U.S. patent application number 16/489087 was filed with the patent office on 2020-01-02 for management of mimo communication systems.
This patent application is currently assigned to INTEL CORPORATION. The applicant listed for this patent is INTEL CORPORATION. Invention is credited to Mustafa Akdeniz, Ehsan Aryafar, Nageen Himayat, Wook Bong Lee, Hosein Nikopour, Oner Orhan, Jan Schreck, Feng Xue, Jing Zhu.
Application Number | 20200007200 16/489087 |
Document ID | / |
Family ID | 62200547 |
Filed Date | 2020-01-02 |
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United States Patent
Application |
20200007200 |
Kind Code |
A1 |
Schreck; Jan ; et
al. |
January 2, 2020 |
MANAGEMENT OF MIMO COMMUNICATION SYSTEMS
Abstract
Apparatuses of a user equipment (UE), a cellular base station,
and radio access network (RAN) nodes are disclosed. An apparatus of
a wireless communication device includes circuitry configured to
measure reference signals received from a plurality of antennas of
an other wireless communication device, and circuitry configured to
cause one or more antennas of the wireless communication device to
transmit information regarding the received reference signals back
to the other wireless communication device to enable the other
wireless communication device to estimate a utility function for
different transmit parameter sets.
Inventors: |
Schreck; Jan; (Sunnyvale,
CA) ; Himayat; Nageen; (Fremont, CA) ;
Nikopour; Hosein; (San Jose, CA) ; Xue; Feng;
(Redwood City, CA) ; Aryafar; Ehsan; (Santa Clara,
CA) ; Orhan; Oner; (San Jose, CA) ; Akdeniz;
Mustafa; (San Jose, CA) ; Lee; Wook Bong;
(Pleasanton, CA) ; Zhu; Jing; (Portland,
OR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
INTEL CORPORATION |
Santa Clara |
CA |
US |
|
|
Assignee: |
INTEL CORPORATION
Santa Clara
CA
|
Family ID: |
62200547 |
Appl. No.: |
16/489087 |
Filed: |
April 30, 2018 |
PCT Filed: |
April 30, 2018 |
PCT NO: |
PCT/US2018/030250 |
371 Date: |
August 27, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62502036 |
May 5, 2017 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 5/0051 20130101;
H04B 7/0617 20130101; H04B 7/0626 20130101; H04W 72/1231 20130101;
H04W 72/1226 20130101; H04B 7/0456 20130101; H04B 7/0417
20130101 |
International
Class: |
H04B 7/0456 20060101
H04B007/0456; H04B 7/06 20060101 H04B007/06; H04B 7/0417 20060101
H04B007/0417; H04L 5/00 20060101 H04L005/00; H04W 72/12 20060101
H04W072/12 |
Claims
1. An apparatus of a wireless communication device, comprising:
circuitry configured to measure reference signals received from a
plurality of antennas of an other wireless communication device;
and circuitry configured to cause one or more antennas of the
wireless communication device to transmit information regarding the
received reference signals back to the other wireless communication
device to enable the other wireless communication device to
estimate a utility function for different transmit parameter
sets.
2. The apparatus of claim 1, wherein the circuitry configured to
cause the one or more antennas of the wireless communication device
to transmit the information regarding the received reference
signals is further configured to perform some pre-processing of the
reference signals to reduce processing at the other wireless
communication device to estimate the utility function.
3. The apparatus of claim 1, wherein the circuitry configured to
cause the one or more antennas of the wireless communication device
to transmit the information regarding the received reference
signals is further configured to quantize the reference signals,
and the information regarding the received reference signals
comprises data indicating the quantized reference signals.
4. The apparatus of claim 1, wherein the one or more antennas of
the wireless communication device comprise multiple antennas and
the circuitry configured to cause the one or more antennas of the
wireless communication device to transmit the information regarding
the received reference signals is further configured to fix a
receive beamforming vector before the reference signals are
received.
5. The apparatus of claim 1, wherein the information regarding the
received reference signals comprises the reference signals
themselves that have not been quantized by the circuitry configured
to cause the one or more antennas of the wireless communication
device to transmit the information regarding the received reference
signals.
6. The apparatus of claim 1, wherein the circuitry configured to
cause the one or more antennas of the wireless communication device
to transmit the information regarding the received reference
signals is further configured to generate other reference signals
and control the the one or more antennas to transmit the other
reference signals to the other wireless communication device to
enable the other wireless communication device to measure the
uplink channel.
7. The apparatus of claim 1, wherein the circuitry configured to
cause the one or more antennas of the wireless communication device
to transmit the information regarding the received reference
signals is further configured to determine whether a codebook used
to generate the reference signals at the other wireless
communication device should be updated, and control the radio
frequency circuitry and the one or more antennas to indicate to the
other wireless communication device that the codebook should be
updated.
8. The apparatus of claim 1, wherein the wireless communication
device includes a user equipment (UE) and the other wireless
communication device includes a cellular base station.
9. The apparatus of claim 1, wherein the circuitry configured to
measure the reference signals received from the plurality of
antennas of the other wireless communication device comprises radio
frequency circuitry.
10. The apparatus of claim 1, wherein the circuitry configured to
cause the one or more antennas of the wireless communication device
to transmit the information regarding the received reference
signals back to the other wireless communication device comprises
processing circuitry.
11. An apparatus of a cellular base station, comprising: a data
storage device configured to store data corresponding to a first
codebook and a second codebook, the first codebook different from
the second codebook; and one or more processors configured to:
precode reference signals to be transmitted to a user equipment
(UE); and precode, using the second codebook, data streams on a
common resource element to prevent the data streams from
interfering with each other.
12. The apparatus of claim 11, wherein one or more of the first
codebook or the second codebook is updated or replaced with a
different codebook responsive to: a determination that a wireless
propagation environment between the cellular base station and the
UE has changed; or an indication by the UE that the wireless
propagation environment has changed.
13. An apparatus of a Radio Access Network (RAN) node, comprising:
a data storage device configured to store data corresponding to
feedback information received from a UE; and processing circuitry
configured to: estimate a utility function for different transmit
parameter sets based on the feedback information received from the
UE; and generate reference signals to be transmitted to the UE, the
feedback information indicating information regarding measured
signals measured by the UE responsive to transmission of the
reference signals to the UE.
14. The apparatus of claim 13, wherein the processing circuitry is
configured to use a first codebook to precode the reference signals
and a second codebook to precode data streams to be transmitted to
the UE.
15. The apparatus of claim 14, wherein the first codebook is the
same as the second codebook.
16. The apparatus of claim 13, wherein the processing circuitry is
configured to optimize the estimated utility function for the
different transmit parameter sets.
17. The apparatus of claim 13, wherein the processing circuitry is
configured to take into consideration statistical information about
a wireless channel to estimate the utility function.
18. An apparatus of a user equipment (UE), comprising: a data
storage device configured to store a first beamforming codebook and
a second beamforming codebook that is different from the first
beamforming codebook; and processing circuitry configured to: use
the first beamforming codebook to reduce or compress dimensions of
a receive beam space of a plurality of antennas of the UE; and use
the second beamforming codebook to filter data bearing signals
received from a cellular base station.
19. The apparatus of claim 18, wherein the processing circuitry is
configured to transition to use a third beamforming codebook
instead of one or more of the first beamforming codebook or the
second beamforming codebook responsive to a change in a signal
propagation environment.
20. The apparatus of claim 18, wherein the one or more processors
are configured to generate a message to be transmitted to a
cellular base station, the message configured to indicate a number
of reference signals that are to be transmitted by the cellular
base station.
21. The apparatus of claim 20, wherein the processing circuitry is
configured to generate the message to be transmitted to multiple
cellular base stations.
22. The apparatus of claim 18, wherein the processing circuitry is
configured to: estimate an effective channel gain for one or more
beam pairs; and generate a message to be transmitted to a cellular
base station, the message indicating the estimated effective
channel gain.
23. The apparatus of claim 18, wherein the processing circuitry is
configured to determine an optimal receive beam from the second
beamforming codebook based on measurements of reference signals
received from a cellular base station while using the first
beamforming codebook.
24. An apparatus of a user equipment (UE), comprising: a data
storage device configured to store sample data indicating
information measured from a uniformly sampled receive beam space;
and one or more processors configured to: estimate one or more
parameters of a plurality of receive beams of a codebook based on
the stored samples; select a receive beam from a codebook based on
the estimated one or more parameters; and receive data from a
cellular base station using the selected receive beam.
25. The apparatus of claim 24, wherein the one or more processors
are configured to generate an acknowledgement (ACK) message to be
transmitted to the cellular base station, the ACK message
indicating that a quality of samples of the uniformly sampled
receive beam space is sufficient.
26. The apparatus of claim 24, wherein the one or more processors
are configured to classify some of the samples of the uniformly
sampled receive beam space as useful and others of the samples of
the uniformly sampled receive beam space as not useful.
27. The apparatus of claim 24, wherein the one or more parameters
used to select the receive beam from the codebook are determined by
defining a function that depends on the sample data and a potential
receive beam, the function chosen to approximate an effective
channel gain.
Description
RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent
Application No. 62/502,036, filed May 5, 2017, the entire
disclosure of which is hereby incorporated herein by reference.
BACKGROUND
[0002] Various embodiments generally may relate to the field of
wireless communications.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] FIG. 1 is a simplified plot illustrating a probability that
a Transmit/Receive Point (TRP) detects a correct beamforming vector
for each UE.
[0004] FIG. 2 is a simplified plot of cumulative distribution
functions of the network spectral efficiency of a multi-user
multiple input multiple output (MU-MIMO) millimeter wave (mm-wave)
system, according to some embodiments.
[0005] FIG. 3 is a simplified signal flow diagram illustrating a
measurement, feedback, and estimation protocol in a wireless
communication system, according to some embodiments.
[0006] FIG. 4 is a simplified illustration of a comparison of a
number of measurements to select a beam using a sector level sweep
and a proposed method, which is disclosed herein.
[0007] FIG. 5 is a simplified plot illustrating a probability that
a receive node detects the beam that maximizes the beamforming gain
over the number of taken samples, according to some
embodiments.
[0008] FIG. 6 is a simplified signal flow diagram illustrating
signaling for receive node selection in a wireless communication
system, according to some embodiments.
[0009] FIG. 7 is a simplified diagram illustrating capture of
information about receive beams in a system using a receive
sector-level sweep (RXSS) system and a system according to the
proposed method.
[0010] FIG. 8 is a simplified view of a wireless network, according
to some embodiments.
[0011] FIG. 9 is a simplified illustration of a frame structure,
according to some embodiments.
[0012] FIG. 10 is a simplified signal flow diagram illustrating a
CSI acquisition scheme, according to some embodiments.
[0013] FIG. 11 illustrates an architecture of a system of a network
in accordance with some embodiments.
[0014] FIG. 12 illustrates example components of a device in
accordance with some embodiments.
[0015] FIG. 13 illustrates example interfaces of baseband circuitry
in accordance with some embodiments.
[0016] FIG. 14 is an illustration of a control plane protocol stack
in accordance with some embodiments.
[0017] FIG. 15 illustrates components of a core network in
accordance with some embodiments.
[0018] FIG. 16 is a block diagram illustrating components,
according to some example embodiments.
[0019] FIG. 17 is a simplified flowchart illustrating a method of
operating a wireless communication node, according to some
embodiments.
[0020] FIG. 18 is a simplified flowchart illustrating a method of
operating a wireless communication device, according to some
embodiments.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0021] The following detailed description refers to the
accompanying drawings. The same reference numbers may be used in
different drawings to identify the same or similar elements. In the
following description, for purposes of explanation and not
limitation, specific details are set forth such as particular
structures, architectures, interfaces, techniques, etc. in order to
provide a thorough understanding of the various aspects of various
embodiments. However, it will be apparent to those skilled in the
art having the benefit of the present disclosure that the various
aspects of the various embodiments may be practiced in other
examples that depart from these specific details. In certain
instances, descriptions of well-known devices, circuits, and
processes are omitted so as not to obscure the description of the
various embodiments with unnecessary detail. For the purposes of
the present document, the phrase "A or B" means (A), (B), or (A and
B).
[0022] With an increasing number of antennas per network node
advanced channel adaptive transmit strategies, like multi-user
multiple input multiple output (MIMO) (MU-MIMO) or coordinated
multi-point transmission (CoMP), are key to increasing the spectral
efficiency of wireless networks. To implement advanced channel
adaptive transmit strategies, information about the wireless
channels (e.g., channel state information (CSI)) may be acquired by
the transmitting nodes (sometimes referred to herein as
"Transmit/Receive Points" (TRPs)). An example of a TRP is a
cellular base station or Radio Access Network (RAN) node (e.g., an
evolved NodeB (eNB), a next generation NodeB (gNB), etc.).
[0023] Embodiments disclosed herein may address measuring,
estimating and feeding back CSI in multi-user massive MIMO systems.
Embodiments may facilitate the measurement and feedback overhead to
a minimum to efficiently implement advanced channel adaptive
transmit strategies.
[0024] Challenges exist in addressing measuring, estimating and
feeding back CSI for multi-user massive MIMO systems. In 3GPP, beam
management and CSI feedback are two procedures. Beam management is
defined by a set of L1/L2 procedures to acquire and maintain a set
of TRP(s) and/or UE beams that can be used for downlink (DL) and
uplink (UL) transmission and reception. Given a beam configuration,
CSI measurements are performed and transmit parameters are
determined. Since the beams are fixed before a scheduling decision
is made, transmit strategies that require a joint optimization of
beams and other transmit parameters cannot be implemented. In
legacy implementations, flexibility of transmitters and therefore
implementation of advanced channel adaptive transmit schemes may be
limited. Another legacy implementation involves Wireless Gigabit
(WiGig).
[0025] The beam refinement protocol (BRP) takes significant effort
to measure the channel matrix at the receivers such that beams can
be optimized. In legacy implementations, this may not scale well
with the number of antennas. The required number of measurement
signals scales linearly with the number of antennas.
