] TRP: a
transmission and reception point provides network coverage and
directly communicates with UEs. TRP could also be referred to as
distributed unit (DU) or network node. [0105] Cell: a cell is
composed of one or multiple associated TRPs, i.e. coverage of the
cell is composed of coverage of all associated TRP(s). One cell is
controlled by one BS. A cell could also be referred to as a TRP
group (TRPG). [0106] Beam sweeping: in order to cover all possible
directions for transmission and/or reception, a number of beams is
required. Since it is not possible to generate all these beams
concurrently, beam sweeping means to generate a subset of these
beams in one time interval and change generated beam(s) in other
time interval(s), i.e. changing beam in time domain. So, all
possible directions can be covered after several time intervals.
[0107] Beam sweeping number: necessary number of time interval(s)
to sweep beams in all possible directions once for transmission
and/or reception. In other words, a signaling applying beam
sweeping would be transmitted "beam sweeping number" of times
within one time period, e.g. the signaling is transmitted in (at
least partially) different beam(s) in different times of the time
period. [0108] Serving beam: serving beam for a UE is a beam
generated by a network node, e.g. TRP, which is currently used to
communicate with the UE, e.g. for transmission and/or reception.
[0109] Candidate beam: candidate beam for a UE is a candidate of a
serving beam. Serving beam may or may not be candidate beam. [0110]
Qualified beam: qualified beam is a beam with radio quality, based
on measuring signal on the beam, better than a threshold. [0111]
The best serving beam: The serving beam with the best quality (e.g.
the highest Beam Reference Signal Received Power (BRSRP) value).
[0112] The worst serving beam: The serving beam with the worst
quality (e.g. the worst BRSRP value). [0113] The following
assumptions for network side may be used hereafter in the detailed
description: [0114] NR using beamforming could be standalone, i.e.
UE can directly camp on or connect to NR. [0115] NR using
beamforming and NR not using beamforming could coexist, e.g. in
different cells. [0116] TRP would apply beamforming to both data
and control signaling transmissions and receptions, if possible and
beneficial. [0117] Number of beams generated concurrently by TRP
depends on TRP capability, e.g. maximum number of beams generated
concurrently by different TRPs may be different. [0118] Beam
sweeping is necessary, e.g. for the control signaling to be
provided in every direction. [0119] (For hybrid beamforming) TRP
may not support all beam combinations, e.g. some beams could not be
generated concurrently. FIG. 19 shows an example for combination
limitation of beam generation. [0120] Downlink timing of TRPs in
the same cell are synchronized. [0121] RRC layer of network side is
in a Base Station (BS). [0122] TRP should support both UEs with UE
beamforming and UEs without UE beamforming, e.g. due to different
UE capabilities or UE releases. The following assumptions for UE
side may be used hereafter in the detailed description: [0123] UE
may perform beamforming for reception and/or transmission, if
possible and beneficial. [0124] Number of beams generated
concurrently by UE depends on UE capability, e.g. generating more
than one beam is possible. [0125] Beam(s) generated by UE is wider
than beam(s) generated by TRP, gNB, or eNB. [0126] Beam sweeping
for transmission and/or reception is generally not necessary for
user data but may be necessary for other signaling, e.g. to perform
measurement. [0127] (For hybrid beamforming) UE may not support all
beam combinations, e.g. some beams could not be generated
concurrently. FIG. 19 shows an example for combination limitation
of beam generation. [0128] Not every UE supports UE beamforming,
e.g. due to UE capability or UE beamforming is not supported in NR
first (few) release(s). [0129] One UE is possible to generate
multiple UE beams concurrently and to be served by multiple serving
beams from one or multiple TRPs of the same cell. [0130] Same or
different (downlink (DL) or uplink (UL)) data could be transmitted
on the same radio resource via different beams for diversity or
throughput gain. [0131] There are at least two UE (RRC) states:
connected state (or called active state) and non-connected state
(or called inactive state or idle state). Inactive state may be an
additional state or belong to connected state or non-connected
state.
[0132] Based on 3GPP R2-162251, to use beamforming in both eNB and
UE sides, practically, antenna gain by beamforming in eNB is
considered about 15 to 30 dBi and the antenna gain of UE is
considered about 3 to 20 dBi. FIG. 20 (quoted from 3GPP R2-162251)
illustrates gain compensation by beamforming.
[0133] From a SINR perspective, sharp beamforming reduces
interference power from neighbor interferers, i.e. neighbor eNBs in
a downlink case or other UEs connected to neighbor eNBs. In a
Transmission (TX) beamforming case, only interference from other
TXs whose current beam points the same direction to the Reception
(RX) will be the "effective" interference. The "effective"
interference means that the interference power is higher than the
effective noise power. In a RX beamforming case, only interference
from other TXs whose beam direction is the same to the UE's current
RX beam direction will be the effective interference. FIG. 21
(quoted from 3GPP R2-162251) illustrates weakened interference by
beamforming.
[0134] As disclosed above, physical layer procedures for
beamforming require multi-beam based approaches. According to one
approach, the eNB performs beamforming to overcome the higher
pathloss in higher frequencies. At one time or at one symbol time,
the eNB generates some of eNB beams instead of all eNB beams due to
the limits of analog or hybrid beamforming. For transmission
scheduling, the eNB requires the beam information of a UE, for
instance, which eNB beam is qualified for the UE.
[0135] According to KT 5G-SIG TS 5G.213 v1.9, KT physical layer
specification specifies three beamforming procedures: Beam
acquisition and tracking, Beam refinement, and Beam Recovery. The
beamforming procedures are utilized for finding a network serving
beam for a UE. The UE shall assume that the downlink transmissions
(e.g., x Physical Downlink Control Channel (xPDCCH), x Physical
Downlink Shared Channel (xPDSCH), Channel State Information
Reference Signal (CSI-RS)) and uplink transmissions (e.g. x
Physical Uplink Control Channel (xPUCCH), x Physical Uplink Shared
Channel (xPUSCH), x Sound Reference Signal (xSRS) are served via
the network serving beam. More specifically, KT physical layer
specification considers only one network serving beam for a UE as
discussed in KT 5G-SIG TS 5G.213 v1.9.
