U.S. patent application number 12/876863 was filed with the patent office on 2010-12-30 for method and apparatus for interference management in a wireless communication system.
This patent application is currently assigned to QUALCOMM INCORPORATED. Invention is credited to Jaber M. Borran, Tingfang Ji, Aamod D. Khandekar, Ritesh K. Madan, Ashwin Sampath.
Application Number | 20100329113 12/876863 |
Document ID | / |
Family ID | 42540330 |
Filed Date | 2010-12-30 |
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United States Patent
Application |
20100329113 |
Kind Code |
A1 |
Madan; Ritesh K. ; et
al. |
December 30, 2010 |
METHOD AND APPARATUS FOR INTERFERENCE MANAGEMENT IN A WIRELESS
COMMUNICATION SYSTEM
Abstract
Systems and methodologies are described herein that facilitate
interference control and resource management in a wireless
communication system. As described herein, a base station,
terminal, and/or other entity in a wireless communication system
that observes interference from one or more other network entities
can construct and communicate resource utilization messages (RUMs)
in order to request the interfering network entities to conduct
power backoff on designated resources. Parameters constructed as a
function of quality of service (QoS) and/or priority metrics (such
as head-of-line delays, queue lengths, burst sizes, delay targets,
average rates, or the like) can be included within the RUM, such
that an entity receiving the RUM can compute QoS changes associated
with various power backoff levels in order to select a power
backoff level that maximizes overall system QoS performance.
Inventors: |
Madan; Ritesh K.; (Jersey
City, NJ) ; Borran; Jaber M.; (San Diego, CA)
; Khandekar; Aamod D.; (San Diego, CA) ; Ji;
Tingfang; (San Diego, CA) ; Sampath; Ashwin;
(Skillman, NJ) |
Correspondence
Address: |
QUALCOMM INCORPORATED
5775 MOREHOUSE DR.
SAN DIEGO
CA
92121
US
|
Assignee: |
QUALCOMM INCORPORATED
San Diego
CA
|
Family ID: |
42540330 |
Appl. No.: |
12/876863 |
Filed: |
September 7, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12698349 |
Feb 2, 2010 |
|
|
|
12876863 |
|
|
|
|
61149601 |
Feb 3, 2009 |
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Current U.S.
Class: |
370/230 ;
370/252; 370/329 |
Current CPC
Class: |
H04L 5/0048 20130101;
H04W 52/243 20130101; H04W 52/26 20130101; H04L 25/0228 20130101;
H04L 5/0064 20130101; H04W 52/34 20130101; H04L 5/0007 20130101;
H04L 5/0037 20130101; H04L 5/0062 20130101; H04L 5/0023 20130101;
H04L 5/0087 20130101; H04L 5/0094 20130101; H04L 5/0067 20130101;
H04W 72/0426 20130101; H04L 5/006 20130101; H04W 72/08 20130101;
H04L 5/0075 20130101; H04L 5/0085 20130101 |
Class at
Publication: |
370/230 ;
370/252; 370/329 |
International
Class: |
H04W 72/08 20090101
H04W072/08; H04W 24/00 20090101 H04W024/00 |
Claims
1. A method for facilitating interference management on a downlink
of a wireless communication system, the method comprising:
determining, by a base station in a first cell, a benefit to a
first user equipment to which a transmission can be scheduled, the
first user equipment being in the first cell; determining, by the
base station, a degradation to a second user equipment in a second
cell, the degradation being associated with the transmission and
the second cell being different from the first cell; comparing the
benefit to the degradation; and determining, by the base station,
transmission attributes based at least on the comparison of the
benefit to the degradation, the transmission attributes including
at least one of transmit power, resource selection, precoding
matrix and beamforming vector.
2. The method of claim 1, wherein the transmission attributes are
determined in response to the degradation to the second user
equipment being greater than the benefit to the first user
equipment.
3. A computer program product, comprising: a computer-readable
medium, comprising: a first set of codes for causing a computer to
determine a benefit to a first user equipment to which a
transmission can be scheduled, the first user equipment being in a
first cell; a second set of codes for causing the computer to
determine a degradation to a second user equipment in a second
cell, the degradation being associated with the transmission, the
second cell being different from the first cell; a third set of
codes for causing the computer to compare the benefit to the
degradation; and a fourth set of codes for causing the computer to
determine transmission attributes based at least on the comparison
of the benefit to the degradation, the transmission attributes
including at least one of transmit power, resource selection,
precoding matrix and beamforming vector.
4. The computer program product of claim 3, wherein the
transmission attributes are determined in response to the
degradation to the second user equipment being greater than the
benefit to the first user equipment.
5. An apparatus, comprising: means for determining a benefit to a
benefit to a first user equipment to which a transmission can be
scheduled, the first user equipment being in the first cell; means
for determining a degradation to a second user equipment in a
second cell, the degradation being associated with the transmission
and the second cell being different from the first cell; means for
comparing the benefit to the degradation; and means for determining
transmission attributes based at least on the comparison of the
benefit to the degradation, the transmission attributes including
at least one of transmit power, resource selection, precoding
matrix and beamforming vector.
6. The apparatus of claim 5, wherein the transmission attributes
are determined in response to the degradation to the second user
equipment being greater than the benefit to the first user
equipment.
7. An apparatus, comprising: a resource coordination module
configured to: determine a benefit to a first user equipment to
which a transmission can be scheduled, the first user equipment
being in the first cell; determine a degradation to a second user
equipment in a second cell, the degradation being associated with
the transmission and the second cell being different from the first
cell; compare the benefit to the degradation; and determine
transmission attributes, wherein the transmission attributes based
at least on the comparison of the benefit to the degradation, the
transmission attributes including at least one of transmit power,
resource selection, precoding matrix and beamforming vector.
8. The apparatus of claim 7, wherein the transmission attributes
are determined in response to the degradation to the second user
equipment being greater than the benefit to the first user
equipment.
9. A method for facilitating interference management on a downlink
of a wireless communication system, the method comprising:
computing, by a base station within a cell, a total benefit to a
user equipment within the cell and to one or more out-of-cell user
equipment for one or more different transmission attributes; and
selecting, by the base station, at least one of the one or more
different transmission attributes that optimizes the total benefit
to the user equipment within the cell and to the one or more
out-of-cell user equipment.
10. A computer program product, comprising: a computer-readable
medium, comprising: a first set of codes for causing a computer to
compute a total benefit to a user equipment within a cell and to
one or more out-of-cell user equipment for one or more different
transmission attributes; and a second set of codes for causing the
computer to select at least one of the one or more different
transmission attributes that optimizes the total benefit to the
user equipment within a cell and to the one or more out-of-cell
user equipment, wherein the computing and the selecting is
performed by a base station within the cell.
11. An apparatus, comprising: means for computing a total benefit
to a user equipment within a cell and to one or more out-of-cell
user equipment for one or more different transmission attributes;
and means for selecting at least one of the one or more different
transmission attributes that optimizes the total benefit to the
user equipment within a cell and to the one or more out-of-cell
user equipment.
12. An apparatus, comprising: a resource coordination module
configured to: compute a total benefit to a user equipment within a
cell and to one or more out-of-cell user equipment for one or more
different transmission attributes; and select at least one of the
one or more different transmission attributes that optimizes the
total benefit to the user equipment within a cell and to the one or
more out-of-cell user equipment.
13. A method for facilitating interference management, the method
comprising: receiving, by user equipment, scheduling information to
contend for a resource; transmitting, by the user equipment, one or
more coordination messages to one or more base stations in response
to the received scheduling information; receiving, by the user
equipment, transmission attributes from at least one of the one or
more base stations; and transmitting, by the user equipment, an
estimated signal to interference and noise ratio or channel quality
indicator based on the received transmission attributes.
14. The method of claim 13, wherein one or more of the coordination
messages are interference management requests that include
information indicative of a request for a resource.
15. The method of claim 13, wherein each of the one or more
coordination messages includes one or more of a traffic priority
information, a channel strength information from the base station
to the user equipment, a channel strength information from a
serving base station to the user equipment, or a signal
interference information.
16. The method of claim 15, wherein the traffic priority
information is based on one or more of the following: a quality of
service characteristic, a quality of service class identifier
label, an average rate at which the user equipment has been served
in the past, a number of delays for packets in a buffer awaiting
transmission, head-of-line delay, buffer length in bytes or buffer
length in number of packets.