[0026] Legacy implementations may address measurement, estimation,
quantization and the feedback separately: [0027] To measure the
wireless channel, reference signals (RS) may be transmitted from
all antenna ports using orthogonal resources such that the channels
between any antenna port pair can be measured. [0028] The
measurements are used by the UE to estimate some representation of
the wireless channel. [0029] Significant effort is taken by the UE
to quantize the channel estimations. [0030] Finally, CSI is
transmitted back to the TRP which decides on the transmit
parameters based on the information.
[0031] Legacy academic approaches may apply compressive sensing to
the problem of massive MIMO channel estimation and references
therein. Such approaches rely on the sparsity of the channel and
aim to reconstruct the entire channel. Legacy algorithms used to
decode compressed sensing measurements may be computationally too
complex to enable efficient real-time implementations. Moreover,
legacy compressed sensing based approaches rely on the assumption
that certain structures are available in the channels and typically
fail, if such structures change or are absent.
[0032] Embodiments disclosed herein may include processes to
measure, feedback, and infer from CSI. In some embodiments, a
measurement protocol that uniformly samples the channel space, and
at the same time performs a dimensionality reduction of the channel
space, may be implemented. In some embodiments, the receiver may
not attempt to estimate the channel. Rather, the receiver may
mirror measurements back to the transmitter. In some embodiments,
the transmitter may find transmit parameters by estimating a
scheduling metric without reconstructing the channel space (e.g., a
channel matrix).
[0033] Embodiments of the disclosure may have one or more of the
following advantages: [0034] Scaling with the number of transmit
antennas. For example, TRPs with a large number (e.g., thousands)
of transmit antennas may be supported. [0035] Measurement overhead
can be reduced, for example by up to 90%, compared to legacy
implicit and explicit feedback schemes. Sufficient measurements of
the channel may be generated without having to transmit orthogonal
RS from each antenna port. [0036] A different beamforming codebook
may be used in the measurement phase. Hence, measurement and
transmit codebooks can be optimized for their intended purpose. For
example, the transmit codebook can be optimized for coverage and
beamforming gain without constraining the number of elements. The
measurement codebook can be optimized to enable accurate
estimations with a minimum number of measurements. [0037] The
channel estimation complexity may be significantly reduced and the
UE may not implement complex channel estimation procedures.
Complexity and latency at the UE may be reduced. Computationally
complex tasks are moved to the TRP (i.e., infrastructure). [0038] A
TRP may have all degrees of freedom for user scheduling and network
control. Processing at the TRP can be performed by linear real-time
capable estimation schemes.
[0039] As will be discussed below, in some embodiments, a
measurement and feedback protocol may enable the network to perform
very close to optimal MU-MIMO with ideal CSI. For example, consider
the following system setup in Table 1:
TABLE-US-00001 TABLE 1 # TRP RF 8 # TRP antenna 128 (16 per RF) #
UE antenna 1 # UE 4 Channel model 3GPP Line of Sight (LOS) Transmit
codebook OFT codebook with 128 elements Measurement codebook Random
codebook with M (parameter) elements Carrier frequency 73 GHz
Transmit SNR -20 dB Rx SNR of 5th percentile .apprxeq.4 dB
Scheduler Greedy max rate
[0040] FIG. 1 is a simplified plot 100 illustrating a probability
that a TRP detects a correct beamforming vector (e.g., the
beamforming vector with a maximal beamforming gain) for each UE.
The plot 100 includes a first plot 102 corresponding to a
measurement plus quantization noise of negative infinite decibels
(-.infin. dB), a second plot 104 corresponding to a measurement
plus quantization noise of negative fifteen decibels (-15 dB), and
a third plot 106 corresponding to a measurement plus quantization
noise of negative ten decibels (-10 dB). The x-axis (horizontal
axis) shows the reduction of the measurement overhead ratio
compared to a beam sweeping scheme with 128 beams (which may
include 128 measurements). The y-axis (vertical axis) shows a
detection probability. As illustrated in the plot 100, with -15 dB
(or less) measurement-plus-quantization noise (the second plot
104), the measurement and feedback overhead can be reduced by
nearly 90% without sacrificing much detection probability.
[0041] FIG. 2 is a simplified plot 200 of cumulative distribution
functions 202, 204, 206, 208, 210, and 212 (CDFs 202, 204, 206,
208, 210, and 212) of the network spectral efficiency of a MU-MIMO
millimeter wave (mm-wave) system, according to some embodiments.
The parameters of the system are as indicated above in Table 1. The
CDFs 202, 204, 206, 208, 210, and 212 correspond to numbers 4, 8,
16, 32, 64, and ideal CSI 128 of resource signals (RS),
respectively. In some embodiments, scheduling may be performed in a
greedy fashion based on signal-to-interface-plus-noise ratio (SINR)
estimations. In some embodiments, the measurement and feedback
noise may be assumed to be zero. In some embodiments, the greedy
scheduler may schedule multiple UEs on the same resource as long as
the estimated spectral efficiency increases. In some embodiments,
the users may be separated in the spatial domain through a
wide-band analog codebook based beamforming and digital sub-band
zero forcing.
[0042] In some embodiments, sixteen reference signals (16 RS)
(corresponding to CDF 206) may provide sufficient information to
achieve performance very close to ideal CSI. In some embodiments,
this may reduce the measurement and feedback overhead
significantly, since legacy beam management schemes involve 128
measurements. Hence, in some embodiments, an overhead reduction of
87.5% may be achieved.
[0043] For example, consider a wireless network having a single TRP
and multiple UEs. In this example, it is assumed that each of the
UEs has a single receive antenna and the TRP is equipped with a
number N of antennas. For the ease of presentation, assume a block
fading channel model such that the channel from the TRP to UE can
be given by the vector h.sub.i.di-elect cons.C.sup.N. In some
embodiments, a protocol may be tailored for a scenario where the
TRP uses linear beamforming and possible beamforming vectors w are
defined by a codebook C.OR right.C.sup.N. Note that most
beamforming schemes with a limited feedback constraint can be
stated as beamforming schemes with a fixed transmit codebook.
[0044] In some embodiments, the TRP may optimize a channel adaptive
transmit strategy without estimating the channels at the UEs or the
TRP. In some embodiments, this may be enabled by feeding back
certain measurements from the UE to the TRP. An example
implementation of some such embodiments of measurement, feedback
and estimation protocols is illustrated in FIG. 3.
[0045] FIG. 3 is a simplified signal flow diagram illustrating a
measurement, feedback, and estimation protocol in a wireless
communication system 300, according to some embodiments. The
wireless communication system 300 includes a TRP 302 and a UE 304.
These and some related embodiments may be summarized as follows:
[0046] The TRP 302 may transmit 306, to the UE 304, a sequence of
RSs (e.g., non-orthogonal RSs) from all antenna ports
simultaneously. [0047] The UE 304 may measure 308 received signals
(e.g., received in a CSI-RS slot) resulting from the RSs. [0048]
The UE 304 may directly quantize 310 the received signals. [0049]
The UE 304 may feedback 312 the measurements to the TRP. [0050] The
TRP 302 may estimate 314 a scheduling utility function (also
referred to herein as "network utility function") that depends on
certain network parameters (e.g., a certain transmit strategy,
number of select users, assignment of users to precoding vectors,
etc.). [0051] The TRP 302 performs 316 network control. [0052] The
TRP 302 transmits a demodulation reference signal (DMRS) to the UE
304. [0053] The UE 304 decodes 320 the DMRS. [0054] The UE 304
estimates 322 channels. [0055] The UE 304 equalizes 324 the signal.
[0056] The UE 304 decodes 326 data from the signal.
[0057] Aspects of embodiments that address measurement, feedback
and estimation protocol in more detail are given below. For ease of
presentation, the aspects may focus on a base-band channel model.
Extensions to wideband channel models or two other models, however,
may be used in some embodiments.
Embodiments with Respect to Measurement
[0058] In some embodiments, in the measurement phase the TRP 302
may use a number M of resource elements (denoted as CSI-RS ports)
to transmit a sequence of M RSs from all (or a subset of) antenna
ports simultaneously. For example, assuming N antenna ports are be
used to transmit the pilot signals (e.g., the RSs), the signal that
is transmitted on the m-th resource element may be expressed by the
N dimensional row vector .0..sub.m.di-elect cons.C.sup.1.times.N.
The j-th element of the transmitted pilot signal .0..sub.mj can be
given by some complex number that is transmitted on the j-th
antenna element on the m-th resource element. All M pilot signals
are collected in a so-called measurement matrix
.0.=(.0..sub.1.sup.T, . . . , .0..sub.M.sup.T).sup.T.di-elect
cons.C.sup.M.times.N. For embodiments disclosed herein, the
measurement matrix is an M.times.N matrix and M<<N. Most
legacy schemes (like the BRP in WiGig) assume that the measurement
matrix .0. is an orthonormal N.times.N matrix.
Embodiments with Respect to Feedback
[0059] In some embodiments, to describe the feedback protocol, an
arbitrary but fixed UE may be considered. The signal received by
the UE in the m-th CSI-RS port may be given by
y.sub.im=.0..sub.mh.sub.i+n.sub.im=.SIGMA..sub.j.0..sub.mjh.sub.ij+n.sub.-
im, where n.sub.im is additive noise. The M dimensional measurement
vector containing all received signals from all CSI-RS ports can be
written as y.sub.i=.0.h.sub.i+n.sub.i.di-elect
cons.C.sup.M.times.1. In some embodiments, the vector y.sub.i may
be directly quantized and fed back to the TRP such that the
feedback message from UE i available to TRP may be
z.sub.i=y.sub.i+q.sub.i, where q.sub.i may be additional
quantization noise.
[0060] These embodiments are in contrast to legacy feedback schemes
that use the measurement vector y to estimate the channel or some
representation of the channel prior to generating the feedback
message. As a result, in some embodiments UEs having less
computational capability than legacy UEs may be used.
Embodiments with Respect to Estimation
[0061] In some embodiments, based on the feedback messages z.sub.i
from multiple UEs i=1, 2, . . . , K the TRP can estimate a variety
of utility functions. In some embodiments, a utility function that
may depend on the effective channel gains |h.sub.i.sup.Hw|, with
the channel h.sub.i and the beamforming vector w, can be estimated.
This may be facilitated by defining a function f(z.sub.i, w),
depending on the quantized measurements z.sub.i and the beamforming
vector w, that may approximate the effective channel gains
|h.sub.i.sup.Hw|.apprxeq.f(z.sub.i, w). Examples may include the
signal to interference noise ratio (SINR), which may be given
by
SINR i = h i H w i 2 1 + h i H w j 2 .apprxeq. f ( z i , w i ) 2 1
+ j .noteq. i f ( z j , w j ) 2 , ##EQU00001##
where w.sub.i is the beamforming vector assigned to UE i and
w.sub.j are beamforming vectors assigned to UEs scheduled on the
same resource element.
[0062] In some embodiments, another example may be the leakage
interference power .SIGMA..sub.j.noteq.1f(z.sub.j, w.sub.j).sup.2.
The function f(z.sub.j, w.sub.j) can be realized in many ways. This
function can be given by a linear function of the form f(z.sub.j,
w.sub.j)=|(.PSI.z.sub.i).sup.Hw|, where .PHI. is an N.times.M
matrix that may depend on the measurement matrix .0..
[0063] Another class of functions may be given by convex
optimization algorithms like the constrained l.sub.1 minimization,
which is commonly found in the context of compressed sensing
applications.
[0064] Machine learning algorithms can also be used to realize
estimation functions. In this case, the function may be trained or
learned based on a training set. Ultimately the estimation function
may depend on the available background information, the
computational capabilities of the TRP, and other side constraints
like the desired estimation latency or accuracy.
[0065] Receive Beam Management
[0066] Wireless transceivers with a large number of physical
antennas will be employed in future wireless systems. The high
power consumption and cost of radio frequency (RF) chains prevents
using traditional digital MIMO baseband beamforming techniques.
Hybrid digital-analog beamforming schemes divide the beamforming
between the analog and digital domain. In the analog domain
beamforming schemes can be implemented using both power and cost
efficient techniques. Since the analog beamforming processing
happens before the RF chain and the analog to digital converter
(ADC), the signal received at a single antenna cannot be observed.
The signal can only be observed after analog receive beamforming.
Consequently, the MIMO channel cannot be directly measured at the
receiver. To determine the optimal receive filter, a codebook of
receive beamforming vectors is defined and an exhaustive search
over all codebook elements is performed. To fully exploit the
combining gain, the number of codebook elements is usually in the
order of the number of physical receive antennas. Therefore, the
measurement overhead scales with the number of receive antennas
and, for a large number of antennas, causes significant pilot
signal overhead.
[0067] The core of most legacy solutions is to define a codebook of
receive beamforming vectors and to perform an exhaustive search
over all codebook elements (e.g., sector level sweep). More
efficient solutions perform the search in multiple stages.
[0068] In WiGig a sector level sweep is used to determine the
optimal receive beamforming vector. A so-called beam refinement
protocol (BRP) is used to further refine the beamforming vectors.
The BRP involves transmitting another sequence of reference signals
such that the receiver can measure the effective channel after
analog receive beamforming.
[0069] In 3GPP new radio (NR) it has been agreed that a set of
L1/L2 procedures to acquire and maintain a set of transmit and
receive beams will be specified. Most likely first implementations
will rely on a sector level sweep.
[0070] In academia there have been many proposals to apply
compressive sensing to the problem of massive MIMO channel
estimation. These approaches typically rely on the structure or
sparsity of the channel, and usually aim to reconstruct the entire
channel matrix or channel covariance matrix.