[0136] As specified in KT 5G-SIG TS 5G.213 v1.9, the downlink
transmitting beams are acquired from beam reference signals (BRS).
Up to 8 antenna ports per one symbol are supported for the BRS. A
UE tracks downlink transmitting beams through periodic BRS
measurements. The BRS transmission period is configured by a 2 bit
indicator in x Physical Broadcast Channel (xPBCH). The BRS
transmission period is the necessary time to sweep the whole
downlink network beams transmitted via BRS. There is one BRS
occasion, which comprises multiple symbols, every BRS transmission
period. According to the specification in [8], the BRS transmission
is cell-specific. Fixed downlink transmitting beams are swept every
BRS transmission period for beam acquisition and tracking.
[0137] Beam refinement reference signal (BRRS) are utilized for
beam refinement. BRRS transmission are transmitted on up to eight
antenna ports per one symbol and BRRS can span 1, 2, 5 or 10 OFDM
symbols within one subframe. BRRS is triggered by downlink control
information (DCI) delivered on xPDCCH, and a UE can also request
BRRS using scheduling request preamble. After receiving the DCI
triggering BRRS with BRRS resource allocation and BRRS process
indication, the UE will receive/measure BRRS and report Beam
Refinement Information (BRI), which consists of BRRS Resource Index
(BRRS-RI) and BRRS received power (BRRS-RP), to network. The UE
shall assume that BRRS mapped to the BRRS resource ID 0 in each
BRRS process is transmitted via the network serving beam.
[0138] It may be possible that a UE can have the capability to
perform UE beamforming to get more power gain. When UE beamforming
is applied, the network beam and UE beam should be matched for
successful transmission and reception. The UE should know to
utilize which UE beam(s) for downlink reception and uplink
transmission. The UE beam set, which comprises the UE beam(s) that
are matched to qualified network beam(s), may be obtained via
measuring downlink reference signaling for network beamforming,
e.g. BRS or BRRS. However, if the UE is used with an analog
beamformer or hybrid beamformer, the UE cannot measure or detect
the downlink reference signal via all possible UE beams at the same
time. As a result, it takes much more time for the UE to finish the
downlink reference signaling measurement in order to match the UE
beam and the network beam. For instance, it may take four BRS
transmission periods to finish UE beam sweeping with four UE beams.
Methods to reduce the latency for UE beam sweeping should be
contemplated.
[0139] One potential solution is to shorten the periodicity of the
BRS. In this solution, the beam reference signal transmission
period is shortened from P.sub.BRS to P.sub.BRS/M, in which M may
be the maximum value of the potential UE beam sweeping number. M
may be informed in the system information or may be otherwise
specified. If a UE performs UE beamforming, the UE may perform m
times of UE beam switching to complete network and UE beam
sweeping, wherein 1.ltoreq.m.ltoreq.M. The latency can be kept
shorter than or equal to M P.sub.BRS/M=P.sub.BRS. If the UE
performs UE beam sweeping with m UE beams, the UE can measure each
beam reference signal occasions and requires m
P.sub.BRS/M=P.sub.BRS m/M to finish beam reference signal
measurement with UE beam sweeping. In one embodiment, if the UE
performs UE beam sweeping with m UE beams, the UE may
measure/detect at least m beam reference signal occasions every M
beam reference signal transmission periods. For instance, the UE
can skip the measurement/detection of at most (M-m) beam reference
signal occasions. If the UE is omni-directional without UE
beamforming, the UE can measure/detect one beam reference signal
occasion every M beam reference signal transmission period. The UE
may also skip measurement/detection of at most (M-1) beam reference
signal occasions. The UE, without UE beam sweeping, can finish beam
reference signal measurement with a latency P.sub.BRS.
[0140] Another potential solution is using repetition patterns for
beam sweeping. In this solution, the network node transmits a
downlink reference signal for beam management within one occasion,
and the network node performs network beam sweeping for the
downlink reference signal repeatedly and multiple times according
to a repetition pattern within the occasion. The repetition pattern
is derived/determined via a factor or a number of repetition times.
More specifically, the repetition pattern distributes the symbols
in the occasion into multiple symbol sets. The UE can perform UE
beam sweeping according to the repetition pattern for
measuring/detecting the downlink reference signal. The UE can
switch UE beams for measuring/detecting the downlink reference
signal according to the repetition pattern within the occasion.
[0141] Another potential solution is using repetitions patterns for
beam sweeping using the BRS. For a BRS, the network beam sweeping
repeats M times every BRS transmission period. The BRS is
cell-specific, network node-specific, or TRP-specific. Fixed
downlink transmitting beams are swept every BRS transmission period
for beam acquisition and tracking. The M value may be the maximum
value of possible UE beam sweeping number. The M value may be
informed in system information or specified. As an instance shown
in FIG. 12, the maximum number of beam training opportunities in
one beam reference signal occasion every beam reference signal
transmission period is PN.sub.symb_total.sup.DL, wherein P is the
number of antenna ports per one symbol, N.sub.symb_total.sup.DL is
the number of symbols supportable for beam reference signal
transmission in one beam reference signal occasion. Assuming P=8
and symbol number of one slot N.sub.symb.sup.DL=7, the maximum
number of beam training opportunities every beam reference signal
transmission period is 56/112/224/448 respectively for one slot/one
subframe/two subframes/four subframes supportable for beam
reference signal transmission. The one beam reference signal
occasion may be one slot/one subframe/two subframes/four subframes
(assuming one subframe comprises two slots).