17. A computer program product, comprising: a computer-readable
medium, comprising: a first set of codes for causing a computer to
receive scheduling information to contend for a resource; a second
set of codes for causing the computer to transmit one or more
coordination messages to one or more base stations in response to
the received scheduling information; a third set of codes for
causing the computer to receive transmission attributes from at
least one of the one or more base stations; and a fourth set of
codes for causing the computer to transmit an estimated signal to
interference and noise ratio or channel quality indicator based on
the transmission attributes.
18. The computer program product of claim 17, wherein one or more
of the coordination messages to one or more base stations are
interference management requests that include information
indicative of a request for a resource.
19. The computer program product of claim 17, wherein each of one
or more coordination messages includes one or more of a traffic
priority information, a channel strength information from the base
station to the user equipment, a channel strength information from
a serving base station to the user equipment, or a signal
interference information.
20. The computer program product of claim 17, wherein the traffic
priority information is based on one or more of the following: a
quality of service characteristic, a quality of service class
identifier label, an average rate at which the user equipment has
been served in the past, a number of delays for packets in a buffer
awaiting transmission, head-of-line delay, buffer length in bytes
or buffer length in number of packets.
21. An apparatus comprising: means for receiving scheduling
information to contend for a resource; means for transmitting one
or more coordination messages to one or more base stations in
response to the received scheduling information; means for
receiving transmission attributes from at least one of the one or
more base stations; and means for transmitting an estimated signal
to interference and noise ratio or channel quality indicator based
on the received transmission attributes.
22. The apparatus of claim 21, wherein one or more of the
coordination messages are interference management requests that
include information indicative of a request for a resource.
23. The apparatus of claim 21, wherein each of one or more
coordination messages includes at least one of a traffic priority
information, a channel strength information from the base station
to the user equipment, a channel strength information from a
serving base station to the user equipment, or a signal
interference information.
24. The apparatus of claim 21, wherein the traffic priority
information is based on one or more of the following: a quality of
service characteristic, a quality of service class identifier
label, an average rate at which the user equipment has been served
in the past, a number of delays for packets in a buffer awaiting
transmission, head-of-line delay, buffer length in bytes or buffer
length in number of packets.
25. An apparatus comprising: a transceiver configured to: receive
scheduling information to contend for a resource; transmit one or
more coordination messages to one or more base stations in response
to the received scheduling information; receive transmission
attributes from at least one of the one or more base stations; and
transmit an estimated signal to interference and noise ratio or
channel quality indicator on a basis of based on the transmission
attributes.
26. The apparatus of claim 25, wherein one or more of the
coordination messages to one or more base stations are interference
management requests that include information indicative of a
request for a resource.
27. The apparatus of claim 25, wherein each of one or more
coordination messages includes one or more of a traffic priority
information, a channel strength information from the base station
to the user equipment, a channel strength information from a
serving base station to the user equipment, or a signal
interference information.
28. The apparatus of claim 25, wherein the traffic priority
information is based on one or more of the following: a quality of
service characteristic, a quality of service class identifier
label, an average rate at which the user equipment has been served
in the past, a number of delays for packets in a buffer awaiting
transmission, head-of-line delay, buffer length in bytes or buffer
length in number of packets.
29. A method for facilitating interference management on an uplink
of a wireless communication system, the method comprising:
determining, by a first base station, a benefit to a first user
equipment to which a transmission can be scheduled, the first user
equipment being in the first cell; determining, by the base
station, a degradation to a second user equipment in a second cell,
the degradation being associated with the transmission and
resulting from interference at a second base station in the second
cell that is caused by the first user equipment, the second cell
being different from the first cell; comparing the benefit to the
degradation; and scheduling the transmission by the first user
equipment if the benefit to the first user equipment is greater
than the degradation to the second user equipment.
30. A computer program product, comprising: a computer-readable
medium, comprising: a first set of codes for causing a computer to
determine a benefit to a first user equipment to which a
transmission can be scheduled, the first user equipment being in
the first cell; a second set of codes for causing the computer to
determine a degradation to a second user equipment in a second
cell, the degradation being associated with the transmission and
resulting from interference at a second base station in the second
cell that is caused by the first user equipment, the second cell
being different from the first cell; a third set of codes for
causing the computer to compare the benefit to the degradation; and
a fourth set of codes for causing the computer to schedule the
transmission by the first user equipment if the benefit to the
first user equipment is greater than the degradation to the second
user equipment.
31. An apparatus, comprising: means for determining a benefit to a
first user equipment to which a transmission can be scheduled, the
first user equipment being in the first cell; means for determining
a degradation to a second user equipment in a second cell, the
degradation being associated with the transmission and resulting
from interference at a second base station in the second cell that
is caused by the first user equipment, the second cell being
different from the first cell; means for comparing the benefit to
the degradation; and means for scheduling the transmission by the
first user equipment if the benefit to the first user equipment is
greater than the degradation to the second user equipment.
32. An apparatus, comprising: a resource coordination module
configured to: determine a benefit to a first user equipment to
which a transmission can be scheduled, the first user equipment
being in the first cell; determine a degradation to a second user
equipment in a second cell, the degradation being associated with
the transmission and resulting from interference at a second base
station in the second cell that is caused by the first user
equipment, the second cell being different from the first cell;
compare the benefit to the degradation; and schedule the
transmission by the first user equipment if the benefit to the
first user equipment is greater than the degradation to the second
user equipment.
33. A method for facilitating interference management on an uplink
of a wireless communication system, the method comprising:
receiving, by a base station in a first cell, a buffer status
request; and transmitting, by the base station, an interference
management request, wherein the interference management request is
based on the buffer status request.
34. The method of claim 33, wherein the transmitting the
interference management request comprises transmitting an
interference management request over-the-air to an out-of-cell user
equipment.
35. The method of claim 33, wherein the interference management
request is a resource utilization message.
36. The method of claim 33, further comprising scheduling, by the
base station, transmission of data from user equipment in the first
cell, wherein the scheduling is based on the information indicative
of intended transmit power.
37. The method of claim 33, further comprising scheduling, by the
base station, transmission of data from user equipment in the first
cell, wherein the scheduling is based on a determined priority of
traffic intended for the user equipment.
38. The method of claim 33, further comprising scheduling, by the
base station, transmission of data from user equipment in the first
cell, wherein the scheduling is based on interference information
associated with the user equipment.
39. The method of claim 38, wherein the interference information
comprises channel gain on resources assigned to the user equipment
or channel gains from the user equipment in the first cell to a
base station in a second cell.
40. A computer program product, comprising: a computer-readable
medium, comprising: a first set of codes for causing a computer to
receive a buffer status request; and a second set of codes for
causing the computer to transmit an interference management
request, wherein the interference management request is based on
the buffer status request, and wherein the receiving and the
transmitting is performed by a base station in a first cell.
41. The computer program product of claim 40, wherein transmitting
the interference management request comprises transmitting an
interference management request over-the-air to an out-of-cell user
equipment.
42. The computer program product of claim 40, wherein the
interference management request is a resource utilization
message.
43. The computer program product of claim 40, further comprising a
third set of codes for causing the computer to schedule
transmission of data from user equipment in the first cell, wherein
the scheduling is based on the information indicative of intended
transmit power.
44. The computer program product of claim 40, further comprising a
third set of codes for causing the computer to schedule
transmission of data from user equipment in the first cell, wherein
the scheduling is based on a determined priority of traffic
intended for the user equipment in the first cell.
45. The computer program product of claim 40, further comprising
scheduling transmission of data from user equipment in the first
cell, wherein the scheduling is based on interference information
associated with the user equipment in the first cell.
46. The computer program product of claim 45, wherein the
interference information comprises channel gain on resources
assigned to the user equipment in the first cell or channel gains
from the user equipment in the first cell to a base station in a
second cell.
47. An apparatus, comprising: means for receiving a buffer status
request; and means for transmitting an interference management
request, wherein the interference management request is based on
the buffer status request, and wherein the receiving and the
transmitting is performed by a base station in a first cell.
48. The apparatus of claim 47, wherein the transmitting the
interference management request comprises transmitting an
interference management request over-the-air to an out-of-cell user
equipment.
49. The apparatus of claim 47, wherein the interference management
request is a resource utilization message.
50. The apparatus of claim 47, further comprising means for
scheduling transmission of data from user equipment in the first
cell, wherein the scheduling is based on the information indicative
of intended transmit power.
51. The apparatus of claim 47, further comprising means for
scheduling transmission of data from user equipment in the first
cell, wherein the scheduling is based on a determined priority of
traffic intended for the user equipment in the first cell.
52. The apparatus of claim 47, further comprising means for
scheduling transmission of data from user equipment in the first
cell, wherein the scheduling is based on interference information
associated with the user equipment in the first cell.