[0071] The problem of transmit beam management based on a
compressed measurement protocol has been considered. A compressed
sensing inspired scheme has been proposed that adopts a compressed
sensing based measurement protocol but on the reconstructions side
relies on simple linear schemes. This scheme reduces the number of
measurements significantly (e.g., up to 90%) but at the same time
enables the transmitter to detect the optimal analog transmit
beamforming vectors, with high probability.
[0072] Legacy solutions proposed in WiGig and 3GPP utilize either a
vast measurement overhead or limit the flexibility of the receiver
significantly.
[0073] Beamforming training in IEEE 802.11ad WiGig is divided in
two phases. First, during a sector-level sweep (SS), initial
transmit/receive beams are determined. In a subsequent beam
refinement phase (BRP) the selected beams are refined. In 3GPP NR
SS based procedures are under discussion for beam training. BRP is
not precluded. Note that in some solutions receive SS is also
considered an important step towards acquiring the initial UE
receive beamforming direction, as it avoids the UE scanning a large
number of directions in the responder SS phase in WiGig.
[0074] During a receive sector-level sweep (RXSS) the transmit node
transmits RS on the best known transmit beam to allow the receive
node to test for the optimum receive beam. Potential receive beams
are defined by a beamforming codebook with a number N.sub.CB of
elements. For each receive beam measurement at least one RS needs
to be transmitted by the transmit node. Therefore, receive
beamforming codebooks are usually designed to have a small number
of elements.
[0075] Algorithms used to decode compressed sensing measurements
are computationally too complex to enable efficient real-time
implementations. Moreover, compressed sensing based approaches rely
on the assumption that certain structures (e.g., sparsity, low
rankness) are available in the channels and typically fail, if such
structures are absent.
[0076] Disclosed herein are methods and related apparatuses and
systems that enable the receiver to determine the optimal receive
beamforming vector from a codebook with N.sub.CB elements by taking
a much smaller number of measurements M<<N.sub.CB. The
determination of the optimal receive beamforming vector may be made
without prior knowledge of previously used receive beamforming
vectors or location information. Prior knowledge, however, can be
used to further reduce the number of measurements.
[0077] Embodiments disclosed herein significantly reduce the
measurement overhead. In fact, the number of resources that need to
be allocated for beam management can be significantly smaller than
the number of potential receive beams. As will be discussed below,
the measurement overhead can be reduced by up to about 96% as
compared to an exhaustive search.
[0078] Embodiments disclosed herein are designed for application in
massive MIMO systems, including 3GPP NR and IEEE 802.11ad WiGig.
These embodiments minimize the measurement overhead to a minimum to
efficiently implement channel adaptive receive strategies, such as
hybrid analog-digital beamforming.
[0079] Embodiments disclosed herein allow the receive node (e.g.,
the UE) to determine an optimal receive beam from a beamforming
codebook without measuring each potential receive beam. The number
of measurements that are performed in such embodiments can be much
smaller than the number of potential receive beams. In fact, the
number of codebook elements N.sub.CB (i.e., potential receive
beams) can be made very large without the need to increase the
number of measurements.
[0080] FIG. 4 is a simplified illustration of a comparison of a
number of measurements to select a beam using a sector level sweep
400A and a proposed method 400B, which is disclosed herein. FIG. 4
compares measurement overhead and codebook size. As illustrated in
FIG. 4, in the sector level sweep 400A, N.sub.CB measurements 402A
are used to select one selected beam 406A out of N.sub.CB beams
404A. As also illustrated in FIG. 4, in the proposed method 400B,
only M measurements 402B are used to select one beam 406B out of
N.sub.CB beams (e.g., M may be much smaller than N.sub.CB). As
illustrated in FIG. 4, the proposed method 400B enables selection
using fewer measurements, and with a higher resolution codebook
(CB) (e.g., higher number of beam entries in the codebook) as
compared to the selector level sweep 400A.
[0081] The number of measurements 402B used in the proposed method
400B is also smaller than what is used in a BRP, which is discussed
above. Table 2 below compares the number of measurements used for
selecting a beam in RXSS, receive BRP (RX BRP), and the proposed
method.
TABLE-US-00002 TABLE 2 RXSS RX BRP Proposed method #Measurements
N.sub.CB N.sub.R M (M << N.sub.R and M << N.sub.CB)
[0082] A simulation illustrates advantages of the proposed method.
Parameters and configurations of this numeric evaluation are shown
below in Table 3. Results of the simulation are illustrated in FIG.
5.
TABLE-US-00003 TABLE 3 # TX antennas 256 in a uniform linear array
(ULA) # RX antenna {64, 256, 1024} (ULA) Channel model 3GPP LOS TX
codebook DFT RX codebook DFT SNR -20 dB Post BF SNR 0 dB
[0083] FIG. 5 is a simplified plot 500 illustrating a probability
that a receive node (e.g., a UE) detects the beam that maximizes
the beamforming gain over the number of taken samples M, according
to some embodiments. The plot 500 includes a plot 510 of an
embodiment including N.sub.R=64 receive antennas, a plot 520 of an
embodiment including N.sub.R=256 receive antennas, and a plot 530
of an embodiment including N.sub.R=1024 receive antennas.
Independent of the number of receive codebook elements N.sub.CB,
which is equal to the number of receive antennas N.sub.CB=N.sub.R,
the number of measurements used for detection probability 90% is
M.gtoreq.30. In other words, thirty measurements are sufficient
independent of the number of receive antennas. This translates into
a remarkable reduction of the number of measurements as compared to
legacy systems, as summarized in Table 4 below. Table 4 indicates
measurement overhead reduction for different numbers of receive
antennas and a DFT receive codebook with a number of codebook
entries being equal to the number of receive antennas
(N.sub.CB=N.sub.R).
TABLE-US-00004 TABLE 4 #RX antennas 64 256 1024 Measurement
overhead reduction 60% 88% 96%
[0084] Embodiments of the disclosure may also be used to: [0085]
Detect if the wireless channel is in a line of sight (LOS) state or
no line of sight (NLOS) state, including to detect if the receive
node is experiencing a blockage event. [0086] Detect receive beams
that are vulnerable to strong interference from another transmit
node.
[0087] Consider a single link of a wireless network with a single
transmit and receive node. For the ease of presentation we consider
a single receive and a single stream transmission, but point out
that extensions to multiple receive nodes and/or multi-stream
transmissions can be realized by performing the described actions
at each receive node and for each stream. Similarly, if the receive
node is equipped with multiple receive panels, the described method
can be utilized for each receive panel. An initial handshaking may
be assumed to have been performed, and the transmit node has
determined a transmit beam that provides a reasonable channel
gain.
[0088] Embodiments of the disclosure enable a receive node to
determine an optimal receive beam from a possibly large codebook
without the need to perform a measurement for each potential beam.
In fact, the number of measurements M that need to be performed can
be much smaller than the number of potential receive beams
(M<<N.sub.CB), as illustrated in FIG. 5.
[0089] FIG. 6 is a simplified signal flow diagram illustrating
signaling for receive node selection in a wireless communication
system 600, according to some embodiments. It is assumed that a
receive node 604 has N.sub.R antennas and the transmit node 602 is
equipped with N.sub.T antennas. For the ease of presentation assume
a base band channel model such as that for a fixed discrete time
and frequency, the channel between the transmit node 602 and the
receive node 604 can be given by the N.sub.R.times.N.sub.T matrix
H. Let w be the beamforming vector used by the transmit node to
transmit towards the receive node.
[0090] The proposed compressed receive beam management scheme can
be divided into the following acts, as illustrated in FIG. 6:
[0091] Uniformly sample the receive beam space. As illustrated in
FIG. 6, the transmit node 602 transmits 606 pilot signals (e.g.,
beamformed CSI-RS or PSS/SSS), and the receive node 604 samples 608
the transmit beam space. Although FIG. 6 shows three of these pilot
signals transmitted 606, there may be more or less. By way of
non-limiting example, the number M of these samples may be about
30, as discussed above with reference to FIG. 5. [0092] Signal 610
an acknowledgment (ACK), from the receive node 604 to the transmit
node 602, if the quality of samples is sufficient. This act may be
optional. [0093] Use samples to detect 612 a best receive beam from
the codebook. [0094] Transmit node 602 transmits 614 data to the
receive node 604. [0095] Receive 616 data from the transmit node
602 by the receive node 604.
[0096] The reminder of this Section is used to describe each act of
FIG. 6 in detail.
[0097] RX Beam Space Sampling
[0098] To enable the receive node 604 to determine 612 a good
receive beam the transmit node 602 transmits 606 a sequence of M RS
symbols. The receive signal of the i-th measurement can be written
as y.sub.i=a.sub.iHw+n.sub.i, where a.sub.i is the i-th measurement
combining vector. After performing M measurements the vector of
measurements is:
y=AHw+n
[0099] The measurement combing vectors a.sub.i are designed such
that each measurement captures information about a large fraction
of the receive beam space. In contrast, during the standard RXSS
protocol each measurement only captures information for one beam
from the codebook. FIG. 7 illustrates differences between these
approaches.
[0100] FIG. 7 is a simplified diagram illustrating capture of
information about receive beams 730A, 730B in a system 700A using
RXSS and a system 700B according to the proposed method. The system
700A includes a transmit node 702A and a receive node 704A. When
the transmit node 702A transmits a transmit beam 720A including a
pilot signal in the system 700A using RXSS, only information for a
single one of the receive beams 730A (corresponding to a single one
of the codebook elements) is provided to the receive node 704A. In
other words, each measurement captures information for one codebook
element.
[0101] The system 700B of the proposed method includes a transmit
node 702B and a receive node 704B. When the transmit node 702B
transmits a transmit beam 720B including a pilot signal in the
system 700B, information for a large fraction of the receive beam
space 730B is received by the receive node 704B. In other words,
each measurement captures information of a large fraction of the
receive beam space.
[0102] ACK Signaling
[0103] To determine if a sufficient number of samples have been
collected, each sample is classified as class A (useful) or class B
(not useful). Once a given number of measurements has been
collected, an ACK is signaled (e.g., reference character 610 of
FIG. 6) and the receive beam detection process is triggered. The
required number of class A samples may be configured by the network
or determined in a warm-up phase. The receive node may also
report/indicate the number of RXSS resources (one resource per RXSS
measurement). As a result, the receive nodes implemented according
to embodiments of the disclosure can request fewer UE-RXSS resource
than a legacy UE.
[0104] Detect Best RX Beam
[0105] Based on samples y the receive node can estimate different
metrics that can be used to determine the best receive beam. In
general, any metric that depends on the effective channel gains
|u.sup.HHw|, with the channel H, transmit beam w, and potential
receive beam u, can be estimated. This is enabled by defining a
function g(y, u) that depends on the samples y and a potential
receive beam u. The function is chosen to approximate the effective
channel gain |u.sup.HHw|.apprxeq.g(y, u). The best receive beam can
be found by solving the combinatorial optimization problem:
max u .di-elect cons. C g ( y , u ) ##EQU00002##
where the beamforming codebook is given by C. The function g(y, u)
can be realized in different ways. It can be given by a linear
function of the form:
g(y,u)=|u.sup.HBy|,
where B is an N.sub.R.times.M matrix possibly depending on the
sampling matrix A.
[0106] Another class of functions may be given by convex
optimization algorithms like the constrained l.sub.1 minimization
commonly found in the context of compressed sensing
applications.
[0107] Machine learning algorithms can also be used to realize
estimation functions. In this case the function may be trained or
learned based on a training set. Ultimately the estimation function
shall depend on the available background information, the
computational capabilities of the receive node, or other side
constraints.
[0108] Efficient Interference Management
[0109] Consider the downlink of a wireless network with a large
number of transmit and receive nodes. Assume that the transmit
nodes are connected via a backhaul network that enables fast and
reliable sharing of scheduling information, acquired channel state
information, and in some embodiments also data sharing. The
backhaul network connects all transmit nodes to a central control
node that performs radio resource management (RRM). Let the network
be sufficiently dense such that with high probability each receive
node is within the coverage area of multiple transmit nodes. Assume
also that every node is equipped with a large number of antennas
(i.e., massive MIMO). To fully exploit the potential of dense
wireless networks, transmit nodes acquire channel state information
(CSI) from receive nodes within their coverage area. CSI may be
used for: [0110] Radio resource management (beam management,
scheduling, link adaption, etc.) [0111] Interference management
[0112] Handovers from one transmit node to another [0113] Enabling
multi-connectivity
[0114] Acquiring CSI (channel state information) in dense wireless
systems with a massive number of antennas is a challenging problem.
First, with a large number of transmit antennas using orthogonal
resources to measure the channel between any transmit/receive
antenna pair is infeasible. Second, wireless systems operating
above 6 GHz are likely to employ hybrid digital analog (HDA)
transceiver architectures. With an HDA architecture, measuring the
signal between any pair of transmit and receive antennas is not
possible.
[0115] Explicit Feedback
[0116] Legacy systems employed explicit feedback of the channel
matrix or some function of the channel matrix (e.g., the channel
covariance matrix). To measure the channel between a transmit node
and receive nodes within the coverage area, pilot signals are
broadcasted. To avoid interference between transmit nodes and
transmit antennas from the same transmit node, pilot signals are
transmitted on orthogonal resources (e.g., different time-frequency
resources).
[0117] Feedback of Preferred Beamforming Vector
[0118] If the beamforming vectors are defined by a codebook, each
transmit node may broadcast beamformed pilots, such that each
receive node within the coverage area can determine and feed back a
set of preferred beamforming vectors. To avoid interference between
transmit nodes, pilot signals are transmitted on orthogonal
resources (e.g., different time-frequency resources).
[0119] Another approach to minimize training and feedback overhead
is based on receive node location information. Yet another approach
is based on learning techniques that exploit channel correlations
of neighboring TX nodes.
[0120] Explicit feedback and feedback of a preferred beamforming
vector use pilot signals to be transmitted on orthogonal resources
(e.g., different time-frequency resources). Using orthogonal pilot
resources does not scale well with the number transmit nodes, nor
with the number of transmit antennas. These schemes impose an
excessive measurement and feedback overhead.