[0142] For assisting UE beam sweeping, a repetition pattern with a
factor M distributes N.sub.symb_total.sup.DL symbols into at least
M symbol sets. The network can perform network beam sweeping at
least one time within each symbol set. Thus, the network beam
sweeping can repeat M times. In one embodiment, each of the M
symbol sets may not have the same number of symbols. In another
embodiment, each of the M symbol sets has the same number of
symbols. The N.sub.symb_total.sup.DL symbols are equally
distributed to at least the M symbol sets. More specifically, each
of the M symbol sets has at least .left
brkt-bot.N.sub.symb_total.sup.DL/M.right brkt-bot. symbols. For
different symbol sets of BRS transmissions, the UE can utilize
different UE beams to measure/detect the beam reference signals.
More specifically, the UE utilizes at least one UE beam to measure
and/or detect the beam reference signals of one symbol set. The UE
can switch to another UE beam(s) to measure and/or detect the beam
reference signals of another symbol set. The repetition pattern
with factor M can support the UE beam sweeping of m UE beams,
wherein 1.ltoreq.m.ltoreq.M.
[0143] When the UE reports a received power and/or quality of a
beam reference signal, the UE may report the symbol index on which
the beam reference signal is measured and/or detected. When UE
reports multiple received power and/or quality of multiple beam
reference signals, the UE may report the symbol indices where the
UE measures and/or detects the multiple beam reference signals. If
the UE performs UE beam sweeping with m UE beams, the UE can at
least measure and/or detect m symbol sets of beam reference signals
in one beam reference signal occasion. More specifically, the UE
can skip the measurement and/or detection of at most (M-m) symbol
sets of beam reference signals in one beam reference signal
occasion. If the UE is omni-directional without UE beamforming, the
UE can measure and/or detect at least one symbol set of beam
reference signals in one beam reference signal occasion. Moreover,
the UE may skip measurement and/or detection of at most (M-1)
symbol sets of the beam reference signals in one beam reference
signal occasion.
[0144] If N.sub.symb_total.sup.DL is not a multiple of M, there are
some remaining symbols in one beam reference signal occasion every
beam reference signal transmission period. For instance, there may
be N.sub.symb_total.sup.DL-M.left
brkt-bot.N.sub.symb_total.sup.DL/M.right brkt-bot. remaining
symbols. As shown in FIG. 23, one beam reference signal occasion
for each beam reference signal transmission period has 14 symbols,
wherein each symbol may include multiple antenna ports for multiple
beam reference signals. The network may generate one network beam
per one antenna port per one symbol. In FIG. 23, the 14 symbols are
distributed into 4 symbol sets, wherein each symbol set includes
three symbols for a beam reference signal transmission. The network
can perform network beam sweeping within each symbol set. Thus, the
network beam sweeping can repeat M times. More specifically, the
network generates the same network beams for beam reference signals
on the 1.sup.st, 4.sup.th, 7.sup.th, and 10.sup.th symbols. The
network generates the same network beams for beam reference signals
on the 2.sup.nd, 5.sup.th, 8.sup.th, and 11.sup.th symbols. The
network generates the same network beams for beam reference signals
on the 3.sup.rd, 6.sup.th, 9.sup.th, and 12.sup.th symbols. For
different symbol sets of beam reference signal transmission, the UE
can utilize different UE beams to measure/detect beam reference
signals.
[0145] Moreover, there are 2 remaining symbols. These remaining
symbol(s) may be utilized for other downlink transmission, e.g.,
CSI-RS. Alternatively, the remaining symbol(s) may be utilized for
other uplink transmission, e.g. SRS. Alternatively, the remaining
symbol(s) may be utilized for beam reference signal transmission
with a longer time (longer than one beam reference signal
transmission period) to sweep the whole network beams of beam
reference signals. The beam reference signal transmission on the
remaining symbol(s) may be utilized for Radio Resource Management
(RRM) measurement. The beam reference signal transmission on the
remaining symbol(s) may be utilized for measurement of other
TRP(s)/network node(s). As shown in FIG. 24, the 1, 2, and 3 means
different network beam sets or different sets of antenna ports for
a beam reference signal. The last two remaining symbols of each
beam reference signal occasion are utilized for the beam reference
signal transmission, and the network cannot finish network beam
sweeping one time with one beam reference signal occasion. The beam
reference signal transmission on the remaining symbol(s) sweeps 2
times every three beam reference signal transmission periods. If
one kind of measurement may require a measurement period longer
than beam reference signal transmission period, the beam reference
signal transmission on the remaining symbol(s) may be utilized for
this kind of measurement.
[0146] Moreover, if synchronization signals are Frequency Division
Multiplexed (FDMed) with a beam reference signal, the network can
perform network beam sweeping for synchronization signals at each
symbol set. Thus, network beam sweeping for synchronization signals
can repeat M times every beam reference signal transmission period.
More specifically, the network beam for beam reference signal may
not be the same as the network beam for synchronization signal at
the same symbol. The antenna port(s) for the beam reference signal
may not be the same as the antenna port(s) for the synchronization
signal at the same symbol. As shown in FIG. 25, the network can
generate the same network beams for the synchronization signals on
the 1.sup.st, 4.sup.th, 7.sup.th, and 10.sup.th symbols. The
network can generate the same network beams for synchronization
signals on the 2.sup.nd, 5.sup.th, 8.sup.th, and 11.sup.th symbols.
The network can generate the same network beams for synchronization
signals on the 3.sup.rd, 6.sup.th, 9.sup.th, and 12.sup.th symbols.
For one kind of synchronization signal, the sequences of the
synchronization signal transmitted on different symbols may be the
same if the synchronization signal transmissions on different
symbols are transmitted on the same antenna port or from the same
network beam. For another kind of synchronization signal, the
sequences/cyclic shifts of the synchronization signal transmitted
on different symbols may be different even if the synchronization
signal transmissions on different symbols are transmitted on the
same antenna port or from the same network beam.
[0147] Moreover, the distributed M symbol sets for beam reference
signal may have the same association with the reception of a
broadcast channel. This means the network beam sweeping for a beam
reference signal/synchronization signal repeats M times, but the
network beam sweeping for a broadcast channel does not repeat, i.e.
sweeping one time. More specifically, for the distributed M symbol
sets, the different M symbols with the same network beam(s) are
associated with the same symbol(s) for the broadcast channel.