53. The apparatus of claim 52, wherein the interference information
comprises channel gain on resources assigned to the user equipment
in the first cell or channel gains from the user equipment in the
first cell to a base station in a second cell.
54. An apparatus, comprising: a resource coordination module
configured to: receive a buffer status request; and transmit an
interference management request, wherein the interference
management request is based on the buffer status request, and
wherein the receiving and the transmitting is performed by a base
station in a first cell.
55. The apparatus of claim 54, wherein the transmitting the
interference management request comprises transmitting an
interference management request over-the-air to an out-of-cell user
equipment.
56. The apparatus of claim 54, wherein the interference management
request is a resource utilization message.
57. The apparatus of claim 54, further comprising scheduling
transmission of data from user equipment in the first cell, wherein
the scheduling is based on the information indicative of intended
transmit power.
58. The apparatus of claim 54, further comprising scheduling
transmission of data from user equipment in the first cell, wherein
the scheduling is based on a determined priority of traffic
intended for the user equipment in the first cell.
59. The apparatus of claim 54, further comprising scheduling
transmission of data from user equipment in the first cell, wherein
the scheduling is based on interference information associated with
the user equipment in the first cell.
60. The apparatus of claim 59, wherein the interference information
comprises channel gain on resources assigned to the user equipment
in the first cell or channel gains from the user equipment in the
first cell to a base station in a second cell.
Description
CROSS-REFERENCE
[0001] This application is a continuation of patent application
Ser. No. 12/698,349, filed Feb. 2, 2010 entitled "METHOD AND
APPARATUS FOR INTERFERENCE MANAGEMENT IN A WIRELESS COMMUNICATION
SYSTEM," pending, which claims the benefit of U.S. Provisional
Application Ser. No. 61/149,601, filed Feb. 3, 2009, and entitled
"A METHOD AND APPARATUS FOR DISTRIBUTED INTERFERENCE MANAGEMENT
SCHEMES FOR UNPLANNED DEPLOYMENTS", both of which are assigned to
the assignee hereof. The entirety of the foregoing Patent
Applications are incorporated herein by reference.
BACKGROUND
[0002] I. Field
[0003] The present disclosure relates generally to wireless
communications, and more specifically to techniques for managing
interference levels within a wireless communication
environment.
[0004] II. Background
[0005] Wireless communication systems are widely deployed to
provide various communication services; for instance, voice, video,
packet data, broadcast, and messaging services can be provided via
such wireless communication systems. These systems can be
multiple-access systems that are capable of supporting
communication for multiple terminals by sharing available system
resources. Examples of such multiple-access systems include Code
Division Multiple Access (CDMA) systems, Time Division Multiple
Access (TDMA) systems, Frequency Division Multiple Access (FDMA)
systems, and Orthogonal Frequency Division Multiple Access (OFDMA)
systems.
[0006] Generally, a wireless multiple-access communication system
can simultaneously support communication for multiple wireless
terminals. In such a system, each terminal can communicate with one
or more base stations via transmissions on the forward and reverse
links. The forward link (or downlink) refers to the communication
link from the base stations to the terminals, and the reverse link
(or uplink) refers to the communication link from the terminals to
the base stations. This communication link can be established via a
single-in-single-out (SISO), multiple-in-signal-out (MISO), or a
multiple-in-multiple-out (MIMO) system.
[0007] Wireless communication systems can be configured to include
a series of wireless access points, which can provide coverage for
respective locations within the system. Such a network structure is
generally referred to as a cellular network structure, and access
points and/or the locations they respectively serve in the network
are generally referred to as cells. In conventional wireless
network implementations, a set of base stations can be utilized to
provide network coverage for respective geographic areas
corresponding to the base stations. Further, power levels of
respective base stations in a wireless network can differ from base
station to base station, based on factors such as the relative
sizes of areas covered by the base stations and/or other such
factors. For example, macro base stations can be configured to
cover a large area and utilize a large power class, while pico base
stations, femto base stations, or the like can be configured to
cover a smaller area and utilize lower power.
[0008] In a wireless communication environment having unplanned
deployments, such as femto base stations or the like, interference
between respective communicating entities (e.g., base stations,
terminals, etc.) can cause significant degradation in system
communication performance. Moreover, in the event that such
interference is sufficiently large, outages can result in various
instances. Accordingly, it would be desirable to implement
techniques for resource control and interference management in a
wireless communication system.
SUMMARY
[0009] The following presents a simplified summary of various
aspects of the claimed subject matter in order to provide a basic
understanding of such aspects. This summary is not an extensive
overview of all contemplated aspects, and is intended to neither
identify key or critical elements nor delineate the scope of such
aspects. Its sole purpose is to present some concepts of the
disclosed aspects in a simplified form as a prelude to the more
detailed description that is presented later.
[0010] According to an aspect, a method is described herein. The
method can comprise identifying one or more priority parameters
associated with a communication link and a designated set of
resources for communication via the communication link;
constructing a resource utilization message (RUM), the RUM
comprising a request for reduction of transmit power on the
designated set of resources and a function of the one or more
priority parameters; and communicating the RUM to at least one
interfering network node.
[0011] A second aspect described herein relates to a wireless
communications apparatus, which can comprise a memory that stores
data relating to a communication link, one or more priority
parameters associated with the communication link, and a designated
set of resources for communication via the communication link. The
wireless communications apparatus can further comprise a processor
configured to construct a RUM, the RUM comprising a request for
reduction of transmit power on the designated set of resources and
a function of the one or more priority parameters, and to
communicate the RUM to at least one interfering network node.
[0012] A third aspect relates to an apparatus, which can comprise
means for constructing resource utilization messaging that includes
a request for power backoff on a specified set of resources and a
function of at least one priority metric associated with the
specified set of resources and means for communicating the resource
utilization messaging to at least one network node from which
interference is observed.
[0013] A fourth aspect described herein relates to a computer
program product, which can include a computer-readable medium that
comprises code for causing a computer to construct resource
utilization messaging that includes a request for power backoff on
a specified set of resources and a function of at least one
priority metric associated with the specified set of resources and
code for causing a computer to communicate the resource utilization
messaging to at least one network node from which interference is
observed.
[0014] According to a fifth aspect, a method is described herein
that can comprise obtaining respective RUMs requesting power
backoff on a specified set of resources, the respective RUMs
comprising one or more parameters constructed as a function of at
least one priority metric and determining an extent of power
backoff to be performed on the specified set of resources based on
the respective RUMs and the one or more parameters constructed as a
function of at least one priority metric within the respective
RUMs.
[0015] A sixth aspect described herein relates to a wireless
communications apparatus, which can comprise a memory that stores
data relating to respective RUMs requesting power backoff on a
specified set of resources, the respective RUMs comprising one or
more parameters constructed as a function of at least one priority
metric. The wireless communications apparatus can further comprise
a processor configured to determine an extent of power backoff to
be performed on the specified set of resources based on the
respective RUMs and the one or more parameters constructed as a
function of at least one priority metric within the respective
RUMs.
[0016] A seventh aspect relates to an apparatus, which can comprise
means for receiving resource utilization messaging that includes a
request for transmit power reduction on designated resources and a
function of one or more link quality metrics associated with the
designated resources and means for determining an amount of
transmit power reduction to be applied on the designated resources
based at least in part on the one or more parameters constructed as
a function of at least one priority metric provided in the resource
utilization messaging.
[0017] An eighth aspect described herein relates to a computer
program product, which can include a computer-readable medium that
comprises code for causing a computer to receive resource
utilization messaging that includes a request for transmit power
reduction on designated resources and a function of one or more
link quality metrics associated with the designated resources and
code for causing a computer to determine an amount of transmit
power reduction to be applied on the designated resources based at
least in part on the one or more parameters constructed as a
function of at least one priority metric provided in the resource
utilization messaging.
[0018] To the accomplishment of the foregoing and related ends, one
or more aspects of the claimed subject matter comprise the features
hereinafter fully described and particularly pointed out in the
claims. The following description and the annexed drawings set
forth in detail certain illustrative aspects of the claimed subject
matter. These aspects are indicative, however, of but a few of the
various ways in which the principles of the claimed subject matter
can be employed. Further, the disclosed aspects are intended to
include all such aspects and their equivalents.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a block diagram of a system for resource
coordination and interference management within a wireless
communication system in accordance with various aspects.
[0020] FIGS. 2-3 illustrate respective example procedures for
resource coordination in a wireless communication system in
accordance with various aspects.
[0021] FIG. 4 is a block diagram of a system for generating and
utilizing resource utilization messages for wireless interference
management in accordance with various aspects.