[0121] Location based approaches do not perform well in
non-line-of-sight scenarios. Moreover, obtaining accurate estimates
of the effective channel gain based on location information may not
be possible.
[0122] Learning based techniques that exploit correlations of
neighboring transmit nodes use extensive training overhead to
achieve the high CSI accuracy required for tasks such as radio
resource management, or other tasks outlined above.
[0123] In some embodiments, disclosed herein are systems that use
only a small number of coordination cluster specific reference
signals to be transmitted. In some embodiments, a sampling and
signaling scheme that conveys compressed CSI from receive nodes to
transmit nodes and the central controller is disclosed. In some
embodiments, an efficient decompression scheme estimates relevant
system parameters (e.g., effective channel gains, SINR, strongest
interferer, etc.) from compressed CSI measurements. Advantages of
these approaches include: [0124] The measurement overhead is
significantly reduced since all transmit nodes simultaneously sense
the channel using the same spectral resources. [0125] The sensing
scheme is non-adaptive (cell/cluster specific) in the sense that
the measurement signals can be used by all receive nodes
simultaneously. [0126] RRM has similar flexibility as under
state-of-the-art explicit feedback schemes. RRM has all degrees of
freedom choosing transmit parameters such as scheduled RX nodes,
beamforming vectors, modulation and coding schemes, etc.
[0127] FIG. 8 is a simplified view of a wireless network 800,
according to some embodiments. In a downlink of the wireless
network 800, the wireless network 800 may include a number B of
transmit nodes 802 (e.g., base stations) and a number U of receive
nodes 804 (e.g., user equipment). Each transmit node 804 is
equipped with a number N.sub.B of antennas and each receive node
804 is equipped with a number N.sub.U of receive antennas.
[0128] The transmit nodes 802 may be communicatively coupled to a
central control node 806 via a high-capacity and low-latency
backhaul network 808. Each of the transmit nodes 802 and the
central control node 806 may include a coverage area 810. The
central control node 806 performs radio resource management (RRM).
The network 800 is assumed to be sufficiently dense such that, with
high probability, each receive node 804 is within the coverage area
810 of multiple transmit nodes 802. It is assumed that the transmit
nodes 802 are grouped in coordination clusters and, for the ease of
presentation, consider a single coordination cluster. All transmit
nodes within a coordination cluster are synchronized on a symbol
level.
[0129] FIG. 9 is a simplified illustration of a frame structure
900, according to some embodiments. A frame 900 is divided into
subframes 910; a subframe 910 is divided into multiple slots 920;
and a slot includes multiple symbols 930 (e.g., OFDM or single
carrier symbols). Within a frame 900, certain slots 920 are
reserved for transmission of CSI-RS. The location of CSI-RS slots
920 is known to all transmit nodes 802 and receive nodes 804 (FIG.
8).
[0130] Referring once again to FIG. 8, it is assumed that when the
receive nodes 804 have successfully performed the initial access
procedure, the receive nodes 804 are attached to the network 800
and connected to RRM. The following discussion will discuss a
measurement phase, a feedback phase, and a scheduling and data
transmission phase. These phases will be discussed in conjunction
with FIG. 10.
[0131] FIG. 10 is a simplified signal flow diagram illustrating a
CSI acquisition scheme 1000, according to some embodiments.
[0132] Measurement Phase
[0133] Referring to FIGS. 8 and 10 together, in a given CSI-RS slot
i, the transmit nodes 802 simultaneously transmit 1010, to the
receive nodes 804, a sequence of M precoded RS signals
.0..sub.bi.di-elect cons..sup.N.sup.b (transmit node b) i=1, . . .
, M. The i-th RS signal received 1020 by receive node 804 u can be
written as:
y.sub.ui=.SIGMA..sub.b=1.sup.Bv.sub.u*H.sub.ub.0..sub.bi+v.sub.u*n.sub.u-
,
with the receive filter v.sub.u.di-elect cons..sup.N.sup.u (assumed
to be fixed a priori), channel matrix H.sub.ub.di-elect
cons..sup.N.sup.U.sup..times.N.sup.B and additive noise
n.sub.u.di-elect cons..sup.N.sup.U. Defining the composite channel
matrix H.sub.uT=(H.sub.u1, H.sub.u2, . . . , H.sub.uB).di-elect
cons..sup.N.sup.U.sup..times.N.sup.B and the composite precoded
RS:
.0..sub.i=(.0..sub.1i.sup.T,.0..sub.2i.sup.T, . . .
,.0..sub.Bi.sup.T).di-elect cons..sup.BN.sup.B,
the received signal can be written as:
y.sub.ui=v.sub.u*H.sub.u.0..sub.i+v.sub.u*n.sub.u.
After receiving M precoded RS .PHI.=(.0..sub.1, .0..sub.2,
.0..sub.M) the vector of measurements collected by the receive node
u is:
y.sub.u=v.sub.u*H.sub.u.PHI.+v.sub.u*n.sub.u.
[0134] In contrast to legacy CSI acquisition schemes, the
measurement protocol uses no orthogonal pilots. In fact,
embodiments of the disclosure embrace non-orthogonal RS.
Non-orthogonal RS enable each receive node 804, for example u, to
measure 1020 a sequence of M projections v*H.sub.u.0..sub.ui of the
effective composite channel v.sub.u*H.sub.u. Under certain
conditions the measurement overhead M is significantly smaller than
with legacy channel acquisition schemes.
[0135] Feedback Phase
[0136] With continued reference to FIGS. 8 and 10, receive node u
804 selects 1030 measurements from the vector y.sub.u, quantizes
1040 them and feeds them back 1050 to any transmit node 802.
Transmit nodes 802 forward the feedback messages to the central
control node 806. Hence, the feedback message from the receive node
u 804 may be available to the central control node 806. This
feedback message can be given by z.sub.i=f(y.sub.u)+q.sub.i, where
the function f(y) selects certain measurements, and q.sub.i is
additional quantization noise. The function f(y) may select the
elements of y.sub.i that are above a certain threshold .epsilon.
(e.g., |z.sub.i|>.epsilon.).
[0137] The described feedback protocol differs from legacy feedback
schemes in the sense that legacy schemes use measurements to
estimate the channel or some representation of the channel prior to
generating the feedback message. As a consequence, embodiments
disclosed herein enable UEs (receive nodes 804) with less
computational capabilities to be employed.
[0138] Scheduling and Data Transmission Phase
[0139] Based on the feedback messages z.sub.u from multiple receive
nodes 804, the central control node 806 is enabled to estimate 1060
a variety of scheduling metrics. In general, any metric that
depends on the effective channel gains |H.sub.u*w|, with channel
h.sub.u*=v.sub.u*H.sub.u and beamforming vector w.di-elect cons.C
an element of a beamforming codebook, can be estimated. This is
enabled by defining a function .PSI.(z.sub.u, w), depending on the
quantized measurements z.sub.u and the beamforming vector w, that
approximates the effective channel gains
|h.sub.u*w|.apprxeq..PSI.(z.sub.u, w). Examples of scheduling
metrics include the SINR:
SINR u = h u * w u 2 1 + j .noteq. u h u * w u 2 .apprxeq. .PSI. (
z u , w u ) 2 1 + j .noteq. u .PSI. ( z u , w u ) 2 ,
##EQU00003##
where it is assumed that w.sub.i is the beamforming vector assigned
to receive node i 804 and w.sub.j are beamforming vectors assigned
to interfering UEs (e.g., receive nodes 804) scheduled on the same
resource element. Another example may be the leakage interference
power .SIGMA..sub.j.noteq.u.PSI.(z.sub.u, w.sub.u).sup.2, which may
be used for interference management.
[0140] The estimation function .PSI.(z.sub.u, w.sub.j) can be
realized in many ways. Ultimately the choice of .PSI.( , ) depends
on the structure of the composite channel matrix (i.e., low
rankness, sparsity, etc.), desired estimation accuracy,
computational power of the central controller, or other system
constraints (e.g., latency). The estimation function can be given
by a linear function of the form:
.PSI.(z.sub.i,w.sub.j)=|(.PSI.z.sub.i).sup.Hw|,
where .PSI. is a BN.sub.B.times.M matrix possibly depending on the
measurement matrix .PHI..
[0141] Another class of functions may be given by convex
optimization algorithms like the constrained l1 minimization
commonly found in the context of compressed sensing applications.
Also machine learning algorithms can be used to realize estimation
functions. In this case the estimation function may be trained or
learned based on a training set.
[0142] FIG. 11 illustrates an architecture of a system 1100 of a
network in accordance with some embodiments. The system 1100 is
shown to include a user equipment (UE) 1101 and a UE 1102. The UEs
1101 and 1102 are illustrated as smartphones (e.g., handheld
touchscreen mobile computing devices connectable to one or more
cellular networks), but may also comprise any mobile or non-mobile
computing device, such as Personal Data Assistants (PDAs), pagers,
laptop computers, desktop computers, wireless handsets, or any
computing device including a wireless communications interface.
[0143] In some embodiments, any of the UEs 1101 and 1102 can
comprise an Internet of Things (IoT) UE, which can comprise a
network access layer designed for low-power IoT applications
utilizing short-lived UE connections. An IoT UE can utilize
technologies such as machine-to-machine (M2M) or machine-type
communications (MTC) for exchanging data with an MTC server or
device via a public land mobile network (PLMN), Proximity-Based
Service (ProSe) or device-to-device (D2D) communication, sensor
networks, or IoT networks. The M2M or MTC exchange of data may be a
machine-initiated exchange of data. An IoT network describes
interconnecting IoT UEs, which may include uniquely identifiable
embedded computing devices (within the Internet infrastructure),
with short-lived connections. The IoT UEs may execute background
applications (e.g., keep-alive messages, status updates, etc.) to
facilitate the connections of the IoT network.
[0144] The UEs 1101 and 1102 may be configured to connect, e.g.,
communicatively couple, with a radio access network (RAN) 1110. The
RAN 1110 may be, for example, an Evolved Universal Mobile
Telecommunications System (UMTS), a Terrestrial Radio Access
Network (E-UTRAN), a NextGen RAN (NG RAN), or some other type of
RAN. The UEs 1101 and 1102 utilize connections 1103 and 1104,
respectively, each of which comprises a physical communications
interface or layer (discussed in further detail below); in this
example, the connections 1103 and 1104 are illustrated as an air
interface to enable communicative coupling, and can be consistent
with cellular communications protocols, such as a Global System for
Mobile Communications (GSM) protocol, a code-division multiple
access (CDMA) network protocol, a Push-to-Talk (PTT) protocol, a
PTT over Cellular (POC) protocol, a Universal Mobile
Telecommunications System (UMTS) protocol, a 3GPP Long Term
Evolution (LTE) protocol, a fifth generation (5G) protocol, a New
Radio (NR) protocol, and the like.
[0145] In this embodiment, the UEs 1101 and 1102 may further
directly exchange communication data via a ProSe interface 1105.
The ProSe interface 1105 may alternatively be referred to as a
sidelink interface comprising one or more logical channels,
including but not limited to a Physical Sidelink Control Channel
(PSCCH), a Physical Sidelink Shared Channel (PSSCH), a Physical
Sidelink Discovery Channel (PSDCH), and a Physical Sidelink
Broadcast Channel (PSBCH).
[0146] The UE 1102 is shown to be configured to access an access
point (AP) 1106 via connection 1107. The connection 1107 can
comprise a local wireless connection, such as a connection
consistent with any IEEE 802.11 protocol, wherein the AP 1106 would
comprise a wireless fidelity (WiFi.RTM.) router. In this example,
the AP 1106 may be connected to the Internet without connecting to
the core network of the wireless system (described in further
detail below).
[0147] The RAN 1110 can include one or more access nodes that
enable the connections 1103 and 1104. These access nodes (ANs) can
be referred to as base stations (BSs), NodeBs, evolved NodeBs
(eNBs), next Generation NodeBs (gNB), RAN nodes, and so forth, and
can comprise ground stations (e.g., terrestrial access points) or
satellite stations providing coverage within a geographic area
(e.g., a cell). The RAN 1110 may include one or more RAN nodes for
providing macrocells, e.g., macro RAN node 1111, and one or more
RAN nodes for providing femtocells or picocells (e.g., cells having
smaller coverage areas, smaller user capacity, or higher bandwidth
compared to macrocells), e.g., low power (LP) RAN node 1112.
[0148] Any of the RAN nodes 1111 and 1112 can terminate the air
interface protocol and can be the first point of contact for the
UEs 1101 and 1102. In some embodiments, any of the RAN nodes 1111
and 1112 can fulfill various logical functions for the RAN 1110
including, but not limited to, radio network controller (RNC)
functions such as radio bearer management, uplink and downlink
dynamic radio resource management and data packet scheduling, and
mobility management.
[0149] In accordance with some embodiments, the UEs 1101 and 1102
can be configured to communicate using Orthogonal
Frequency-Division Multiplexing (OFDM) communication signals with
each other or with any of the RAN nodes 1111 and 1112 over a
multicarrier communication channel in accordance various
communication techniques, such as, but not limited to, an
Orthogonal Frequency-Division Multiple Access (OFDMA) communication
technique (e.g., for downlink communications) or a Single Carrier
Frequency Division Multiple Access (SC-FDMA) communication
technique (e.g., for uplink and ProSe or sidelink communications),
although the scope of the embodiments is not limited in this
respect. The OFDM signals can comprise a plurality of orthogonal
subcarriers.
[0150] In some embodiments, a downlink resource grid can be used
for downlink transmissions from any of the RAN nodes 1111 and 1112
to the UEs 1101 and 1102, while uplink transmissions can utilize
similar techniques. The grid can be a time-frequency grid, called a
resource grid or time-frequency resource grid, which is the
physical resource in the downlink in each slot. Such a
time-frequency plane representation is a common practice for OFDM
systems, which makes it intuitive for radio resource allocation.