Different UEs, which detect beam reference signals on different
symbol sets, may receive the broadcast channel on the same
symbol(s). As shown in FIG. 25, it is assumed that the transmission
timing unit of the broadcast channel transmission is two symbols.
The beam reference signal transmission on the 1.sup.st, 4.sup.th,
7.sup.th, and 10.sup.th symbols are associated with the first two
symbols for broadcast channel transmission. The beam reference
signal transmission on the 2.sup.nd, 5.sup.th, 8.sup.th, and
11.sup.th symbols are associated with the second two symbols for
broadcast channel transmission. The beam reference signal
transmission on the 3.sup.rd, 6.sup.th, 9.sup.th, and 12.sup.th
symbols are associated with the third two symbols for the broadcast
channel transmission.
[0148] Moreover, the distributed M symbol sets for the beam
reference signal may have the same association with the uplink
transmission of the preamble. It means that the network beam
sweeping for the beam reference signal/synchronization signal
repeats M times, but the network beam sweeping for receiving the
preamble does not repeat, i.e. sweeping one time. More
specifically, for the distributed M symbol sets, the different M
symbols with the same network beam(s) are associated with the same
symbol(s) for the preamble. Different UEs, which detect beam
reference signals on different symbol sets, may transmit the
preamble on the same symbol(s). As shown in FIG. 26, it is assumed
that the transmission timing unit of the preamble transmission is
two symbols. The beam reference signal transmission on the
1.sup.st, 4.sup.th, 7.sup.th, and 10.sup.th symbols are associated
with the first two symbols for the preamble reception. The beam
reference signal transmission on the 2.sup.nd, 5.sup.th, 8.sup.th,
and 11.sup.th symbols are associated with the second two symbols
for the preamble reception. The beam reference signal transmission
on the 3.sup.rd, 6.sup.th, 9.sup.th, and 12.sup.th symbols are
associated with the third two symbols for the preamble reception.
The preamble may be used for random access. Alternately, the
preamble may be for beam recovery. The preamble may be for a
request of an aperiodic reference signal. More specifically, the
preamble is a scheduling request preamble.
[0149] Another potential solution is using repetitions patterns for
beam sweeping using beam refinement reference signal. If the
network triggers a downlink beam refinement reference signal for
the UE to measure and/or detect, the network may perform network
beam sweeping N times within the triggered measurement occasion.
The triggered measurement occasion may be composed of
N.sub.symb_trigger.sup.DL symbols. More specifically,
N.sub.symb_trigger.sup.DL may be indicated in the downlink
signaling for the triggering downlink beam refinement reference
signal for UE measurement/detection. N.sub.symb_trigger.sup.DL may
be 5 or 10. A repetition pattern(s) with a factor N is to
distribute N.sub.symb_trigger.sup.DL symbols into at least N symbol
sets. The repetition pattern(s) can be configured or specified. The
value N may be configured or indicated in the downlink signaling.
The value Nis smaller than or equal to M, wherein M may be the
maximum value of possible UE beam sweeping numbers. M may be
informed in the system information or may be specified.
Alternatively, the UE may report the maximum value of N to the
network as an UE capability or UE suggestion. In one embodiment,
the N.sub.symb_trigger.sup.DL symbols are equally distributed to at
least N symbol sets. Alternatively, the N.sub.symb_trigger.sup.DL
symbols are not equally distributed to the N symbol sets. More
specifically, each of the N symbol sets is composed of at least
.left brkt-bot.N.sub.symb_trigger.sup.DL/N.right brkt-bot. symbols.
If N.sub.symb_trigger.sup.DL is not multiple times of N, (N-1)
symbol sets may be composed of the same number of symbols, and one
symbol set is composed of the remaining symbols. In another
embodiment, (N-1) symbol sets are composed of at least .left
brkt-bot.N.sub.symb_trigger.sup.DL/N.right brkt-bot. symbols, and
one symbol set is composed of N.sub.symb_trigger.sup.DL-(N-1).left
brkt-bot.N.sub.symb_trigger.sup.DL/N.right brkt-bot. remaining
symbols. In another embodiment, (N-1) symbol sets are composed of
at least .left brkt-bot.N.sub.symb_trigger.sup.DL/(N-1).right
brkt-bot. symbols and one symbol set is composed of
N.sub.symb_trigger.sup.DL-(N-1).left
brkt-bot.N.sub.symb_trigger.sup.DL/(N-1).right brkt-bot. remaining
symbols.
[0150] For different symbol sets of downlink beam refinement
reference signal, the UE can utilize different UE beams to
measure/detect the downlink beam refinement reference signal
transmission. More specifically, the UE utilizes at least one UE
beam to measure/detect the downlink beam refinement reference
signal transmissions of one symbol set. The UE can switch to
another UE beam to measure/detect the downlink beam refinement
reference signal transmissions of another symbol set. The
repetition pattern with the factor N can support the UE beam
sweeping of n UE beams, wherein 1.ltoreq.n.ltoreq.N. The downlink
signaling may indicate which UE beam(s) are utilized to
measure/detect the triggered downlink beam refinement reference
signals. When the UE reports a received power/quality of a downlink
beam refinement reference signal, the UE may report the symbol
index on which the downlink beam refinement reference signal is
measured/detected. When the UE reports that it has received
multiple power/quality values from multiple downlink beam
refinement reference signals, the UE may report the symbol indices
where the UE measures/detects the multiple downlink beam refinement
reference signals.
[0151] The UE may use the UE serving beam to measure/detect the one
symbol set which is composed of the remaining symbols.
Alternatively, the UE may use the UE serving beam to measure/detect
the first one symbol set within the triggered measurement occasion.
If the downlink signaling indicates N=1, the UE may use the UE
serving beam to measure/detect the triggered downlink beam
refinement reference signal. Alternatively, the downlink signaling
may indicate which UE beam is utilized for measuring/detecting the
triggered downlink beam refinement reference signals. The indicated
UE beam for measurement/detection may not be the UE serving beam.