[0022] FIG. 5 illustrates example channel characteristics between
respective entities in a wireless communication system in
accordance with various aspects.
[0023] FIG. 6 illustrates an example system for resource contention
management in a wireless communication environment that can be
employed in accordance with various aspects described herein.
[0024] FIGS. 7-8 are flow diagrams of respective methodologies for
generating and transmitting signaling for interference management
in a wireless communication system.
[0025] FIG. 9 is a flow diagram of a methodology for processing
resource utilization messaging in association with resource and
interference management for a wireless communication system.
[0026] FIGS. 10-11 are block diagrams of respective apparatuses
that facilitate resource coordination and interference management
in a wireless communication network.
[0027] FIGS. 12-13 are block diagrams of respective wireless
communication devices that can be utilized to implement various
aspects described herein.
[0028] FIG. 14 illustrates a wireless multiple-access communication
system in accordance with various aspects set forth herein.
[0029] FIG. 15 is a block diagram illustrating an example wireless
communication system in which various aspects described herein can
function.
DETAILED DESCRIPTION
[0030] Various aspects of the claimed subject matter are now
described with reference to the drawings, wherein like reference
numerals are used to refer to like elements throughout. In the
following description, for purposes of explanation, numerous
specific details are set forth in order to provide a thorough
understanding of one or more aspects. It may be evident, however,
that such aspect(s) may be practiced without these specific
details. In other instances, well-known structures and devices are
shown in block diagram form in order to facilitate describing one
or more aspects.
[0031] As used in this application, the terms "component,"
"module," "system," and the like are intended to refer to a
computer-related entity, either hardware, firmware, a combination
of hardware and software, software, or software in execution. For
example, a component can be, but is not limited to being, a process
running on a processor, an integrated circuit, an object, an
executable, a thread of execution, a program, and/or a computer. By
way of illustration, both an application running on a computing
device and the computing device can be a component. One or more
components can reside within a process and/or thread of execution
and a component can be localized on one computer and/or distributed
between two or more computers. In addition, these components can
execute from various computer readable media having various data
structures stored thereon. The components can communicate by way of
local and/or remote processes such as in accordance with a signal
having one or more data packets (e.g., data from one component
interacting with another component in a local system, distributed
system, and/or across a network such as the Internet with other
systems by way of the signal).
[0032] Furthermore, various aspects are described herein in
connection with a wireless terminal and/or a base station. A
wireless terminal can refer to a device providing voice and/or data
connectivity to a user. A wireless terminal can be connected to a
computing device such as a laptop computer or desktop computer, or
it can be a self contained device such as a personal digital
assistant (PDA). A wireless terminal can also be called a system, a
subscriber unit, a subscriber station, mobile station, mobile,
remote station, access point, remote terminal, access terminal,
user terminal, user agent, user device, or user equipment (UE). A
wireless terminal can be a subscriber station, wireless device,
cellular telephone, PCS telephone, cordless telephone, a Session
Initiation Protocol (SIP) phone, a wireless local loop (WLL)
station, a personal digital assistant (PDA), a handheld device
having wireless connection capability, or other processing device
connected to a wireless modem. A base station (e.g., access point
or Node B) can refer to a device in an access network that
communicates over the air-interface, through one or more sectors,
with wireless terminals. The base station can act as a router
between the wireless terminal and the rest of the access network,
which can include an Internet Protocol (IP) network, by converting
received air-interface frames to IP packets. The base station also
coordinates management of attributes for the air interface.
[0033] Moreover, various functions described herein can be
implemented in hardware, software, firmware, or any combination
thereof. If implemented in software, the functions can be stored on
or transmitted over as one or more instructions or code on a
computer-readable medium. Computer-readable media includes both
computer storage media and communication media including any medium
that facilitates transfer of a computer program from one place to
another. A storage media can be any available media that can be
accessed by a computer. By way of example, and not limitation, such
computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or
other optical disk storage, magnetic disk storage or other magnetic
storage devices, or any other medium that can be used to carry or
store desired program code in the form of instructions or data
structures and that can be accessed by a computer. Also, any
connection is properly termed a computer-readable medium. For
example, if the software is transmitted from a website, server, or
other remote source using a coaxial cable, fiber optic cable,
twisted pair, digital subscriber line (DSL), or wireless
technologies such as infrared, radio, and microwave, then the
coaxial cable, fiber optic cable, twisted pair, DSL, or wireless
technologies such as infrared, radio, and microwave are included in
the definition of medium. Disk and disc, as used herein, includes
compact disc (CD), laser disc, optical disc, digital versatile disc
(DVD), floppy disk and blu-ray disc (BD), where disks usually
reproduce data magnetically and discs reproduce data optically with
lasers. Combinations of the above should also be included within
the scope of computer-readable media.
[0034] Various techniques described herein can be used for various
wireless communication systems, such as Code Division Multiple
Access (CDMA) systems, Time Division Multiple Access (TDMA)
systems, Frequency Division Multiple Access (FDMA) systems,
Orthogonal Frequency Division Multiple Access (OFDMA) systems,
Single Carrier FDMA (SC-FDMA) systems, and other such systems. The
terms "system" and "network" are often used herein interchangeably.
A CDMA system can implement a radio technology such as Universal
Terrestrial Radio Access (UTRA), CDMA2000, etc. UTRA includes
Wideband-CDMA (W-CDMA) and other variants of CDMA. Additionally,
CDMA2000 covers the IS-2000, IS-95 and IS-856 standards. A TDMA
system can implement a radio technology such as Global System for
Mobile Communications (GSM). An OFDMA system can implement a radio
technology such as Evolved UTRA (E-UTRA), Ultra Mobile Broadband
(UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20,
Flash-OFDM.RTM., etc. UTRA and E-UTRA are part of Universal Mobile
Telecommunication System (UMTS). 3GPP Long Term Evolution (LTE) is
an upcoming release that uses E-UTRA, which employs OFDMA on the
downlink and SC-FDMA on the uplink. UTRA, E-UTRA, UMTS, LTE and GSM
are described in documents from an organization named "3rd
Generation Partnership Project" (3GPP). Further, CDMA2000 and UMB
are described in documents from an organization named "3rd
Generation Partnership Project 2" (3GPP2).
[0035] Various aspects will be presented in terms of systems that
can include a number of devices, components, modules, and the like.
It is to be understood and appreciated that the various systems can
include additional devices, components, modules, etc. and/or omit
some or all of the devices, components, modules etc. discussed in
connection with the figures. A combination of these approaches can
also be used.
[0036] Referring now to the drawings, FIG. 1 illustrates a system
100 for resource coordination and interference management within a
wireless communication system in accordance with various aspects
described herein. As FIG. 1 illustrates, system 100 can include one
or more Evolved Node Bs (eNBs; also referred to herein as Node Bs,
cells or network cells, base stations, access points (APs), etc.)
110, which can communicate with one or more user equipment units
(UEs; also referred to herein as access terminals (ATs), mobile
terminals, mobile stations, etc.) 120. While only one eNB 110 and
UE 120 are illustrated in FIG. 1, it should be appreciated that
system 100 can include any number of eNBs 110 and/or UEs 120.
Further, it can be appreciated that respective eNBs 110 in system
100 can serve any suitable coverage area, such as an area
associated with a macro cell, a femto cell (e.g., an access point
base station or Home Node B (HNB)), and/or any other suitable type
of coverage area.
[0037] In accordance with one aspect, UE 120 can engage in one or
more uplink (UL, also referred to herein as reverse link (RL))
communications with eNB 110, and similarly eNB 110 can engage in
one or more downlink (DL, also referred to herein as forward link
(FL)) communications to UE 120. Additionally or alternatively, Node
B 110 and/or UE 120 can engage in any suitable communication(s)
with each other, with other devices or entities in system 100,
and/or any other suitable entities. In one example, UL and/or DL
communication between eNB 110 and UE 120 can additionally result in
interference to nearby eNBs, UEs, and/or other devices (not shown).
For example, in a system with multiple eNBs 110 and/or UEs 120, a
UE located in an area that lies in an overlap between the coverage
of multiple eNBs can cause interference to one or more eNBs within
range of the UE with which the UE is not communicating, other UEs,
and/or other devices under various circumstances. Interference as
caused in this manner can be a significant concern in the case of
unplanned deployments (such as femto eNBs), where interference can
cause significant performance degradation, including outage in some
instances.