Each column and each row of the resource grid corresponds to one
OFDM symbol and one OFDM subcarrier, respectively. The duration of
the resource grid in the time domain corresponds to one slot in a
radio frame. The smallest time-frequency unit in a resource grid is
denoted as a resource element. Each resource grid comprises a
number of resource blocks, which describe the mapping of certain
physical channels to resource elements. Each resource block
comprises a collection of resource elements; in the frequency
domain, this may represent the smallest quantity of resources that
currently can be allocated. There are several different physical
downlink channels that are conveyed using such resource blocks.
[0151] The physical downlink shared channel (PDSCH) may carry user
data and higher-layer signaling to the UEs 1101 and 1102. The
physical downlink control channel (PDCCH) may carry information
about the transport format and resource allocations related to the
PDSCH channel, among other things. It may also inform the UEs 1101
and 1102 about the transport format, resource allocation, and H-ARQ
(Hybrid Automatic Repeat Request) information related to the uplink
shared channel. Typically, downlink scheduling (assigning control
and shared channel resource blocks to the UE 1102 within a cell)
may be performed at any of the RAN nodes 1111 and 1112 based on
channel quality information fed back from any of the UEs 1101 and
1102. The downlink resource assignment information may be sent on
the PDCCH used for (e.g., assigned to) each of the UEs 1101 and
1102.
[0152] The PDCCH may use control channel elements (CCEs) to convey
the control information. Before being mapped to resource elements,
the PDCCH complex-valued symbols may first be organized into
quadruplets, which may then be permuted using a sub-block
interleaver for rate matching. Each PDCCH may be transmitted using
one or more of these CCEs, where each CCE may correspond to nine
sets of four physical resource elements known as resource element
groups (REGs). Four Quadrature Phase Shift Keying (QPSK) symbols
may be mapped to each REG. The PDCCH can be transmitted using one
or more CCEs, depending on the size of the downlink control
information (DCI) and the channel condition. There can be four or
more different PDCCH formats defined in LTE with different numbers
of CCEs (e.g., aggregation level, L=1, 2, 4, or 8).
[0153] Some embodiments may use concepts for resource allocation
for control channel information that are an extension of the
above-described concepts. For example, some embodiments may utilize
an enhanced physical downlink control channel (EPDCCH) that uses
PDSCH resources for control information transmission. The EPDCCH
may be transmitted using one or more enhanced the control channel
elements (ECCEs). Similar to above, each ECCE may correspond to
nine sets of four physical resource elements known as enhanced
resource element groups (EREGs). An ECCE may have other numbers of
EREGs in some situations.
[0154] The RAN 1110 is shown to be communicatively coupled to a
core network (CN) 1120--via an S1 interface 1113. In embodiments,
the CN 1120 may be an evolved packet core (EPC) network, a NextGen
Packet Core (NPC) network, or some other type of CN. In this
embodiment the S1 interface 1113 is split into two parts: the S1-U
interface 1114, which carries traffic data between the RAN nodes
1111 and 1112 and a serving gateway (S-GW) 1122, and an S1-mobility
management entity (MME) interface 1115, which is a signaling
interface between the RAN nodes 1111 and 1112 and MMEs 1121.
[0155] In this embodiment, the CN 1120 comprises the MMEs 1121, the
S-GW 1122, a Packet Data Network (PDN) Gateway (P-GW) 1123, and a
home subscriber server (HSS) 1124. The MMEs 1121 may be similar in
function to the control plane of legacy Serving General Packet
Radio Service (GPRS) Support Nodes (SGSN). The MMEs 1121 may manage
mobility aspects in access such as gateway selection and tracking
area list management. The HSS 1124 may comprise a database for
network users, including subscription-related information to
support the network entities' handling of communication sessions.
The CN 1120 may comprise one or several HSSs 1124, depending on the
number of mobile subscribers, on the capacity of the equipment, on
the organization of the network, etc. For example, the HSS 1124 can
provide support for routing/roaming, authentication, authorization,
naming/addressing resolution, location dependencies, etc.
[0156] The S-GW 1122 may terminate the S1 interface 1113 towards
the RAN 1110, and routes data packets between the RAN 1110 and the
CN 1120. In addition, the S-GW 1122 may be a local mobility anchor
point for inter-RAN node handovers and also may provide an anchor
for inter-3GPP mobility. Other responsibilities may include lawful
intercept, charging, and some policy enforcement.
[0157] The P-GW 1123 may terminate an SGi interface toward a PDN.
The P-GW 1123 may route data packets between the CN 1120 (e.g., an
EPC network) and external networks such as a network including the
application server 1130 (alternatively referred to as application
function (AF)) via an Internet Protocol (IP) interface 1125.
Generally, an application server 1130 may be an element offering
applications that use IP bearer resources with the core network
(e.g., UMTS Packet Services (PS) domain, LTE PS data services,
etc.). In this embodiment, the P-GW 1123 is shown to be
communicatively coupled to an application server 1130 via an IP
communications interface 1125. The application server 1130 can also
be configured to support one or more communication services (e.g.,
Voice-over-Internet Protocol (VoIP) sessions, PTT sessions, group
communication sessions, social networking services, etc.) for the
UEs 1101 and 1102 via the CN 1120.
[0158] The P-GW 1123 may further be a node for policy enforcement
and charging data collection. A Policy and Charging Enforcement
Function (PCRF) 1126 is the policy and charging control element of
the CN 1120. In a non-roaming scenario, there may be a single PCRF
in the Home Public Land Mobile Network (HPLMN) associated with a
UE's Internet Protocol Connectivity Access Network (IP-CAN)
session. In a roaming scenario with local breakout of traffic,
there may be two PCRFs associated with a UE's IP-CAN session: a
Home PCRF (H-PCRF) within a HPLMN and a Visited PCRF (V-PCRF)
within a Visited Public Land Mobile Network (VPLMN). The PCRF 1126
may be communicatively coupled to the application server 1130 via
the P-GW 1123. The application server 1130 may signal the PCRF 1126
to indicate a new service flow and select the appropriate Quality
of Service (QoS) and charging parameters. The PCRF 1126 may
provision this rule into a Policy and Charging Enforcement Function
(PCEF) (not shown) with the appropriate traffic flow template (TFT)
and QoS class of identifier (QCI), which commences the QoS and
charging as specified by the application server 1130.
[0159] FIG. 12 illustrates example components of a device 1200 in
accordance with some embodiments. In some embodiments, the device
1200 may include application circuitry 1202, baseband circuitry
1204, Radio Frequency (RF) circuitry 1206, front-end module (FEM)
circuitry 1208, one or more antennas 1210, and power management
circuitry (PMC) 1212 coupled together at least as shown. The
components of the illustrated device 1200 may be included in a UE
or a RAN node. In some embodiments, the device 1200 may include
fewer elements (e.g., a RAN node may not utilize application
circuitry 1202, and instead include a processor/controller to
process IP data received from an EPC). In some embodiments, the
device 1200 may include additional elements such as, for example,
memory/storage, display, camera, sensor, or input/output (I/O)
interface. In other embodiments, the components described below may
be included in more than one device (e.g., said circuitries may be
separately included in more than one device for Cloud-RAN (C-RAN)
implementations).
[0160] The application circuitry 1202 may include one or more
application processors. For example, the application circuitry 1202
may include circuitry such as, but not limited to, one or more
single-core or multi-core processors. The processor(s) may include
any combination of general-purpose processors and dedicated
processors (e.g., graphics processors, application processors,
etc.). The processors may be coupled with or may include
memory/storage and may be configured to execute instructions stored
in the memory/storage to enable various applications or operating
systems to run on the device 1200. In some embodiments, processors
of application circuitry 1202 may process IP data packets received
from an EPC.
[0161] The baseband circuitry 1204 may include circuitry such as,
but not limited to, one or more single-core or multi-core
processors. The baseband circuitry 1204 may include one or more
baseband processors or control logic to process baseband signals
received from a receive signal path of the RF circuitry 1206 and to
generate baseband signals for a transmit signal path of the RF
circuitry 1206. Baseband processing circuitry 1204 may interface
with the application circuitry 1202 for generation and processing
of the baseband signals and for controlling operations of the RF
circuitry 1206. For example, in some embodiments, the baseband
circuitry 1204 may include a third generation (3G) baseband
processor 1204A, a fourth generation (4G) baseband processor 1204B,
a fifth generation (5G) baseband processor 1204C, or other baseband
processor(s) 1204D for other existing generations, generations in
development or to be developed in the future (e.g., second
generation (2G), sixth generation (6G), etc.). The baseband
circuitry 1204 (e.g., one or more of baseband processors 1204A-D)
may handle various radio control functions that enable
communication with one or more radio networks via the RF circuitry
1206. In other embodiments, some or all of the functionality of
baseband processors 1204A-D may be included in modules stored in
the memory 1204G and executed via a Central Processing Unit (CPU)
1204E. The radio control functions may include, but are not limited
to, signal modulation/demodulation, encoding/decoding, radio
frequency shifting, etc. In some embodiments,
modulation/demodulation circuitry of the baseband circuitry 1204
may include Fast-Fourier Transform (FFT), precoding, or
constellation mapping/demapping functionality. In some embodiments,
encoding/decoding circuitry of the baseband circuitry 1204 may
include convolution, tail-biting convolution, turbo, Viterbi, or
Low Density Parity Check (LDPC) encoder/decoder functionality.
Embodiments of modulation/demodulation and encoder/decoder
functionality are not limited to these examples and may include
other suitable functionality in other embodiments.
[0162] In some embodiments, the baseband circuitry 1204 may include
one or more audio digital signal processor(s) (DSP) 1204F. The
audio DSP(s) 1204F may be include elements for
compression/decompression and echo cancellation and may include
other suitable processing elements in other embodiments. Components
of the baseband circuitry may be suitably combined in a single
chip, a single chipset, or disposed on a same circuit board in some
embodiments. In some embodiments, some or all of the constituent
components of the baseband circuitry 1204 and the application
circuitry 1202 may be implemented together such as, for example, on
a system on a chip (SOC).
[0163] In some embodiments, the baseband circuitry 1204 may provide
for communication compatible with one or more radio technologies.
For example, in some embodiments, the baseband circuitry 1204 may
support communication with an evolved universal terrestrial radio
access network (EUTRAN) or other wireless metropolitan area
networks (WMAN), a wireless local area network (WLAN), or a
wireless personal area network (WPAN). Embodiments in which the
baseband circuitry 1204 is configured to support radio
communications of more than one wireless protocol may be referred
to as multi-mode baseband circuitry.
[0164] RF circuitry 1206 may enable communication with wireless
networks using modulated electromagnetic radiation through a
non-solid medium. In various embodiments, the RF circuitry 1206 may
include switches, filters, amplifiers, etc. to facilitate the
communication with the wireless network. The RF circuitry 1206 may
include a receive signal path which may include circuitry to
down-convert RF signals received from the FEM circuitry 1208 and
provide baseband signals to the baseband circuitry 1204. RF
circuitry 1206 may also include a transmit signal path which may
include circuitry to up-convert baseband signals provided by the
baseband circuitry 1204 and provide RF output signals to the FEM
circuitry 1208 for transmission.
[0165] In some embodiments, the receive signal path of the RF
circuitry 1206 may include mixer circuitry 1206A, amplifier
circuitry 1206B and filter circuitry 1206C. In some embodiments,
the transmit signal path of the RF circuitry 1206 may include
filter circuitry 1206C and mixer circuitry 1206A. RF circuitry 1206
may also include synthesizer circuitry 1206D for synthesizing a
frequency for use by the mixer circuitry 1206A of the receive
signal path and the transmit signal path. In some embodiments, the
mixer circuitry 1206A of the receive signal path may be configured
to down-convert RF signals received from the FEM circuitry 1208
based on the synthesized frequency provided by synthesizer
circuitry 1206D. The amplifier circuitry 1206B may be configured to
amplify the down-converted signals and the filter circuitry 1206C
may be a low-pass filter (LPF) or band-pass filter (BPF) configured
to remove unwanted signals from the down-converted signals to
generate output baseband signals. Output baseband signals may be
provided to the baseband circuitry 1204 for further processing. In
some embodiments, the output baseband signals may be zero-frequency
baseband signals, although this is not a requirement. In some
embodiments, the mixer circuitry 1206A of the receive signal path
may comprise passive mixers, although the scope of the embodiments
is not limited in this respect.
[0166] In some embodiments, the mixer circuitry 1206A of the
transmit signal path may be configured to up-convert input baseband
signals based on the synthesized frequency provided by the
synthesizer circuitry 1206D to generate RF output signals for the
FEM circuitry 1208. The baseband signals may be provided by the
baseband circuitry 1204 and may be filtered by the filter circuitry
1206C.
[0167] In some embodiments, the mixer circuitry 1206A of the
receive signal path and the mixer circuitry 1206A of the transmit
signal path may include two or more mixers and may be arranged for
quadrature downconversion and upconversion, respectively. In some
embodiments, the mixer circuitry 1206A of the receive signal path
and the mixer circuitry 1206A of the transmit signal path may
include two or more mixers and may be arranged for image rejection
(e.g., Hartley image rejection). In some embodiments, the mixer
circuitry 1206A of the receive signal path and the mixer circuitry
1206A may be arranged for direct downconversion and direct
upconversion, respectively. In some embodiments, the mixer
circuitry 1206A of the receive signal path and the mixer circuitry
1206A of the transmit signal path may be configured for
super-heterodyne operation.
[0168] In some embodiments, the output baseband signals and the
input baseband signals may be analog baseband signals, although the
scope of the embodiments is not limited in this respect. In some
alternate embodiments, the output baseband signals and the input
baseband signals may be digital baseband signals. In these
alternate embodiments, the RF circuitry 1206 may include
analog-to-digital converter (ADC) and digital-to-analog converter
(DAC) circuitry and the baseband circuitry 1204 may include a
digital baseband interface to communicate with the RF circuitry
1206.