More specifically, N=1 may mean that the network performs the
network beam sweeping one time within the triggered measurement
occasion. In one embodiment, N.sub.symb_trigger.sup.DL trigger may
be 1 or 2. More specifically, if N=1, N.sub.symb_trigger.sup.DL may
be 1 or 2.
[0152] As shown in FIG. 27, one triggered measurement occasion is
composed of 10 symbols, which is distributed into 4 symbol sets for
downlink beam refinement reference signal. The UE may utilize the
UE serving beam for measuring/detecting a downlink beam refinement
reference signal on the first symbol set. For other three symbol
sets, the network can perform network beam sweeping at each symbol
set. More specifically, the network generates the same network
beams for the downlink beam refinement reference signals on the
2nd, 5th, and 8th symbols. The network generates the same network
beams for the downlink beam refinement reference signals on the
3rd, 6th, and 9th symbols. The network generates the same network
beams for the downlink beam reference signals on the 4th, 7th, and
10th symbols. For different symbol sets of the downlink beam
refinement reference signal, the UE can utilize different UE beams
to measure/detect the downlink beam refinement reference signal
transmission. For instance, as shown in FIG. 27, a UE can be
supported with four UE beams sweeping.
[0153] Generally, according to KT 5G-SIG TS 5G.213 v1.9, a UE
tracks downlink transmitting beams through the periodic beam
reference signal measurements. The beam reference signal
transmission period is configured by a 2 bit indicator in xPBCH.
Therefore, the beam reference signal transmission period is common
for all UEs in a cell.
[0154] In case where UEs are moving across a cell, a UE with a
higher speed will need to track the downlink transmitting beams
more frequently than a UE with a lower speed. Thus, the common beam
reference signal transmission period should be small enough to cope
with the highest speed UE. In this situation, the low speed UEs
will perform beam reference signal measurements more frequently
than needed, which will consume UE power unnecessarily.
[0155] It is beneficial for UEs to perform beam reference signal
measurements with different periods according to their own needs.
For example, a UE may measure beam reference signal with a first
periodicity, which is greater than a second periodicity broadcast
in the system information. The first periodicity may be determined
by the UE itself or configured by a network node. The determination
may be made according to UE speed or a variation of the serving
beam quality (e.g., if the serving beam quality maintains at high
quality for certain time, the UE may lower the first periodicity;
otherwise, the first periodicity is increased).
[0156] As those skilled in the art will appreciate, the network
beam(s) mentioned above may be beamformed from a network node or a
TRP. Moreover, the network beam(s) mentioned above may be
beamformed from multiple network nodes or multiple TRPs.
[0157] FIG. 28 is a flow chart 2800 according to one exemplary
embodiment from the perspective of a network. In step 2805, the
network node transmits a reference signal for beam management
within one occasion, wherein the occasion comprises at least M
symbol sets. In step 2810, the network node performs beam sweeping
for transmitting the reference signal in a first symbol set of the
M symbol sets. In step 2815, the network node repeats the beam
sweeping for transmitting the reference signal in the rest of the M
symbol sets.
[0158] In one embodiment, the beam sweeping means the network node
generates at least one beam for transmission in a first symbol of a
symbol set and then switches beam(s) for transmission in a second
symbol of the symbol set, and so on until the last symbol of the
symbol set.
[0159] In one embodiment, M is number of repetition times.
[0160] In one embodiment, the network node receives a report
including a received power or quality of the reference signal from
a UE. Preferably, the report includes an index associated with a
symbol in which the reported received power or the reported quality
of the reference signal is measured.
[0161] In one embodiment, the number of symbols in the different
symbol sets are the same.
[0162] In one embodiment, the reference signal is a periodic
reference signal, wherein there is at least one occasion of the
reference signal every transmission period.
[0163] In one embodiment, the reference signal is an aperiodic
reference signal triggered by the network node for UE measurement
or UE detection.
[0164] FIG. 29 is a flow chart 2900 according to one exemplary
embodiment from the perspective of a UE. In step 2905, the UE
measures a reference signal for beam management within one
occasion, wherein the occasion comprises at least M symbol sets. In
step 2910, the UE switches UE beams for measuring the reference
signal within the occasion.
[0165] In one embodiment, there are multiple symbols in each symbol
set.
[0166] In one embodiment, M is equal to a UE beam sweeping number
of the UE.
[0167] In one embodiment, the UE performs UE beam switching m
times, in which 1.ltoreq.m.ltoreq.M.
[0168] In one embodiment, the UE utilizes at least one UE beam to
measure the reference signals of a first symbol set of the M symbol
sets, and the UE switches to another UE beam to measure the
reference signals of a second symbol set of the M symbol sets.
[0169] In one embodiment, the number of symbols in the different
symbol sets are the same.
[0170] In one embodiment, the reference signal is a periodic
reference signal, wherein there is at least one occasion of the
reference signal every transmission period.
[0171] In one embodiment, the reference signal is triggered via a
downlink signaling wherein the one occasion of the reference signal
is indicated in the downlink signaling.
[0172] In one embodiment, the UE reports a received power or
quality of the reference signal, and an index associated with a
symbol in which the reported received power or the reported quality
of the reference signal is measured.
[0173] In one or more of the above-disclosed methods, the
repetition pattern is derived/determined via a factor or number of
repetition times.
[0174] In one or more of the above-disclosed methods, the
repetition pattern is to distribute the symbols in the occasion
into multiple symbol sets.
[0175] In one or more of the above-disclosed methods, the reference
signal is periodic reference signal.
[0176] In one or more of the above-disclosed methods, there is at
least one occasion of the reference signal every transmission
period of the downlink reference signal.
[0177] In one or more of the above-disclosed methods, the reference
signal is cell-specific, network-node specific, TRP-specific, or
TRP-specific.
[0178] In one or more of the above-disclosed methods, the reference
signal is beam reference signal.
[0179] In one or more of the above-disclosed methods, the fixed
downlink transmitting beams are swept every the transmission period
of the reference signal.