[0038] In view of interference that can be caused within system 100
due to unplanned deployments and/or other causes, respective
entities in system 100 can in accordance with one aspect engage in
resource coordination to mitigate interference experienced within
system 100. For example, respective entities in system 100 can
utilize a distributed coordination scheme and/or other suitable
schemes, wherein respective eNBs maintain reasonable quality of
service (QoS) performance and shared media are utilized in an
overall efficient manner. To these ends, eNB 110 can utilize a
resource coordination module 112, which can operate to coordinate
control resource usage between eNB 110 and UE 120 as described
herein to mitigate the effects of interference between entities in
system 100. In one example, if eNB 110 and UE 120 are configured to
utilize overlapping sets of communication resources in time (e.g.,
subframes, interlaces, etc.), frequency (e.g., sub-bands, etc.),
code, or the like, resource coordination module 112 at eNB 110 can
facilitate coordination between the overlapping resources such that
interference is minimized between transmissions conducted over the
overlapping resources by various entities in system 100.
[0039] As further shown in system 100, UE 120 can utilize a
reservation request module 122, which can facilitate interference
management by requesting power backoff (e.g., a reduction in
transmit power or transmit power spectral density (PSD), silence or
non-transmission, etc.) by one or more interfering entities on
particular frequency sub-bands, subframes or interlaces in time,
etc., on which UE 120 is configured for communication with eNB 110
and/or other entities within system 100. Accordingly, by way of
specific, non-limiting example, reservation request module 122 at
UE 120 can be utilized to enable UE 120 to establish a connection
with a serving eNB in the presence of other interfering eNBs. In
another example, resource coordination module 112 at eNB 110 can be
utilized to coordinate usage of control resources and/or data
resources between eNB 110 and UE 120. Techniques that can be
implemented by eNB 110 and/or UE 120 for resource control and
interference management are described in further detail herein.
[0040] In one example, reservation request module 122 at UE 120 can
facilitate interference management within system 100 by generating
and communicating resource utilization messages (RUMs) to various
entities in system 100. Further, RUM generation and communication
can be performed in response to a prompt from an eNB 110 that
serves UE 120. For example, as shown by FIG. 2, an eNB can
initially provide a RUM request to a UE as illustrated by diagram
202. Next, as illustrated by diagram 204, the UE receiving the RUM
request can prepare RUM messaging, which can subsequently be
provided to one or more interfering eNBs. RUM messaging transmitted
by a UE as shown in diagram 204 can, for example, specify resources
on which reservation and/or power backoff is desired. In addition,
RUM messaging transmitted as shown in diagram 204 can contain one
or more parameters constructed to aid a receiving entity in
determining whether to honor the RUM messaging. Specific examples
of techniques that can be utilized for constructing and
communicating RUM messaging are provided in further detail
herein.
[0041] Upon receiving a RUM from a UE as shown by diagram 204, an
eNB can perform one or more utility-based, priority-based, and/or
other computations to determine whether and/or to what extent to
honor the RUM. For example, in response to a RUM, an eNB can elect
to do nothing (e.g., and continue transmitting at full power),
conduct a partial or full power backoff on resources designated in
the RUM, and/or perform any other suitable action(s). In one
example, an eNB can provide a RUM response to the UE from which the
RUM was received that indicates the action(s) elected by the eNB.
This is illustrated by diagram 206. Subsequently, the UE can
estimate a channel quality that will result based on the action(s)
indicated in the RUM response provided as shown by diagram 206.
Based on this estimation, the UE can convey a quality report to its
serving eNB, as illustrated by diagram 208.
[0042] In one example, a RUM can serve as a message transmitted
from a given entity (e.g., eNB, UE, etc.) in a wireless
communication system that requests respective interferers to the
entity to clear particular resources. A RUM can be, for example, a
downlink RUM (D-RUM), which can be provided by respective eNBs to
clear UL interference. Additionally or alternatively, a RUM can be
an uplink RUM (U-RUM), which can be provided by respective UEs to
clear DL interference. While various examples provided herein
relate specifically to U-RUM or D-RUM generation and management, it
should be appreciated that respective techniques as provided herein
can be utilized both for U-RUM and D-RUM management. Thus, for
example, while not illustrated in FIG. 1, eNB 100 can include a
reservation request module 122 that can function as generally
described herein with respect to reservation request module 122 at
UE 120, and UE 120 can include and/or otherwise utilize a resource
coordination module 112 that can operate in a similar manner to a
resource coordination module 112 at eNB 110. Further, it should be
appreciated that, unless explicitly stated otherwise, the hereto
appended claims are not intended to be limited to any such specific
implementation(s).
[0043] In accordance with another aspect, an eNB 110 and UE 120 as
illustrated by system 100 in FIG. 1 can operate according to a
dynamic avoidance timeline in order to facilitate resource
contention and partitioning, interference management, and/or other
performance improvements for system 100. By doing so, it can be
appreciated that respective entities in system 100 can be given
access to substantially all bandwidth associated with system 100 on
a short-term basis as and when needed, thereby mitigating
performance degradation associated with traditional network
deployments.
[0044] In one example, a dynamic avoidance timeline utilized by eNB
110 and UE 120 can utilize a RUM procedure similar to that
illustrated by FIG. 2. Additionally or alternatively, operation of
an example dynamic avoidance procedure that can be performed
between eNB 110 and UE 120 in time is illustrated by diagram 300 in
FIG. 3. As diagram 300 illustrates, a UE, a serving node (or eNB)
for the UE, and a node (or eNB) causing interference to the UE can
utilize a dynamic interference procedure over a series of
subframes. As illustrated in diagram 300, subframes as observed at
the UE and respective eNBs are represented as blocks.
[0045] As the process illustrated in diagram 300 begins, it can be
observed that the serving node of a UE that is experiencing
interference from an interfering node can provide a RUM request to
the UE at subframe t, which is a request that triggers the
following avoidance timeline at the UE. Next, at subframe t+2, the
UE can communicate a RUM, such as a U-RUM to the interfering node
in response to the RUM request. The RUM can, for example, carry
information needed at the interfering eNB to make a decision with
respect to whether to honor the RUM. For example, the RUM can carry
information relating to the priority of the UE and the traffic with
which it will be served, a designated set of affected resources,
channel and/or spectral efficiency information (e.g., in order to
enable the interfering eNB to determine the short-term impact of
allocating the affected resources for the UE as opposed to serving
other UEs with the affected resources), or the like. In one
example, a UE can obtain at least a portion of information included
within a U-RUM from its serving eNB. Thus, for example, portions of
the U-RUM that are known at the serving eNB (e.g., resource
identifiers, priority information, traffic scheduler metrics,
latency metrics for QoS-sensitive traffic, etc.) can be carried by
a RUM request from the serving eNB to the UE. The UE can
subsequently combine this information with additional information
known to the UE, such as cross-link channel characteristics,
interference information, or the like, and the combined information
can be provided in a RUM to an interfering eNB.
[0046] Upon receiving a U-RUM, an interfering eNB can perform
respective calculations relating to, for example, comparisons
between allocating resources specified in the U-RUM to the
requesting UE or serving other UEs with the specified resources.
Based on these calculations, the interfering eNB can make a
decision regarding whether and/or to what extent to honor the RUM.
The decision of the interfering eNB can subsequently be indicated
back to the UE at subframe t+4. In one example, the interfering eNB
can indicate its decision to the UE via a pilot transmission and/or
another suitable transmission. By way of specific example, the
transmission of the interfering eNB can be carried out over a power
decision pilot indicator channel (PDPICH) and/or another suitable
channel. For example, a DL PDPICH (D-PDPICH) can be utilized in
response to a U-RUM to indicate a commitment of the power to be
utilized on a subsequent transmission (e.g., on resources indicated
by the U-RUM), which in turn can allow receivers of the D-PDPICH
transmission to estimate the channel quality expected on a
particular resource. While D-PDPICH transmission is illustrated in
diagram 300, however, it should be appreciated that UL PDPICH
(U-PDPICH) transmission can be conducted (e.g., by a UE to an eNB
in response to a D-RUM) in a similar manner.
[0047] As shown in diagram 300, pilots can be transmitted on
D-PDPICH by substantially all eNBs in an associated system,
including interfering eNBs and serving eNBs. For example, pilots
transmitted on D-PDPICH can serve as an advance notice of an amount
of power to be utilized by the corresponding eNB(s) on specified
resources at a predetermined time in the future (e.g., 4 subframes
later). By doing so, respective UEs can be enabled to make
measurements and accurately predict the amount of interference that
they will observe at the point in time corresponding to the
D-PDPICH transmissions.