[0169] In some dual-mode embodiments, a separate radio IC circuitry
may be provided for processing signals for each spectrum, although
the scope of the embodiments is not limited in this respect.
[0170] In some embodiments, the synthesizer circuitry 1206D may be
a fractional-N synthesizer or a fractional N/N+1 synthesizer,
although the scope of the embodiments is not limited in this
respect as other types of frequency synthesizers may be suitable.
For example, synthesizer circuitry 1206D may be a delta-sigma
synthesizer, a frequency multiplier, or a synthesizer comprising a
phase-locked loop with a frequency divider.
[0171] The synthesizer circuitry 1206D may be configured to
synthesize an output frequency for use by the mixer circuitry 1206A
of the RF circuitry 1206 based on a frequency input and a divider
control input. In some embodiments, the synthesizer circuitry 1206D
may be a fractional N/N+1 synthesizer.
[0172] In some embodiments, frequency input may be provided by a
voltage controlled oscillator (VCO), although that is not a
requirement. Divider control input may be provided by either the
baseband circuitry 1204 or the application circuitry 1202 (such as
an applications processor) depending on the desired output
frequency. In some embodiments, a divider control input (e.g., N)
may be determined from a look-up table based on a channel indicated
by the application circuitry 1202.
[0173] Synthesizer circuitry 1206D of the RF circuitry 1206 may
include a divider, a delay-locked loop (DLL), a multiplexer and a
phase accumulator. In some embodiments, the divider may be a dual
modulus divider (DMD) and the phase accumulator may be a digital
phase accumulator (DPA). In some embodiments, the DMD may be
configured to divide the input signal by either N or N+1 (e.g.,
based on a carry out) to provide a fractional division ratio. In
some example embodiments, the DLL may include a set of cascaded,
tunable, delay elements, a phase detector, a charge pump and a
D-type flip-flop. In these embodiments, the delay elements may be
configured to break a VCO period up into Nd equal packets of phase,
where Nd is the number of delay elements in the delay line. In this
way, the DLL provides negative feedback to help ensure that the
total delay through the delay line is one VCO cycle.
[0174] In some embodiments, the synthesizer circuitry 1206D may be
configured to generate a carrier frequency as the output frequency,
while in other embodiments, the output frequency may be a multiple
of the carrier frequency (e.g., twice the carrier frequency, four
times the carrier frequency) and used in conjunction with
quadrature generator and divider circuitry to generate multiple
signals at the carrier frequency with multiple different phases
with respect to each other. In some embodiments, the output
frequency may be a LO frequency (fLO). In some embodiments, the RF
circuitry 1206 may include an IQ/polar converter.
[0175] FEM circuitry 1208 may include a receive signal path which
may include circuitry configured to operate on RF signals received
from one or more antennas 1210, amplify the received signals and
provide the amplified versions of the received signals to the RF
circuitry 1206 for further processing. The FEM circuitry 1208 may
also include a transmit signal path which may include circuitry
configured to amplify signals for transmission provided by the RF
circuitry 1206 for transmission by one or more of the one or more
antennas 1210. In various embodiments, the amplification through
the transmit or receive signal paths may be done solely in the RF
circuitry 1206, solely in the FEM circuitry 1208, or in both the RF
circuitry 1206 and the FEM circuitry 1208.
[0176] In some embodiments, the FEM circuitry 1208 may include a
TX/RX switch to switch between transmit mode and receive mode
operation. The FEM circuitry 1208 may include a receive signal path
and a transmit signal path. The receive signal path of the FEM
circuitry 1208 may include an LNA to amplify received RF signals
and provide the amplified received RF signals as an output (e.g.,
to the RF circuitry 1206). The transmit signal path of the FEM
circuitry 1208 may include a power amplifier (PA) to amplify input
RF signals (e.g., provided by the RF circuitry 1206), and one or
more filters to generate RF signals for subsequent transmission
(e.g., by one or more of the one or more antennas 1210).
[0177] In some embodiments, the PMC 1212 may manage power provided
to the baseband circuitry 1204. In particular, the PMC 1212 may
control power-source selection, voltage scaling, battery charging,
or DC-to-DC conversion. The PMC 1212 may often be included when the
device 1200 is capable of being powered by a battery, for example,
when the device 1200 is included in a UE. The PMC 1212 may increase
the power conversion efficiency while providing desirable
implementation size and heat dissipation characteristics.
[0178] FIG. 12 shows the PMC 1212 coupled only with the baseband
circuitry 1204. However, in other embodiments, the PMC 1212 may be
additionally or alternatively coupled with, and perform similar
power management operations for, other components such as, but not
limited to, the application circuitry 1202, the RF circuitry 1206,
or the FEM circuitry 1208.
[0179] In some embodiments, the PMC 1212 may control, or otherwise
be part of, various power saving mechanisms of the device 1200. For
example, if the device 1200 is in an RRC_Connected state, where it
is still connected to the RAN node as it expects to receive traffic
shortly, then it may enter a state known as Discontinuous Reception
Mode (DRX) after a period of inactivity. During this state, the
device 1200 may power down for brief intervals of time and thus
save power.
[0180] If there is no data traffic activity for an extended period
of time, then the device 1200 may transition off to an RRC_Idle
state, where it disconnects from the network and does not perform
operations such as channel quality feedback, handover, etc. The
device 1200 goes into a very low power state and it performs paging
where again it periodically wakes up to listen to the network and
then powers down again. The device 1200 may not receive data in
this state, and in order to receive data, it transitions back to an
RRC_Connected state.
[0181] An additional power saving mode may allow a device to be
unavailable to the network for periods longer than a paging
interval (ranging from seconds to a few hours). During this time,
the device is totally unreachable to the network and may power down
completely. Any data sent during this time incurs a large delay and
it is assumed the delay is acceptable.
[0182] Processors of the application circuitry 1202 and processors
of the baseband circuitry 1204 may be used to execute elements of
one or more instances of a protocol stack. For example, processors
of the baseband circuitry 1204, alone or in combination, may be
used to execute Layer 3, Layer 2, or Layer 1 functionality, while
processors of the application circuitry 1202 may utilize data
(e.g., packet data) received from these layers and further execute
Layer 4 functionality (e.g., transmission communication protocol
(TCP) and user datagram protocol (UDP) layers). As referred to
herein, Layer 3 may comprise a radio resource control (RRC) layer,
described in further detail below. As referred to herein, Layer 2
may comprise a medium access control (MAC) layer, a radio link
control (RLC) layer, and a packet data convergence protocol (PDCP)
layer, described in further detail below. As referred to herein,
Layer 1 may comprise a physical (PHY) layer of a UE/RAN node,
described in further detail below.
[0183] FIG. 13 illustrates example interfaces of baseband circuitry
in accordance with some embodiments. As discussed above, the
baseband circuitry 1204 of FIG. 12 may comprise processors
1204A-1204E and a memory 1204G utilized by said processors. Each of
the processors 1204A-1204E may include a memory interface,
1304A-1304E, respectively, to send/receive data to/from the memory
1204G.
[0184] The baseband circuitry 1204 may further include one or more
interfaces to communicatively couple to other circuitries/devices,
such as a memory interface 1312 (e.g., an interface to send/receive
data to/from memory external to the baseband circuitry 1204), an
application circuitry interface 1314 (e.g., an interface to
send/receive data to/from the application circuitry 1202 of FIG.
12), an RF circuitry interface 1316 (e.g., an interface to
send/receive data to/from RF circuitry 1206 of FIG. 12), a wireless
hardware connectivity interface 1318 (e.g., an interface to
send/receive data to/from Near Field Communication (NFC)
components, Bluetooth.RTM. components (e.g., Bluetooth.RTM. Low
Energy), Wi-Fi.RTM. components, and other communication
components), and a power management interface 1320 (e.g., an
interface to send/receive power or control signals to/from the PMC
1212.
[0185] FIG. 14 is an illustration of a control plane protocol stack
in accordance with some embodiments. In this embodiment, a control
plane 1400 is shown as a communications protocol stack between the
UE 1101 (or alternatively, the UE 1102), the RAN node 1111 (or
alternatively, the RAN node 1112), and the MME 1121.
[0186] A PHY layer 1401 may transmit or receive information used by
the MAC layer 1402 over one or more air interfaces. The PHY layer
1401 may further perform link adaptation or adaptive modulation and
coding (AMC), power control, cell search (e.g., for initial
synchronization and handover purposes), and other measurements used
by higher layers, such as an RRC layer 1405. The PHY layer 1401 may
still further perform error detection on the transport channels,
forward error correction (FEC) coding/decoding of the transport
channels, modulation/demodulation of physical channels,
interleaving, rate matching, mapping onto physical channels, and
Multiple Input Multiple Output (MIMO) antenna processing.
[0187] The MAC layer 1402 may perform mapping between logical
channels and transport channels, multiplexing of MAC service data
units (SDUs) from one or more logical channels onto transport
blocks (TB) to be delivered to PHY via transport channels,
de-multiplexing MAC SDUs to one or more logical channels from
transport blocks (TB) delivered from the PHY via transport
channels, multiplexing MAC SDUs onto TBs, scheduling information
reporting, error correction through hybrid automatic repeat request
(HARQ), and logical channel prioritization.
[0188] An RLC layer 1403 may operate in a plurality of modes of
operation, including: Transparent Mode (TM), Unacknowledged Mode
(UM), and Acknowledged Mode (AM). The RLC layer 1403 may execute
transfer of upper layer protocol data units (PDUs), error
correction through automatic repeat request (ARQ) for AM data
transfers, and concatenation, segmentation and reassembly of RLC
SDUs for UM and AM data transfers. The RLC layer 1403 may also
execute re-segmentation of RLC data PDUs for AM data transfers,
reorder RLC data PDUs for UM and AM data transfers, detect
duplicate data for UM and AM data transfers, discard RLC SDUs for
UM and AM data transfers, detect protocol errors for AM data
transfers, and perform RLC re-establishment.
[0189] A PDCP layer 1404 may execute header compression and
decompression of IP data, maintain PDCP Sequence Numbers (SNs),
perform in-sequence delivery of upper layer PDUs at
re-establishment of lower layers, eliminate duplicates of lower
layer SDUs at re-establishment of lower layers for radio bearers
mapped on RLC AM, cipher and decipher control plane data, perform
integrity protection and integrity verification of control plane
data, control timer-based discard of data, and perform security
operations (e.g., ciphering, deciphering, integrity protection,
integrity verification, etc.).
[0190] The main services and functions of the RRC layer 1405 may
include broadcast of system information (e.g., included in Master
Information Blocks (MIBs) or System Information Blocks (SIBs)
related to the non-access stratum (NAS)), broadcast of system
information related to the access stratum (AS), paging,
establishment, maintenance and release of an RRC connection between
the UE and E-UTRAN (e.g., RRC connection paging, RRC connection
establishment, RRC connection modification, and RRC connection
release), establishment, configuration, maintenance and release of
point-to-point radio bearers, security functions including key
management, inter radio access technology (RAT) mobility, and
measurement configuration for UE measurement reporting. Said MIBs
and SIBs may comprise one or more information elements (IEs), which
may each comprise individual data fields or data structures.
[0191] The UE 1101 and the RAN node 1111 may utilize a Uu interface
(e.g., an LTE-Uu interface) to exchange control plane data via a
protocol stack comprising the PHY layer 1401, the MAC layer 1402,
the RLC layer 1403, the PDCP layer 1404, and the RRC layer
1405.
[0192] In the embodiment shown, the non-access stratum (NAS)
protocols 1406 form the highest stratum of the control plane
between the UE 1101 and the MME 1121. The NAS protocols 1406
support the mobility of the UE 1101 and the session management
procedures to establish and maintain IP connectivity between the UE
1101 and the P-GW 1123.
[0193] The S1 Application Protocol (S1-AP) layer 1415 may support
the functions of the S1 interface and comprise Elementary
Procedures (EPs). An EP is a unit of interaction between the RAN
node 1111 and the CN 1120. The S1-AP layer services may comprise
two groups: UE-associated services and non UE-associated services.
These services perform functions including, but not limited to:
E-UTRAN Radio Access Bearer (E-RAB) management, UE capability
indication, mobility, NAS signaling transport, RAN Information
Management (RIM), and configuration transfer.
[0194] The Stream Control Transmission Protocol (SCTP) layer
(alternatively referred to as the stream control transmission
protocol/internet protocol (SCTP/IP) layer) 1414 may ensure
reliable delivery of signaling messages between the RAN node 1111
and the MME 1121 based, in part, on the IP protocol, supported by
an IP layer 1413. An L2 layer 1412 and an L1 layer 1411 may refer
to communication links (e.g., wired or wireless) used by the RAN
node and the MME to exchange information.
[0195] The RAN node 1111 and the MME 1121 may utilize an S1-MME
interface to exchange control plane data via a protocol stack
comprising the L1 layer 1411, the L2 layer 1412, the IP layer 1413,
the SCTP layer 1414, and the S1-AP layer 1415.
[0196] FIG. 15 illustrates components of a core network in
accordance with some embodiments. The components of the CN 1120 may
be implemented in one physical node or separate physical nodes
including components to read and execute instructions from a
machine-readable or computer-readable medium (e.g., a
non-transitory machine-readable storage medium). In some
embodiments, Network Functions Virtualization (NFV) is utilized to
virtualize any or all of the above described network node functions
via executable instructions stored in one or more computer readable
storage mediums (described in further detail below). A logical
instantiation of the CN 1120 may be referred to as a network slice
1501. A logical instantiation of a portion of the CN 1120 may be
referred to as a network sub-slice 1502 (e.g., the network
sub-slice 1502 is shown to include the PGW 1123 and the PCRF
1126).