[0180] In one or more of the above-disclosed methods, the network
beam sweeping repeats M times in the occasion.
[0181] In one or more of the above-disclosed methods, M is the
maximum value of possible UE beam sweeping number.
[0182] In one or more of the above-disclosed methods, M is informed
in system information or specified.
[0183] In one or more of the above-disclosed methods, the
repetition pattern is to distribute the symbols in the occasion
into at least M symbol sets.
[0184] In one or more of the above-disclosed methods, the
repetition pattern is configured or specified.
[0185] In one or more of the above-disclosed methods, the network
node performs the network beam sweeping at least one time within
each symbol set.
[0186] In one or more of the above-disclosed methods, each of the M
symbol sets does not comprise the same number of symbols.
Alternatively, each of the M symbol sets comprises the same number
of symbols.
[0187] In one or more of the above-disclosed methods,
N.sub.symb_total.sup.DL is the number of symbols in the
occasion.
[0188] In one or more of the above-disclosed methods, the
N.sub.symb_total.sup.DL symbols are equally distributed to the at
least M symbol sets.
[0189] In one or more of the above-disclosed methods, each of the M
symbol sets comprises at least .left
brkt-bot.N.sub.symb_total.sup.DL/M.right brkt-bot. symbols
[0190] In one or more of the above-disclosed methods, the UE
utilizes different UE beams to measure/detect the reference signal
for different symbol sets of the reference signal.
[0191] In one or more of the above-disclosed methods, the UE
utilizes at least one UE beam to measure/detect the reference
signals of one symbol set. The UE then switches to another UE beam
to measure/detect the reference signals of another symbol set.
[0192] In one or more of the above-disclosed methods, when the UE
reports a received power/quality of a reference signal for beam
management, the UE reports the symbol index on which the reference
signal is measured/detected.
[0193] In one or more of the above-disclosed methods, when the UE
reports multiple received power/quality from multiple reference
signals for beam management, the UE reports the symbol indices
where the UE measures/detects the multiple reference signals.
[0194] In one or more of the above-disclosed methods, if the UE
performs UE beam sweeping with m UE beams, the UE measures/detects
at least m symbol sets of the reference signals in the one
occasion. Alternatively, if the UE performs UE beam sweeping with m
UE beams, the UE skips measurement/detection of at most (M-m)
symbol sets of the reference signals in the one occasion.
[0195] In one or more of the above-disclosed methods, if the UE is
omni-directional without UE beamforming, the UE measures/detects at
least one symbol set of the reference signals in the one occasion.
Alternatively, if the UE is omni-directional without UE
beamforming, the UE skips measurement/detection of at most (M-1)
symbol sets of the reference signals in the one occasion.
[0196] In one or more of the above-disclosed methods, a symbol in
the occasion comprises multiple antenna ports for multiple the
reference signals.
[0197] In one or more of the above-disclosed methods, the network
node may generate one network beam per one antenna port per one
symbol.
[0198] In one or more of the above-disclosed methods, if
N.sub.symb_total.sup.DL is not multiple times of M, there are some
remaining symbols in the one occasion every the transmission period
of the reference signal. Alternatively, if N.sub.symb_total.sup.DL
is not multiple times of M, there are
N.sub.symb_total.sup.DL-M.left
brkt-bot.N.sub.symb_total.sup.DL/M.right brkt-bot. remaining
symbols in the one occasion every the transmission period of the
reference signal.
[0199] In one or more of the above-disclosed methods, the remaining
symbol(s) are utilized for CSI-RS transmission. Alternatively, the
remaining symbol(s) are utilized for SRS transmission. n another
alternative, the remaining symbol(s) are utilized for the reference
signal transmission with the longer time (i.e., a time longer than
one transmission period of the reference signal) to sweep the whole
network's reference signal beams.
[0200] In one or more of the above-disclosed methods, the reference
signal transmissions on the remaining symbol(s) are utilized for
RRM measurement. Alternatively, the reference signal transmissions
on the remaining symbol(s) are utilized for the measurement of
other TRP(s)/network node(s). In another alternative, the reference
signal transmissions on the remaining symbol(s) are utilized for
one kind of measurement with the requirement that the measurement
period is longer than the transmission period of the reference
signal.
[0201] In one or more of the above-disclosed methods, the
synchronization signals are FDMed with beam reference signal.
[0202] In one or more of the above-disclosed methods, the network
beams for the beam reference signal are not the same as the network
beams for the synchronization signal at the same symbol.
[0203] In one or more of the above-disclosed methods, the antenna
ports for the beam reference signal are not the same as the antenna
ports for the synchronization signal at the same symbol.
[0204] In one or more of the above-disclosed methods, the network
node performs network beam sweeping for the synchronization signals
at each symbol set.
[0205] In one or more of the above-disclosed methods, the network
beam sweeping for the synchronization signals repeats M times every
transmission period of the reference signal.
[0206] In one or more of the above-disclosed methods, the sequences
of the synchronization signal transmitted on different symbols are
the same if the synchronization signal transmissions on the
different symbols are transmitted on the same antenna port or from
the same network beam. Alternatively, the sequences/cyclic shifts
of the synchronization signal transmitted on different symbols are
different even if the synchronization signal transmissions on the
different symbols are transmitted on the same antenna port or from
the same network beam.
[0207] In one or more of the above-disclosed methods, the
distributed multiple symbol sets for the reference signal may have
the same association with the broadcast channel.
[0208] In one or more of the above-disclosed methods, the network
beam sweeping for the reference signal/synchronization signal
repeats multiple times, but the network beam sweeping for the
broadcast channel does not repeat, i.e., sweeps one time.
[0209] In one or more of the above-disclosed methods, for the
distributed M symbol sets, the different M symbols with the same
network beam(s) are associated with the same symbol(s) for
broadcast channel.
[0210] In one or more of the above-disclosed methods, different
UEs, which detect the reference signals on different symbol sets,
may receive broadcast channel on the same symbol(s).