[0048] Next, at subframe t+6, the UE can perform respective
measurements and/or perform other appropriate actions in order to
compute per-resource channel quality information. Such computations
can, for example, be resource-specific and based on advance notice
provided in D-PDPICH transmissions, as opposed to traditional
channel quality information (CQI) computations that are averaged
over time for all resources. Upon computing resource-specific
quality parameters (also referred to herein as resource quality
indicators or RQI), the UE can provide the parameters to its
serving UE over a RQI channel (e.g., an uplink RQI channel or
U-RQICH). In one example, the serving eNB for the UE can utilize
RQI transmissions from the UE in performing scheduling, rate
prediction, or the like. Further, based on the RQI parameters
provided by the UE, the serving eNB can infer whether respective
interfering eNBs have honored the RUM provided by the UE. For
example, if the RQI reported by the UE is substantially low, the
serving eNB can infer that the RUM was not honored. In such a case,
the serving eNB can decide not to schedule the UE, or can decide to
schedule a different UE experiencing less interference on the given
resources, as different UEs can in some circumstances experience
different amounts of interference from different eNBs.
Alternatively, if the serving eNB deems the RQI reported by the UE
acceptable, the serving eNB can proceed with scheduling for the
UE.
[0049] Subsequent to scheduling by the serving eNB, communication
between the UE and its serving eNB can proceed as shown in the
remaining subframes in diagram 300 as generally known in the art.
For example, the serving eNB for the UE can provide a downlink
grant and a physical downlink shared channel (PDSCH) transmission
to the UE, based on which the UE can provide an UL acknowledgement
(ACK). Subsequently, PDSCH and ACK transmission can continue in the
manner provided by diagram 300 for a predetermined number x of
radio frames.
[0050] As illustrated by diagram 300, it can be appreciated that
dynamic avoidance channels (e.g., RUM Request, RUM, etc.) can be
sent only once to negotiate resources between respective network
entities on substantially all interlaces. Subsequently, channels
such as grants, ACK, etc., can be sent on all interlaces. In one
example, coordination between network entities as illustrated by
system 300 can be a single subframe and pipelined for substantially
all scheduled subframes. Alternatively, coordination can be
performed for a longer priority period (e.g., a fixed number of
subframes, a fixed time period, etc.). In another example, a
predefined amount of latency can be allowed in the timeline
illustrated by diagram 300 for resource negotiation, processing
time, or the like.
[0051] Turning next to FIG. 4, a block diagram of a system 400 for
generating and utilizing resource utilization messages for wireless
interference management in accordance with various aspects is
illustrated. As shown in system 400, a UE 120 can interact with
respective eNBs, such as a serving eNB 410 and an interfering eNB
430. As shown in system 400 and described herein, various
techniques for DL resource management in a scenario where each UE
120 is associated with one serving eNB 410 (e.g., where there is no
notion of scheduling among UEs associated with a sector, etc.) are
provided. However, it should be appreciated that the techniques
described herein can be extended to UL resource management and/or
multi-eNB deployments, and that unless explicitly stated otherwise
the claimed subject matter is not intended to be limited to any
particular implementation(s).
[0052] In accordance with one aspect, system 400 can approach
resource management as a distributed optimization problem that
utilizes a utility function that converts priority parameters,
spectral efficiency parameters, and the like into scalar values
that can be compared and maximized. In one example, memoryless
algorithms are utilized that avoid making interferences relating to
"average" states of respective users explicitly or implicitly
(e.g., such that responses are based only upon a current priority,
rate, etc.). It can be appreciated that algorithms as provided
herein enable robust resource management that can work for any
network topology, size, geometry, or utility function(s). For
example, a changing utility function can be utilized to effectively
control fairness.
[0053] In general, it can be further appreciated that system 400
can facilitate resource control by adjusting transmit powers
associated with respective links (e.g., transmitter/receiver pairs)
in system 400 such that an overall utility (e.g., expressed in
terms of rate, priority, or the like) associated with system 400 is
maximized. For example, system 400 can be configured such that a
link yields to another link only if yielding would lead to an
improvement in net utility. In one example, respective links in
system 400 can manage resources based only on instantaneous
information relating to the QoS of other links, thereby enhancing
support for handling bursty and/or delay-sensitive traffic.
Further, to enhance decentralized resource control operation,
system 400 can impose controls that prohibit excessive power
backoff, facilitate randomization, and/or further other appropriate
ends.
[0054] In the following description, specific, non-limiting
examples of techniques that can be utilized by system 400 for
interference and resource management are provided. It should be
appreciated, however, that the examples provided herein are not
intended as an exhaustive listing of the implementations that can
be utilized for carrying out such ends. With regard to the below
examples, the following notations and definitions apply. It is
reiterated that the following definitions and notations are
provided merely by way of illustration and are not intended to
limit the scope of the subject matter claimed herein. As utilized
herein, system 400 can be configured to include N eNBs and N UEs
such that exactly one UE is associated with each eNB. Thus, system
400 can be associated with N links, denoted as links {1, . . . ,
N}. Further, channel gain is denoted as h( ), where h(i) denotes
channel gain from an i-th eNB to an i-th UE, h(i,j) denotes channel
gain from an i-th eNB to a j-th UE, and h(j) denotes channel gain
from a j-th eNB to a j-th UE. These relationships are illustrated
by diagram 500 in FIG. 5. As further utilized herein, P.sub.max(i)
is the maximum transmit power of an i-th eNB. Further, an i-th eNB
can transmit at M power levels given by {P.sub.1(i), . . .
P.sub.M(i)=P.sub.max(i)}. In addition, each UE can be associated
with a utility function of its average rate, priority, and/or other
suitable parameters, which can be denoted as U.sub.i(x.sub.i) for
an i-th UE. Thus, the goal of a distributed algorithm as
implemented by system 400 can be to maximize the overall utility of
system 400, which can be denoted as
i = 1 N U i ( x i ) , ##EQU00001##
with low overhead.
[0055] In accordance with one aspect as illustrated by system 400,
UE 120 can utilize a reservation request module 122 to facilitate
resource control and interference management in relation to a
communication link between serving eNB 410 and UE 120. For example,
reservation request module 122 can identify one or more priority
parameters 422 and/or one or more rate parameters 424 associated
with a communication link associated with UE 120 and its serving
eNB 410. In addition, reservation request module 122 can identify a
designated set of resources for communication via the communication
link. Based on these identified parameters, reservation request
module 122 can construct a RUM that includes a request for
reduction of transmit power at one or more interfering eNBs 430 on
the designated set of resources as well as a function of the one or
more priority parameters 422 and/or the one or more rate parameters
424. Upon construction of a RUM, UE 120 can communicate the RUM to
at least one interfering network node, such as interfering eNB
430.
[0056] In one example, serving eNB 410 can utilize a RUM
instruction module 412 and/or other suitable means to transmit a
RUM request to UE 120 as generally described above. Upon receipt of
a RUM request, UE 120 can construct and communicate a RUM in
various manners as set forth in further detail herein.
[0057] In accordance with another aspect, UE 120 can construct RUMs
for transmission to various interfering eNBs 430 using various sets
of information. By way of a first specific, non-limiting example, a
RUM generated by UE 120 can include two terms, including a first
term given as an incremental scheduler metric function U'(x(i)) of
the average or cumulative rate presently achieved by the UE 120
(e.g., as provided by rate parameters 424) and a second term that
indicates a maximum transmit power of serving eNB 410 multiplied by
a channel gain from serving eNB 410 to UE 120 in relation to a
nominal interference value I.sub.nom(i). Accordingly, a RUM
prepared by UE 120 can be expressed as (U'(x(i)),
P max ( i ) h ( i ) I nom ( i ) ) . ##EQU00002##
As used herein, the nominal interference value I.sub.nom(i)
corresponds to an interference that link i (e.g., corresponding to
an i-th serving eNB 410 and UE 120) would expect to observe if all
other transmitters (e.g., interfering eNBs 430) back off as
expected in response to the corresponding RUM. Accordingly, in one
example, UE 120 can compute the nominal interference value
I.sub.nom(i) at least in part by predicting a total amount of
interference caused by at least one interfering eNB 430 in the
event that the corresponding RUM is accepted by substantially all
interfering eNBs 430.