[0197] NFV architectures and infrastructures may be used to
virtualize one or more network functions, alternatively performed
by proprietary hardware, onto physical resources comprising a
combination of industry-standard server hardware, storage hardware,
or switches. In other words, NFV systems can be used to execute
virtual or reconfigurable implementations of one or more EPC
components/functions.
[0198] FIG. 16 is a block diagram illustrating components,
according to some example embodiments, able to read instructions
from a machine-readable or computer-readable medium (e.g., a
non-transitory machine-readable storage medium) and perform any one
or more of the methodologies discussed herein. Specifically, FIG.
16 shows a diagrammatic representation of hardware resources 1600
including one or more processors (or processor cores) 1610, one or
more memory/storage devices 1620, and one or more communication
resources 1630, each of which may be communicatively coupled via a
bus 1640. For embodiments where node virtualization (e.g., NFV) is
utilized, a hypervisor 1602 may be executed to provide an execution
environment for one or more network slices/sub-slices to utilize
the hardware resources 1600.
[0199] The processors 1610 (e.g., a central processing unit (CPU),
a reduced instruction set computing (RISC) processor, a complex
instruction set computing (CISC) processor, a graphics processing
unit (GPU), a digital signal processor (DSP) such as a baseband
processor, an application specific integrated circuit (ASIC), a
radio-frequency integrated circuit (RFIC), another processor, or
any suitable combination thereof) may include, for example, a
processor 1612 and a processor 1614.
[0200] The memory/storage devices 1620 may include main memory,
disk storage, or any suitable combination thereof. The
memory/storage devices 1620 may include, but are not limited to,
any type of volatile or non-volatile memory such as dynamic random
access memory (DRAM), static random-access memory (SRAM), erasable
programmable read-only memory (EPROM), electrically erasable
programmable read-only memory (EEPROM), Flash memory, solid-state
storage, etc.
[0201] The communication resources 1630 may include interconnection
or network interface components or other suitable devices to
communicate with one or more peripheral devices 1604 or one or more
databases 1606 via a network 1608. For example, the communication
resources 1630 may include wired communication components (e.g.,
for coupling via a Universal Serial Bus (USB)), cellular
communication components, NFC components, Bluetooth.RTM. components
(e.g., Bluetooth.RTM. Low Energy), Wi-Fi.RTM. components, and other
communication components.
[0202] Instructions 1650 may comprise software, a program, an
application, an applet, an app, or other executable code for
causing at least any of the processors 1610 to perform any one or
more of the methodologies discussed herein. The instructions 1650
may reside, completely or partially, within at least one of the
processors 1610 (e.g., within the processor's cache memory), the
memory/storage devices 1620, or any suitable combination thereof.
Furthermore, any portion of the instructions 1650 may be
transferred to the hardware resources 1600 from any combination of
the peripheral devices 1604 or the databases 1606. Accordingly, the
memory of processors 1610, the memory/storage devices 1620, the
peripheral devices 1604, and the databases 1606 are examples of
computer-readable and machine-readable media.
[0203] FIG. 17 is a simplified flowchart illustrating a method 1700
of operating a wireless communication node (e.g., a receive node),
according to some embodiments. In some embodiments, the device of
FIGS. 12 and 16, and particularly the baseband circuitry of FIG.
13, may be configured to identify 1710 or cause to identify a
received channel state information-reference signal (CSI-RS) from a
Transmit/Receive Point (TRP). The device may be further configured
to determine 1720 or cause to determine a response signal based
upon the received CSI-RS signal. The device may be further
configured to transmit 1730 or cause to transmit the response
signal.
[0204] FIG. 18 is a simplified flowchart illustrating a method 1800
of operating a wireless communication device (e.g., a transmit
node), according to some embodiments. In embodiments, the device
may be configured to transmit 1810 or cause to transmit a sequence
of reference signals (RS) from a plurality of antenna ports to a
user equipment (UE). The device may be further configured to
identify 1820 or cause to identify a received response signal from
the UE. The device may be further to, based upon the received
response signal, determine 1830 or cause to determine an estimated
scheduling utility function. The device may be further configured
to transmit 1840 or cause to transmit a demodulation reference
signal (DMRS) to the UE.
[0205] In some embodiments, the electronic device(s), network(s),
system(s), chip(s) or component(s), or portions or implementations
thereof, of FIGS. 12, 13, 14, 15, 16, or some other figure herein
may be configured to perform one or more processes, techniques, or
methods as described herein, or portions thereof. One such process
is depicted in FIG. 17, as discussed above.
[0206] In some embodiments, the electronic device(s), network(s),
system(s), chip(s) or component(s), or portions or implementations
thereof, of FIG. 12, 13, 14, 15, 16, or some other figure herein
may be configured to perform one or more processes, techniques, or
methods as described herein, or portions thereof. One such process
is depicted in FIG. 18, as discussed above.
EXAMPLES
[0207] The following is a non-exhaustive list of example
embodiments that fall within the scope of the disclosure. In order
to avoid complexity in providing the disclosure, not all of the
examples listed below are separately and explicitly disclosed as
having been contemplated herein as combinable with all of the
others of the examples listed below and other embodiments disclosed
hereinabove. Unless one of ordinary skill in the art would
understand that these examples listed below, and the above
disclosed embodiments, are not combinable, it is contemplated
within the scope of the disclosure that such examples and
embodiments are combinable.
[0208] Example 1 may include a user equipment (UE) apparatus
comprising: means for identifying or causing to identify a received
channel state information-reference signal (CSI-RS) from a
Transmit/Receive Point (TRP); means for determining or causing to
determine a response signal based upon the received CSI-RS signal;
and means for transmitting or causing to transmit the response
signal.
[0209] Example 2 may include the subject matter of example 1, or of
any other example herein, further including means for identifying
or causing to identify a second received signal.
[0210] Example 3 may include the subject matter of example 1, or of
any other example herein, wherein the means for determining or
causing to determine the response signal further includes means for
quantizing or causing to quantize the received CSI-RS signal
without performing preprocessing, means for quantizing or causing
to quantize the received CSI-RS signal with performing
preprocessing, or means for quantizing or causing to quantize a
subset of the received signal.
[0211] Example 4 may include the subject matter of example 3, or of
any other example herein, wherein the response signal further
includes uplink reference signals to enable the TRP to measure an
uplink channel to facilitate received signal equalization by the
TRP.
[0212] Example 5 may include the subject matter of example 1, or of
any other example herein, wherein the means for transmitting or
causing to transmit further includes means for transmitting or
causing to transmit using multiple antennas.
[0213] Example 6 may include the subject matter of example 5, or of
any other example herein, wherein the means for transmitting or
causing to transmit further includes means for identifying or
causing to identify a received beamforming vector prior to
transmission.
[0214] Example 7 may include the subject matter of example 2, or of
any other example herein, wherein the means for identifying or
causing to identify a second receive signal further includes means
for decoding or causing to decode a demodulation reference signal
(DMRS), or means for decoding or causing to decode data.
[0215] Example 8 may include a Transmit/Receive Point (TRP)
apparatus comprising: means for transmitting or causing to transmit
a sequence of reference signals (RS) from a plurality of antenna
ports to a user equipment (UE); means for identifying or causing to
identify a received response signal from the DE; means for
determining or causing to determine an estimated scheduling utility
function based upon the received response signal; and means for
transmitting or causing to transmit a demodulation reference signal
(DMRS) to the DE.
[0216] Example 9 may include the subject matter of example 8, or of
any other example herein, wherein the means for transmitting or
causing to transmit the sequence of RS from a plurality of antenna
ports is further for transmitting or causing to transmit a sequence
of RS from a plurality of antenna ports simultaneously.
[0217] Example 10 may include the subject matter of example 8, or
of any other example herein, wherein the means for transmitting or
causing to transmit the sequence of RS is further for transmitting
or causing to transmit a precoded channel state information
(CSI)-RS.
[0218] Example 11 may include the subject matter of example 8, or
of any other example herein, wherein the received response signal
includes quantized DE-received RS based upon the transmitted
sequence of RS.
[0219] Example 12 may include the subject matter of example 11, or
of any other example herein, wherein quantized DE-received RS
includes partially quantized DE-received RS.
[0220] Example 13 may include the subject matter of example 8, or
of any other example herein, wherein the means for transmitting or
causing to transmit a sequence of RS is further for transmitting or
causing to transmit data streams.
[0221] Example 14 may include the subject matter of example 13, or
of any other example herein, wherein the means for transmitting or
causing to transmit a sequence of RS is further for transmitting or
causing to transmit a sequence of RS using a first codebook.
[0222] Example 15 may include the subject matter of example 13, or
of any other example herein, wherein the means for transmitting or
causing to transmit data streams is further for transmitting or
causing to transmit data streams using a second codebook.
[0223] Example 16 may include the subject matter of examples 13-15,
or of any other example herein, wherein the first codebook and the
second codebook are a same codebook.
[0224] Example 17 may include the subject matter of examples 13-15,
or of any other example herein, further including means for
uploading or causing to upload the first codebook and/or the second
codebook to the TRP.
[0225] Example 18 may include the subject matter of example 8, or
of any other example herein, wherein means for determining or
causing to determine an estimated scheduling utility function is
further for determining or causing to determine an estimated
scheduling utility function based upon
signal-to-noise-plus-interference ratio (SINR), leakage
interference power, background information, convex optimization,
and/or learning algorithms.
[0226] Example 19 may include the subject matter of example 8, or
of any other example herein, wherein the estimated scheduling
utility function is optimized over different sets of
parameters.
[0227] Example 20 may include the subject matter of example 8, or
of any other example herein, wherein means for transmitting or
causing to transmit is further for transmitting or causing to
transmit using beamforming.
[0228] Example 21 may include a TRP equipped with multiple antenna
ports and two codebooks. A first codebook is used to transmit
precoded RS and a second codebook is used to precode data streams
such that multiple data streams on the same resource element do not
interfere.
[0229] Example 22 may include the subject matter of example 21 or
some other example herein, where the same codebooks are used to
transmit RS and data.
[0230] Example 23 may include the subject matter of example 21 or
some other example herein, where codebooks are loaded/updated if
the wireless propagation environment changes.
[0231] Example 24 may include a UE equipped with a single antenna
that quantizes the received RS and feeds them back to the TRP
without performing any preprocessing of the received signal.
[0232] Example 25 may include the subject matter of example 24 or
some other example herein, where the UE performs some preprocessing
of the received signal.
[0233] Example 26 may include the subject matter of example 24 or
some other example herein, where only a subset of RSs are quantized
and fed back.
[0234] Example 27 may include the subject matter of example 24 or
some other example herein, where the UE is equipped with multiple
antennas and fixes a receive beamforming vector beforehand.
[0235] Example 28 may include the subject matter of example 24 or
some other example herein, where the UE performs no quantization
but relays the received signal back to the TRP along with some
uplink reference signals which enable the TRP to measure the uplink
channel such that the TRP can equalize the received signal.
[0236] Example 29 may include the subject matter of example 24 or
some other example herein, where one additional bit is fed back to
signal that the measurement codebook needs to be updated by the
TRP.
[0237] Example 30 may include the method for resource allocation in
a wireless network comprising of one or more TRPs and one or more
UEs. The method uses feedback information from the UE to estimate a
utility function for different transmit parameter sets.
[0238] Example 31 may include the subject matter of example 30 or
some other example herein, with an algorithm that optimizes the
estimated utility function over different sets of parameters.
[0239] Example 32 may include the subject matter from example 30 or
some other example herein, where the TRP uses additional side
information like statistical information about the wireless
channels to estimate the network utility function.
[0240] Example 33 may include a user equipment (UE) apparatus to:
identify or cause to identify a received channel state
information-reference signal (CSI-RS) from a Transmit/Receive Point
(TRP); determine or cause to determine a response signal based upon
the received CSI-RS signal; and transmit or cause to transmit the
response signal.
[0241] Example 34 may include the subject matter of example 33, or
of any other example herein, further including identify or cause to
identify a second received signal.
[0242] Example 35 may include the subject matter of example 33, or
of any other example herein, wherein determine or cause to
determine the response signal further includes quantize or cause to
quantize the received CSI-RS signal without performing
preprocessing, quantize or cause to quantize the received CSI-RS
signal with performing preprocessing, and quantize or cause to
quantize a subset of the received signal.
[0243] Example 36 may include the subject matter of example 35, or
of any other example herein, wherein the response signal further
includes uplink reference signals to enable the TRP to measure an
uplink channel to facilitate received signal equalization by the
TRP.
[0244] Example 37 may include the subject matter of example 33, or
of any other example herein, wherein transmit or cause to transmit
further includes transmit or cause to transmit using multiple
antennas.
[0245] Example 38 may include the subject matter of example 37, or
of any other example herein, wherein transmit or cause to transmit
further includes identify or cause to identify a received
beamforming vector prior to transmission.
[0246] Example 39 may include the subject matter of example 34, or
of any other example herein, wherein identify or cause to identify
a second receive signal further includes decode or cause to decode
a demodulation reference signal (DMRS), or decode or cause to
decode data.
[0247] Example 40 may include Transmit/Receive point (TRP)
apparatus to: transmit or cause to transmit a sequence of reference
signals (RS) from a plurality of antenna ports to a user equipment
(UE); identify or cause to identify a received response signal from
the UE; determine or cause to determine an estimated scheduling
utility function based upon the received response signal; and
transmit or cause to transmit a demodulation reference signal
(DMRS) to the UE.
[0248] Example 41 may include the subject matter of example 40, or
of any other example herein, wherein transmit or cause to transmit
a sequence of RS from a plurality of antenna ports further includes
transmit or cause to transmit a sequence of RS from a plurality of
antenna ports simultaneously.
[0249] Example 42 may include the subject matter of example 40, or
of any other example herein, wherein transmit or cause to transmit
the sequence of RS further includes transmit or cause to transmit a
precoded channel state information (CSI)-RS.