[0211] In one or more of the above-disclosed methods, the
distributed multiple symbol sets for the reference signal have the
same association with the uplink transmission of the preamble.
[0212] In one or more of the above-disclosed methods, the network
beam sweeping for the reference signal/synchronization signal
repeats multiple times, but the network beam sweeping for receiving
the preamble does not repeat, i.e., sweeps one time.
[0213] In one or more of the above-disclosed methods, for the
distributed M symbol sets, the different M symbols with the same
network beam(s) are associated with the same symbol(s) for the
preamble.
[0214] In one or more of the above-disclosed methods, different
UEs, which detect the reference signals on different symbol sets,
may transmit the preamble on the same symbol(s).
[0215] In one or more of the above-disclosed methods, the occasion
may be one slot, one subframe, two subframes, or four
subframes.
[0216] In one or more of the above-disclosed methods, the preamble
may be for random access, beam recovery, the request of aperiodic
reference signal, or a scheduling preamble.
[0217] In one or more of the above-disclosed methods, the reference
signal is triggered by the network node for the UE to
measure/detect. Alternatively, the reference signal is triggered by
downlink signaling.
[0218] In one or more of the above-disclosed methods, the reference
signal is an aperiodic reference signal. In another alternative,
the reference signal is a beam refinement reference signal.
[0219] In one or more of the above-disclosed methods, the occasion
for the reference signal is indicated in the downlink signaling for
triggering the reference signal.
[0220] In one or more of the above-disclosed methods, the triggered
occasion for the reference signal comprises 5 or 10 symbols.
[0221] In one or more of the above-disclosed methods, the network
performs the network beam sweeping N times within the triggered
occasion.
[0222] In one or more of the above-disclosed methods,
N.sub.symb_trigger.sup.DL is the number of symbols in the triggered
occasion.
[0223] In one or more of the above-disclosed methods, the
repetition pattern is to distribute the N.sub.symb_trigger.sup.DL
symbols in the triggered occasion into at least N symbol sets.
[0224] In one or more of the above-disclosed methods, the
repetition pattern is configured or specified.
[0225] In one or more of the above-disclosed methods, N is
configured or indicated in the downlink signaling.
[0226] In one or more of the above-disclosed methods, the UE
reports the maximum value of N to the network as a UE capability or
a UE suggestion.
[0227] In one or more of the above-disclosed methods, the
N.sub.symb_trigger.sup.DL symbols are equally distributed to the at
least N symbol sets. Alternatively, the N.sub.symb_trigger.sup.DL
symbols are not equally distributed to the at least N symbol
sets.
[0228] In one or more of the above-disclosed methods, each of the N
symbol sets has at least .left
brkt-bot.N.sub.symb_trigger.sup.DL/N.right brkt-bot. symbols
[0229] In one or more of the above-disclosed methods, if
N.sub.symb_trigger.sup.DL is not multiple times of N, (N-1) symbol
sets has the same number of symbols and one symbol set includes the
remaining symbols.
[0230] In one or more of the above-disclosed methods, if
N.sub.symb_trigger.sup.DL is not multiple times of N, (N-1) symbol
sets has at least .left brkt-bot.N.sub.symb_trigger.sup.DL/N.right
brkt-bot. symbols and one symbol set has
N.sub.symb_trigger.sup.DL-(N-1).left
brkt-bot.N.sub.symb_trigger.sup.DL/N.right brkt-bot. remaining
symbols.
[0231] In one or more of the above-disclosed methods, if
N.sub.symb_trigger.sup.DL is not multiple times of N, (N-1) symbol
sets has at least .left
brkt-bot.N.sub.symb_trigger.sup.DL/(N-1).right brkt-bot. symbols
and one symbol set has N.sub.symb_trigger.sup.DL-(N-1).left
brkt-bot.N.sub.symb_trigger.sup.DL/(N-1).right brkt-bot. remaining
symbols.
[0232] In one or more of the above-disclosed methods, for different
symbol sets of the reference signal, the UE utilizes different UE
beams to measure/detect the triggered reference signal.
[0233] In one or more of the above-disclosed methods, the UE
utilizes at least one UE beam to measure/detect the triggered
reference signals of one symbol set. The UE then switches to
another UE beam to measure/detect the triggered reference signals
of another symbol set.
[0234] In one or more of the above-disclosed methods, when UE
reports a received power/quality of the trigger reference signal
for beam management, the UE reports the symbol index on which the
reference signal is measured/detected. Alternatively, when UE
reports multiple received power/quality of the triggered multiple
reference signals for beam management, the UE reports the symbol
indices where the UE measures/detects the multiple reference
signals.
[0235] In one or more of the above-disclosed methods, the UE uses
the UE serving beam for measuring/detecting the one symbol set that
has the remaining symbols.
[0236] In one or more of the above-disclosed methods, the UE uses
the UE serving beam for measuring/detecting the first one symbol
set within the triggered occasion.
[0237] In one or more of the above-disclosed methods, if the
downlink signaling indicates N=1, the UE uses the UE serving beam
for measuring/detecting the triggered reference signal.
[0238] In one or more of the above-disclosed methods, the downlink
signaling indicates which UE beam(s) are utilized for
measuring/detecting the triggered reference signals.
[0239] In one or more of the above-disclosed methods, the indicated
UE beam(s) for measuring/detecting the triggered reference signals
may not be the UE serving beam.
[0240] In one or more of the above-disclosed methods, N=1 means
that the network performs the network beam sweeping one time within
the triggered occasion.
[0241] In one or more of the above-disclosed methods, the triggered
occasion for the reference signal has 1 or 2 symbols.
[0242] In one or more of the above-disclosed methods, if N=1, the
triggered occasion for the reference signal has 1 or 2 symbols.
[0243] According to another exemplary method, the UE
measures/detects reference signals for beam management with a first
periodicity. The reference signals are periodically transmitted
with a second periodicity, wherein the first periodicity is greater
than the second periodicity.
[0244] In another exemplary method, the reference signal is a beam
reference signal.