[0058] In another example, UE 120 can be configured to communicate
a RUM at a transmit power determined as a function of the maximum
transmit power of serving eNB 410 and the channel gain between
serving eNB 410 and UE 120. Thus, for example, UE 120 can modulate
information relating to a communication link between serving eNB
410 and UE 120 in the power of a communicated RUM by selecting RUM
transmit power to be inversely proportional to channel gain. More
particularly, an i-th UE 120 can conduct RUM signaling at a
transmit power
P RUM ( i ) = K h ( i ) P max ( i ) ##EQU00003##
for a system-wide known constant K, based on which a j-th
interfering eNB 430 can receive the RUM signaling with power
P RX ( i ) = Kh ( i , j ) h ( i ) P max ( i ) . ##EQU00004##
Additionally or alternatively, information relating to channel gain
and/or other suitable parameters can be explicitly provided (e.g.,
in the payload of the RUM signaling). Subsequently, based on
implicit and/or explicit information associated with received RUM
signaling, a j-th interfering eNB 430 can infer
log ( 1 + h ( i ) P ma x ( i ) I nom ( i ) ) , log ( 1 + h ( i ) P
ma x ( i ) h ( i , j ) P ma x ( j ) + I nom ( i ) ) ,
##EQU00005##
or the like.
[0059] In an additional example RUM configuration, UE 120 can be
configured (e.g., in the case of QoS-sensitive traffic) to
incorporate respective QoS metrics and/or other priority parameters
422 into RUM signaling in addition to, and/or in place of, rate
parameters 424 as described above. Thus, for example, the
incremental scheduler metric function U'(x(i)) as described above
can be replaced with a function of respective priority metrics
relating to QoS- and/or delay-sensitive traffic. These parameters
can include, for example, a head-of-line delay D.sub.HOL
corresponding to a packet flow associated with a communication link
between serving eNB 410 and UE 120, a queue length q corresponding
to such a packet flow, a burst size S of such a packet flow, a
delay target D.sub.TARG for such a packet flow, an average rate at
which an associated communication link has been served (e.g., at
one or more times in the past), and/or other suitable parameters.
Thus, by way of illustration, U'(x(i)) can be replaced with a
function f(D.sub.HOL,q,s,D.sub.TARG) and/or another suitable
function of respective priority parameters 422 of interest. By way
of specific example, a function f(q.sub.i,D.sub.i) or
f(q.sub.i,D.sub.i)r.sub.i can be utilized as a utility function for
resource management in relation to an i-th eNB/UE link, where
q.sub.i represents buffer length for an i-th UE, D.sub.i represents
head-of-line delay for the i-th UE, and r.sub.i represents the
spectral efficiency achievable on the link between the i-th UE and
its serving eNB. By utilizing QoS-driven priority parameters 422 as
a basis for interference management in this manner, it can be
appreciated that system 400 can facilitate queue stabilization,
improved delay performance, and other suitable benefits even in the
presence of time-varying ergodic channels.
[0060] In accordance with one aspect, UE 120 can generate and
transmit respective RUMs to one or more interfering eNBs 430 as
described above. Subsequently, an interfering eNB 430 can obtain
respective RUMs requesting power backoff on a specified set of
resources and utilize a utility computation module 432, a power
control module 434, and/or other suitable means to determine an
extent of power backoff to be performed on the specified set of
resources based on the respective RUMs and parameters associated
with the respective RUMs.
[0061] By way of specific example, respective RUMs received by an
interfering eNB 430 can comprise one or more parameters that are
constructed as a function of at least one priority metric (e.g.,
associated with priority parameters 422). Thus, for example, a RUM
received at interfering eNB 430 can be constructed in a similar
manner to that described above, e.g., (f(q.sub.i,D.sub.i),
P ma x ( i ) h ( i ) I nom ( i ) , ##EQU00006##
Resource), to convey information relating to priority metrics
associated with a link between an i-th serving eNB 410 and an i-th
UE 120, power/interference parameters, and the identity(-ies) of
the resource(s) on which the RUM is requesting power backoff. While
the specific function f(q.sub.i,D.sub.i) is utilized herein, it
should nonetheless be appreciated that any suitable function of
priority metrics, such as head-of-line delays, queue lengths, burst
sizes, delay targets, average past rates, etc., corresponding to
respective packet flows associated with respective communication
links, and/or any other suitable metric(s), could be utilized.
[0062] Based on the specific, non-limiting example RUM structure
provided above, interfering eNB 430 can determine whether and to
what extent to perform power backoff on the resource(s) specified
in the RUM in a variety of manners. In a first example, a binary
approach can be utilized, wherein interfering eNB 430 can compute a
first QoS change associated with silencing communication on the
specified set of resources provided in a RUM and a second QoS
change associated with performing no power backoff on the specified
set of resources (e.g., transmitting at a maximum transmit power
P.sub.max(i)) on the specified set of resources). For example, the
first QoS change can be expressed as follows:
.DELTA. U ( 0 ) = max i .di-elect cons. { RUMs decoded } f ( q i ,
D i ) log ( 1 + h ( i ) P max ( i ) I nom ( i ) ) ,
##EQU00007##
and the second QoS change can be expressed as follows:
.DELTA. U ( P max ( i ) ) = f ( q i , D i ) log ( 1 + h ( j ) P max
( i ) I ) + max i .di-elect cons. { RUMs decoded } f ( q i , D i )
log ( 1 + h ( i ) P max ( i ) h ( i , j ) P max ( j ) + I nom ( i )
) , ##EQU00008##
where I is set to I.sub.nom(j) if a j-th UE has provided a RUM and
reuse-one interference otherwise. Upon performing the above
computations, power control module 434 and/or other suitable
mechanisms associated with interfering eNB 430 can determine
whether or not to back off in power based on the utility increase
or QoS change that is higher. For example, interfering eNB 430 can
be configured to grant a corresponding RUM at least in part by
silencing transmission on a specified set of resources associated
with the RUM upon determining that the first QoS change as provided
above is greater than the second QoS change. Alternatively,
interfering eNB 430 can be configured to deny the RUM at least in
part by performing substantially no power backoff on the set of
resources specified by the RUM upon determining that the second QoS
change is greater than the first QoS change.
[0063] In another example, a similar binary technique to that
provided above can be utilized by interfering eNB 430 in the event
that RUM signaling provided by one or more UEs 120 is given in
terms of rate parameters 424, e.g., (U'(x(i)),
P max ( i ) h ( i ) I nom ( i ) , ##EQU00009##
Resource). For example, utility computation module 432 and/or other
suitable mechanisms at interfering eNB 430 can compute a first
change in utility that corresponds to a total utility achievable
within system 400 in the event that interfering eNB 430 does not
communicate on requested resources and a second change in utility
that corresponds to a combined utility within system 400 resulting
from transmission by both interfering eNB 430 and serving eNB 410
on the requested resources (e.g., in terms of an increased utility
for interfering eNB 430 offset by a decreased utility for serving
eNB 410). These metrics can be computed as follows:
.DELTA. U ( 0 ) = max i .di-elect cons. { RUMs decoded } U ' ( x (
i ) ) log ( 1 + h ( i ) P max ( i ) I nom ( i ) ) , .DELTA. U ( P
max ( i ) ) = U ' ( x ( j ) ) log ( 1 + h ( j ) P max ( i ) I ) +
max i .di-elect cons. { RUMs decoded } U ' ( x ( i ) ) log ( 1 + h
( i ) P max ( i ) h ( i , j ) P max ( j ) + I nom ( i ) ) ,
##EQU00010##
where I is set to I.sub.nom(j) if a j-th UE has provided a RUM and
reuse-one interference otherwise. Based on the results of such
calculations, interfering eNB 430 can be configured to conduct full
backoff or no backoff in a similar manner to that described
above.
[0064] In accordance with another aspect, interfering eNB 430 can
alternatively compute QoS and/or utility changes associated with a
plurality of power backoff levels on a RUM-specified set of
resources, such that interfering eNB 430 can back off power on the
RUM-specified set of resources according to a power backoff level
determined to have a highest QoS and/or utility change from among
the plurality of power backoff levels. In one example, in a
scenario where multiple transmit power levels P .epsilon.
{P.sub.1(j), . . . , P.sub.M(j)} are allowed at a j-th interfering
eNB 430, interfering eNB 430 can compute respective utility changes
associated with respective power levels P as follows:
.DELTA. U ( P ) = max i .di-elect cons. { RUMs decoded } U ' ( x (
i ) ) log ( 1 + h ( i ) P max ( i ) h ( i , j ) + I nom ( i ) ) + I
[ UE j sent RUM ] U ' ( x ( j ) ) log ( 1 + h ( j ) P I nom ( j ) )
+ I [ UE j did not RUM ] U ' ( x ( j ) ) log ( 1 + h ( j ) P I
reuse - one ) . ##EQU00011##
Based on the above calculations, interfering eNB 430 can select a
transmit power given by P=arg max.sub.P.sub.1.sub.(j), . . . ,
P.sub.M.sub.(j).DELTA.U(P). Similarly, by substituting f(q.sub.i,
D.sub.i) and/or a similar function of priority and/or QoS metrics
for U'(x(i)) in the above computations, power backoff selection can
additionally or alternatively be performed based on priority
parameters 422.