[0250] Example 43 may include the subject matter of example 40, or
of any other example herein, wherein the received response signal
includes quantized UE-received RS based upon the transmitted
sequence of RS.
[0251] Example 44 may include the subject matter of example 43, or
of any other example herein, wherein quantized DE-received RS
includes partially quantized UE-received RS.
[0252] Example 45 may include the subject matter of example 40, or
of any other example herein, wherein transmit or cause to transmit
a sequence of RS further includes transmit or cause to transmit
data streams.
[0253] Example 46 may include the subject matter of example 45, or
of any other example herein, wherein transmit or cause to transmit
a sequence of RS further includes transmit or cause to transmit a
sequence of RS using a first codebook.
[0254] Example 47 may include the subject matter of example 45, or
of any other example herein, wherein transmit or cause to transmit
data streams further includes transmit or cause to transmit data
streams using a second codebook.
[0255] Example 48 may include the subject matter of examples 45-47,
or of any other example herein, wherein the first codebook and the
second codebook are a same codebook.
[0256] Example 49 may include the subject matter of examples 45-47,
or of any other example herein, further including uploading or
causing to upload the first codebook and/or the second codebook to
the TRP.
[0257] Example 50 may include the subject matter of example 40, or
of any other example herein, determining or causing to determine an
estimated scheduling utility function, and further includes
determining or causing to determine an estimated scheduling utility
function based upon signal-to-noise-plus-interference ratio (SINR),
leakage interference power, background information, convex
optimization, and/or learning algorithms.
[0258] Example 51 may include the subject matter of example 40, or
of any other example herein, wherein the estimated scheduling
utility function is optimized over different sets of
parameters.
[0259] Example 52 may include the subject matter of example 40, or
of any other example herein, wherein transmitting or causing to
transmit further includes transmitting or causing to transmit using
beamforming.
[0260] Example 53 may include a method for implementing a user
equipment (UE) comprising: identifying or causing to identify a
received channel state information-reference signal (CSI-RS) from a
Transmit/Receive Point (TRP); determining or causing to determine a
response signal based upon the received CSI-RS signal; and
transmitting or causing to transmit the response signal.
[0261] Example 54 may include the subject matter of example 53, or
of any other example herein, further including identifying or
causing to identify a second received signal.
[0262] Example 55 may include the subject matter of example 53, or
of any other example herein, wherein determining or causing to
determine the response signal further includes quantizing or
causing to quantize the received CSI-RS signal without performing
preprocessing, quantizing or causing to quantize the received
CSI-RS signal with performing preprocessing, or quantizing or
causing to quantize a subset of the received signal.
[0263] Example 56 may include the subject matter of example 55, or
of any other example herein, wherein the response signal further
includes uplink reference signals to enable the TRP to measure an
uplink channel to facilitate received signal equalization by the
TRP.
[0264] Example 57 may include the subject matter of example 53, or
of any other example herein, wherein transmitting or causing to
transmit further includes transmitting or causing to transmit using
multiple antennas.
[0265] Example 58 may include the subject matter of example 57, or
of any other example herein, wherein transmitting or causing to
transmit further includes identifying or causing to identify a
received beamforming vector prior to transmission.
[0266] Example 59 may include the subject matter of example 54, or
of any other example herein, wherein identifying or causing to
identify a second receive signal further includes decoding or
causing to decode a demodulation reference signal (DMRS), or
decoding or causing to decode data.
[0267] Example 60 may include a method for implementing
Transmit/Receive point (TRP) comprising: transmitting or causing to
transmit a sequence of reference signals (RS) from a plurality of
antenna ports to a user equipment (UE); identifying or causing to
identify a received response signal from the UE; based upon the
received response signal, determining or causing to determine an
estimated scheduling utility function; and transmitting or causing
to transmit a demodulation reference signal (DMRS) to the UE.
[0268] Example 61 may include the subject matter of example 60, or
of any other example herein, wherein transmitting or causing to
transmit a sequence of RS from a plurality of antenna ports further
includes transmitting or causing to transmit a sequence of RS from
a plurality of antenna ports simultaneously.
[0269] Example 62 may include the subject matter of example 60, or
of any other example herein, wherein transmitting or causing to
transmit the sequence of RS further includes transmitting or
causing to transmit a precoded channel state information
(CSI)-RS.
[0270] Example 63 may include the subject matter of example 60, or
of any other example herein, wherein the received response signal
includes quantized DE-received RS based upon the transmitted
sequence of RS.
[0271] Example 64 may include the subject matter of example 63, or
of any other example herein, wherein quantized DE-received RS
includes partially quantized DE-received RS.
[0272] Example 65 may include the subject matter of example 60, or
of any other example herein, wherein transmitting or causing to
transmit a sequence of RS further includes transmitting or causing
to transmit data streams.
[0273] Example 66 may include the subject matter of example 65, or
of any other example herein, wherein transmitting or causing to
transmit a sequence of RS further includes transmitting or causing
to transmit a sequence of RS using a first codebook.
[0274] Example 67 may include the subject matter of example 65, or
of any other example herein, wherein transmitting or causing to
transmit data streams further includes transmitting or causing to
transmit data streams using a second codebook.
[0275] Example 68 may include the subject matter of examples 65-67,
or of any other example herein, wherein the first codebook and the
second codebook are a same codebook.
[0276] Example 69 may include the subject matter of examples 65-67,
or of any other example herein, further including uploading or
causing to upload the first codebook and/or the second codebook to
the TRP.
[0277] Example 70 may include the subject matter of example 60, or
of any other example herein, determining or causing to determine an
estimated scheduling utility function further includes determining
or causing to determine an estimated scheduling utility function
based upon signal-to-noise-plus-interference ratio (SINR), leakage
interference power, background information, convex optimization,
and/or learning algorithms.
[0278] Example 71 may include the subject matter of example 60, or
of any other example herein, wherein the estimated scheduling
utility function is optimized over different sets of
parameters.
[0279] Example 72 may include the subject matter of example 60, or
of any other example herein, wherein transmitting or causing to
transmit further includes transmitting or causing to transmit using
beamforming.
[0280] Example 73 may include an apparatus comprising means to
perform one or more elements of a method described in or related to
any of examples 1-72, or any other method or process described
herein.
[0281] Example 74 may include one or more non-transitory
computer-readable media comprising instructions to cause an
electronic device, upon execution of the instructions by one or
more processors of the electronic device, to perform one or more
elements of a method described in or related to any of examples
1-72, or any other method or process described herein.
[0282] Example 75 may include an apparatus comprising logic,
modules, or circuitry to perform one or more elements of a method
described in or related to any of examples 1-72, or any other
method or process described herein.
[0283] Example 76 may include a method, technique, or process as
described in or related to any of examples 1-72, or portions or
parts thereof.
[0284] Example 77 may include an apparatus comprising: one or more
processors and one or more computer readable media comprising
instructions that, when executed by the one or more processors,
cause the one or more processors to perform the method, techniques,
or process as described in or related to any of examples 1-72, or
portions thereof.
[0285] Example 78 may include a method of communicating in a
wireless network as shown and described herein.
[0286] Example 79 may include a system for providing wireless
communication as shown and described herein.
[0287] Example 80 may include a device for providing wireless
communication as shown and described herein.
Example 81
[0288] An apparatus of a wireless communication device, comprising:
circuitry (e.g., radio frequency circuitry) configured to measure
reference signals received from a plurality of antennas of an other
wireless communication device; and circuitry (e.g., processing
circuitry) configured to cause one or more antennas of the wireless
communication device to transmit information regarding the received
reference signals back to the other wireless communication device
to enable the other wireless communication device to estimate a
utility function for different transmit parameter sets.
Example 82
[0289] The apparatus of Example 81, wherein the circuitry
configured to cause the one or more antennas of the wireless
communication device to transmit the information regarding the
received reference signals is further configured to perform some
pre-processing of the reference signals to reduce processing at the
other wireless communication device to estimate the utility
function.
Example 83
[0290] The apparatus of Example 81, wherein the circuitry
configured to cause the one or more antennas of the wireless
communication device to transmit the information regarding the
received reference signals is further configured to quantize the
reference signals, and the information regarding the received
reference signals comprises data indicating the quantized reference
signals.
[0291] Example 84: wherein the one or more antennas of the wireless
communication device comprise multiple antennas and the circuitry
configured to cause the one or more antennas of the wireless
communication device to transmit the information regarding the
received reference signals is further configured to fix a receive
beamforming vector before the reference signals are received.
Example 85
[0292] The apparatus of Example 81, wherein the information
regarding the received reference signals comprises the reference
signals themselves that have not been quantized by the circuitry
configured to cause the one or more antennas of the wireless
communication device to transmit the information regarding the
received reference signals.
Example 86
[0293] The apparatus according to any one of Examples 81-85,
wherein the circuitry configured to cause the one or more antennas
of the wireless communication device to transmit the information
regarding the received reference signals is further configured to
generate other reference signals and control the the one or more
antennas to transmit the other reference signals to the other
wireless communication device to enable the other wireless
communication device to measure the uplink channel.
Example 87
[0294] The apparatus according to any one of Examples 81-85,
wherein the circuitry configured to cause the one or more antennas
of the wireless communication device to transmit the information
regarding the received reference signals is further configured to
determine whether a codebook used to generate the reference signals
at the other wireless communication device should be updated, and
control the radio frequency circuitry and the one or more antennas
to indicate to the other wireless communication device that the
codebook should be updated.
Example 88
[0295] The apparatus according to any one of Examples 81-85,
wherein the wireless communication device includes a user equipment
(UE) and the other wireless communication device includes a
cellular base station.
Example 89
[0296] An apparatus of a cellular base station, comprising: a data
storage device configured to store data corresponding to a first
codebook and a second codebook, the first codebook different from
the second codebook; and one or more processors configured to:
precode reference signals to be transmitted to a user equipment
(UE); and precode, using the second codebook, data streams on a
common resource element to prevent the data streams from
interfering with each other.
Example 90
[0297] The apparatus of Example 89, wherein one or more of the
first codebook or the second codebook is updated or replaced with a
different codebook responsive to: a determination that a wireless
propagation environment between the cellular base station and the
UE has changed; or an indication by the UE that the wireless
propagation environment has changed.
Example 91
[0298] An apparatus of a Radio Access Network (RAN) node,
comprising: a data storage device configured to store data
corresponding to feedback information received from a UE; and
processing circuitry configured to: estimate a utility function for
different transmit parameter sets based on the feedback information
received from the UE; and generate reference signals to be
transmitted to the UE, the feedback information indicating
information regarding measured signals measured by the UE
responsive to transmission of the reference signals to the UE.
Example 92
[0299] The apparatus of Example 91, wherein the processing
circuitry is configured to use a first codebook to precode the
reference signals and a second codebook to precode data streams to
be transmitted to the UE.
Example 93
[0300] The apparatus of Example 92, wherein the first codebook is
the same as the second codebook.
Example 94
[0301] The apparatus according to any one of Examples 91-93,
wherein the processing circuitry is configured to optimize the
estimated utility function for the different transmit parameter
sets.
Example 95
[0302] The apparatus according to any one of Examples 91-93,
wherein the processing circuitry is configured to take into
consideration statistical information about a wireless channel to
estimate the utility function.
Example 96
[0303] An apparatus of a user equipment (UE), comprising: a data
storage device configured to store a first beamforming codebook and
a second beamforming codebook that is different from the first
beamforming codebook; and processing circuitry configured to: use
the first beamforming codebook to reduce or compress dimensions of
a receive beam space of a plurality of antennas of the UE; and use
the second beamforming codebook to filter data bearing signals
received from a cellular base station.
Example 97
[0304] The apparatus of Example 96, wherein the processing
circuitry is configured to transition to use a third beamforming
codebook instead of one or more of the first beamforming codebook
or the second beamforming codebook responsive to a change in a
signal propagation environment.
Example 98
[0305] The apparatus of Example 96, wherein the one or more
processors are configured to generate a message to be transmitted
to a cellular base station, the message configured to indicate a
number of reference signals that are to be transmitted by the
cellular base station.
Example 99
[0306] The apparatus of Example 98, wherein the processing
circuitry is configured to generate the message to be transmitted
to multiple cellular base stations.
Example 100
[0307] The apparatus according to any one of Example 96-99, wherein
the processing circuitry is configured to: estimate an effective
channel gain for one or more beam pairs; and generate a message to
be transmitted to a cellular base station, the message indicating
the estimated effective channel gain.
Example 101
[0308] The apparatus according to any one of Examples 96-99,
wherein the processing circuitry is configured to determine an
optimal receive beam from the second beamforming codebook based on
measurements of reference signals received from a cellular base
station while using the first beamforming codebook.
Example 102
[0309] An apparatus of a user equipment (UE), comprising: a data
storage device configured to store sample data indicating
information measured from a uniformly sampled receive beam space;
and one or more processors configured to: estimate one or more
parameters of a plurality of receive beams of a codebook based on
the stored samples; select a receive beam from a codebook based on
the estimated one or more parameters; and receive data from a
cellular base station using the selected receive beam.
Example 103
[0310] The apparatus of Example 102, wherein the one or more
processors are configured to generate an acknowledgement (ACK)
message to be transmitted to the cellular base station, the ACK
message indicating that a quality of samples of the uniformly
sampled receive beam space is sufficient.
Example 104
[0311] The apparatus of Example 103, wherein the one or more
processors are configured to classify some of the samples of the
uniformly sampled receive beam space as useful and others of the
samples of the uniformly sampled receive beam space as not
useful.
Example 105
[0312] The apparatus according to any one of Examples 102-104,
wherein the one or more parameters used to select the receive beam
from the codebook are determined by defining a function that
depends on the sample data and a potential receive beam, the
function chosen to approximate an effective channel gain.
[0313] It will be apparent to those having skill in the art that
many changes may be made to the details of the above-described
embodiments without departing from the underlying principles of the
disclosure. The scope of the present disclosure should, therefore,
be determined only by the following claims.
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