[0245] In another exemplary method, the second periodicity is
broadcast in the system information.
[0246] In another exemplary method, the UE adjusts/determines the
first periodicity according to the UE speed.
[0247] In another exemplary method, the UE adjusts/determines the
first periodicity according to the variation of the serving beam
quality.
[0248] In another exemplary method, if the serving beam quality
maintains a high quality for certain time period, the UE may lower
the first periodicity; otherwise, the first periodicity is
increased.
[0249] Referring back to FIGS. 3 and 4, in one embodiment, the
device 300 includes a program code 312 stored in memory 310. The
CPU 308 could execute program code 312 (i) to enable the network to
transmit a reference signal for beam management within one
occasion, wherein the occasion comprises at least M symbol sets,
(ii) to perform beam sweeping for transmitting the reference signal
in a first symbol set of the M symbol sets, and (iii) to repeat the
beam sweeping for transmitting the reference signal in the rest of
the M symbol sets.
[0250] In another aspect, the CPU 308 could execute program code
312 to (i) enable the UE to measure a reference signal for beam
management within one occasion, wherein the occasion comprises at
least M symbol sets, and (ii) and to switch UE beams for measuring
the reference signal within the occasion.
[0251] Furthermore, the CPU 308 can execute the program code 312 to
perform all of the above-described actions and steps or others
methods described herein.
[0252] Various aspects of the disclosure have been described above.
It should be apparent that the teachings herein may be embodied in
a wide variety of forms and that any specific structure, function,
or both being disclosed herein is merely representative. Based on
the teachings herein one skilled in the art should appreciate that
an aspect disclosed herein may be implemented independently of any
other aspects and that two or more of these aspects may be combined
in various ways. For example, an apparatus may be implemented or a
method may be practiced using any number of the aspects set forth
herein. In addition, such an apparatus may be implemented or such a
method may be practiced using other structure, functionality, or
structure and functionality in addition to or other than one or
more of the aspects set forth herein. As an example of some of the
above concepts, in some aspects concurrent channels may be
established based on pulse repetition frequencies. In some aspects
concurrent channels may be established based on pulse position or
offsets. In some aspects concurrent channels may be established
based on time hopping sequences.
[0253] Those of skill in the art would understand that information
and signals may be represented using any of a variety of different
technologies and techniques. For example, data, instructions,
commands, information, signals, bits, symbols, and chips that may
be referenced throughout the above description may be represented
by voltages, currents, electromagnetic waves, magnetic fields or
particles, optical fields or particles, or any combination
thereof.
[0254] Those of skill would further appreciate that the various
illustrative logical blocks, modules, processors, means, circuits,
and algorithm steps described in connection with the aspects
disclosed herein may be implemented as electronic hardware (e.g., a
digital implementation, an analog implementation, or a combination
of the two, which may be designed using source coding or some other
technique), various forms of program or design code incorporating
instructions (which may be referred to herein, for convenience, as
"software" or a "software module"), or combinations of both. To
clearly illustrate this interchangeability of hardware and
software, various illustrative components, blocks, modules,
circuits, and steps have been described above generally in terms of
their functionality. Whether such functionality is implemented as
hardware or software depends upon the particular application and
design constraints imposed on the overall system. Skilled artisans
may implement the described functionality in varying ways for each
particular application, but such implementation decisions should
not be interpreted as causing a departure from the scope of the
present disclosure.
[0255] In addition, the various illustrative logical blocks,
modules, and circuits described in connection with the aspects
disclosed herein may be implemented within or performed by an
integrated circuit ("IC"), an access terminal, or an access point.
The IC may comprise a general purpose processor, a digital signal
processor (DSP), an application specific integrated circuit (ASIC),
a field programmable gate array (FPGA) or other programmable logic
device, discrete gate or transistor logic, discrete hardware
components, electrical components, optical components, mechanical
components, or any combination thereof designed to perform the
functions described herein, and may execute codes or instructions
that reside within the IC, outside of the IC, or both. A general
purpose processor may be a microprocessor, but in the alternative,
the processor may be any conventional processor, controller,
microcontroller, or state machine. A processor may also be
implemented as a combination of computing devices, e.g., a
combination of a DSP and a microprocessor, a plurality of
microprocessors, one or more microprocessors in conjunction with a
DSP core, or any other such configuration.
[0256] It is understood that any specific order or hierarchy of
steps in any disclosed process is an example of a sample approach.
Based upon design preferences, it is understood that the specific
order or hierarchy of steps in the processes may be rearranged
while remaining within the scope of the present disclosure. The
accompanying method claims present elements of the various steps in
a sample order, and are not meant to be limited to the specific
order or hierarchy presented.
[0257] The steps of a method or algorithm described in connection
with the aspects disclosed herein may be embodied directly in
hardware, in a software module executed by a processor, or in a
combination of the two. A software module (e.g., including
executable instructions and related data) and other data may reside
in a data memory such as RAM memory, flash memory, ROM memory,
EPROM memory, EEPROM memory, registers, a hard disk, a removable
disk, a CD-ROM, or any other form of computer-readable storage
medium known in the art. A sample storage medium may be coupled to
a machine such as, for example, a computer/processor (which may be
referred to herein, for convenience, as a "processor") such the
processor can read information (e.g., code) from and write
information to the storage medium. A sample storage medium may be
integral to the processor. The processor and the storage medium may
reside in an ASIC. The ASIC may reside in user equipment. In the
alternative, the processor and the storage medium may reside as
discrete components in user equipment. Moreover, in some aspects
any suitable computer-program product may comprise a
computer-readable medium comprising codes relating to one or more
of the aspects of the disclosure. In some aspects a computer
program product may comprise packaging materials.
[0258] While the invention has been described in connection with
various aspects, it will be understood that the invention is
capable of further modifications. This application is intended to
cover any variations, uses or adaptation of the invention
following, in general, the principles of the invention, and
including such departures from the present disclosure as come
within the known and customary practice within the art to which the
invention pertains.
* * * * *