[0065] As further noted above, RUMs provided by respective UEs 120
to an interfering eNB 430 can include parameters relating to
maximum transmit powers of respective serving eNBs 410 to the UEs
120, parameters relating to channel gain associated with respective
communication links between the UEs 120 and their respective
serving eNBs 410, nominal interference parameters, or the like. In
one example, interfering eNB 430 can be further configured to
identify such parameters and/or one or more other suitable
parameters associated within a RUM based on a received power of the
RUM. By way of example, in the event that cross-channel gain is
encoded into the power of a transmitted RUM, a receiver of the RUM
can compute the rate for an i-th link based on a transmit power P
of a j-th link based on
log ( 1 + h ( i ) P max ( i ) h ( i , j ) P ( j ) + I nom ( i ) ) =
log ( 1 + 1 h ( i , j ) h ( i ) P max ( i ) P + I nom ( i ) h ( i )
P max ( i ) ) . ##EQU00012##
Additionally or alternatively, it can be appreciated that
cross-channel gain can be encoded into the payload of RUM
signaling. In one example, the manner in which gain information is
incorporated into RUM signaling can depend on how the signaling is
transmitted. For example, unicast RUM signaling can include
explicitly encoded gain information broadcast RUM signaling can
include power-modulated gain information.
[0066] In accordance with a further aspect, upon determining an
extent of power backoff to be applied on resources specified by
respective RUMs, interfering eNB 430 can signal the extent of power
backoff to be performed on the specified set of resources in a
pilot transmission to UE(s) 120. Upon receiving such pilot
signaling from at least one interfering eNB 430 (e.g., in response
to a RUM provided to the at least one interfering eNB 430), UE 120
can estimate channel quality associated with a designated set of
resources based at least in part on the pilot signaling.
Subsequently, a resource quality reporter 426 and/or other means at
UE 120 can be utilized to report estimated channel quality
associated with the designated set of resources to serving eNB 410,
which in turn can utilize a transmission scheduler 414 to schedule
communication between serving eNB 410 and UE 120 based on the
reported information.
[0067] In accordance with still another aspect, RUM generation
and/or signaling for QoS traffic as generally described above can
be based on arrival processes associated with respective packets
corresponding to UE 120. For example, packets can arrive at UE 120
according to one or more arrival processes corresponding to an
arrival rate that can be independent of scheduling processes
associated with UE 120. Further, respective statistics of the
arrival process(es) associated with UE 120 may or may not be known
by UE 120. By utilizing the techniques described above for such a
system, it can be appreciated that the overall performance of UE
120 can be improved by, for example, reducing tail delays,
stabilizing queues (e.g., by controlling delays and buffer sizes,
etc.), and/or achieving other appropriate ends.
[0068] Referring now to FIG. 6, an example system 600 for resource
contention management in a wireless communication environment that
can be employed in accordance with various aspects described herein
is illustrated. As shown in FIG. 6, system 600 can include a
resource coordination module 112, which can be incorporated by a UE
(e.g., UE 120), an eNB (e.g., eNB 110), and/or any other network
entity to facilitate resource coordination. In one example,
resource coordination module 112 can facilitate the generation of
and/or otherwise include a network color graph 612, which can be
utilized in combination with information relating to neighbor node
resources 614 and/or a conflict analyzer 616 to efficiently manage
resources associated with system 600. In accordance with various
aspects, network color graph 612 can be leveraged by resource
coordination module 112 to mitigate effects associated with
non-consensus scenarios resulting from the use of distributed
resource management algorithms.
[0069] In accordance with one aspect, a two-link system can be
considered, wherein transmission of a first link interferes with a
second link such that the two links should not request the same
resource unless both links have a significant amount of data to
transmit. In such a system, resource coordination module 112 can
facilitate basic conflict avoidance through the generation of an
interference graph or network color graph 612. In one example,
respective network nodes represented by network color graph 612 can
be colored such that two nodes connected by an edge do not have the
same color. Such an algorithm can facilitate a resource granularity
of, for example, two multiplied by the degree of network color
graph 612. In one example, distributed algorithms can be utilized
for coloring network color graph 612.
[0070] Based on network color graph 612 and neighbor node resources
614, some or all resources associated with system 600 can be
statically or semi-statically assigned to respective nodes and/or
links in system 600 such that a link operating according to
conflict analyzer 616 can first request resources corresponding to
its own color. If no such resources are available, resources not
belonging to the link's neighbors can be utilized. Next, remaining
resources can be requested in decreasing order of conflict.
[0071] Referring now to FIGS. 7-9, methodologies that can be
performed in accordance with various aspects set forth herein are
illustrated. While, for purposes of simplicity of explanation, the
methodologies are shown and described as a series of acts, it is to
be understood and appreciated that the methodologies are not
limited by the order of acts, as some acts can, in accordance with
one or more aspects, occur in different orders and/or concurrently
with other acts from that shown and described herein. For example,
those skilled in the art will understand and appreciate that a
methodology could alternatively be represented as a series of
interrelated states or events, such as in a state diagram.
Moreover, not all illustrated acts may be required to implement a
methodology in accordance with one or more aspects.
[0072] With reference to FIG. 7, illustrated is a methodology 700
for generating and transmitting signaling for interference
management in a wireless communication system. It is to be
appreciated that methodology 700 can be performed by, for example,
an eNB (e.g., eNB 110), a UE (e.g., UE 120), and/or any other
appropriate network entity. Methodology 700 begins at block 702,
wherein one or more priority parameters (e.g., priority parameters
422) associated with a communication link and a designated set of
resources for communication via the communication link are
identified. Next, at block 704, a RUM is constructed (e.g., by a
reservation request module 122) that includes a request for
reduction of transmit power on the designated set of resources and
a function of the one or more priority parameters identified at
block 702. Methodology 700 can then conclude at block 706, wherein
the RUM constructed at block 704 is communicated to at least one
interfering network node.
[0073] Turning now to FIG. 8, a flow diagram of another methodology
800 for generating and transmitting signaling for interference
management in a wireless communication system is illustrated.
Methodology 800 can be performed by, for example, a wireless
terminal device and/or any other appropriate network entity.
Methodology 800 begins at block 802, wherein a RUM request is
received from a serving network node (e.g., from a serving eNB 410
via a RUM instruction module 412) that relates to a specified set
of resources. At block 804, a RUM is transmitted to an interfering
network node (e.g., interfering eNB 430) that requests power
backoff on the specified set of resources. Next, at block 806,
power decision pilot signaling is received from the interfering
network node in response to the RUM transmitted at block 804.
Finally, at block 808, estimated channel quality relating to the
specified set of resources as determined based on the power
decision pilot signaling to the serving network node received at
block 806 is reported (e.g., via a resource quality reporter
426).
[0074] FIG. 9 illustrates a methodology 900 for processing resource
utilization messaging in association with resource and interference
management for a wireless communication system. Methodology 900 can
be performed by, for example, an eNB, a UE, and/or any other
suitable network entity. Methodology 900 begins at block 902,
wherein respective RUMs are obtained that include one or more
parameters constructed as a function of at least one priority
metric and that request power backoff on a specified set of
resources. Methodology 900 can then conclude at block 904, wherein
an extent of power backoff to be performed on the specified set of
resources included in the RUMs received at block 902 is determined
(e.g., by a utility computation module 432 and/or a power control
module 434) based on the respective RUMs and respective parameters,
such as the one or more parameters constructed as a function of at
least one priority metric, provided within the respective RUMs.
[0075] Referring next to FIGS. 10-11, respective apparatuses
1000-1100 that can be utilized to facilitate various aspects
described herein are illustrated. It is to be appreciated that
apparatuses 1000-1100 are represented as including functional
blocks, which can be functional blocks that represent functions
implemented by a processor, software, or combination thereof (e.g.,
firmware).
[0076] With reference first to FIG. 10, an apparatus 1000 that
facilitates resource coordination and interference management in a
wireless communication network is illustrated. Apparatus 1000 can
be implemented by an eNB (e.g., eNB 110), a UE (e.g., UE 120),
and/or any other suitable network entity and can include a module
1002 for constructing resource utilization messaging that includes
a request for power backoff on a specified set of resources and a
function of at least one priority metric associated with the
specified set of resources and a module 1004 for communicating the
resource utilization messaging to at least one network node from
which interference is observed.
[0077] FIG. 11 illustrates another apparatus 1100 that facilitates
resource coordination and interference management in a wireless
communication network. Apparatus 1100 can be implemented by a Node
B, a terminal, and/or any other suitable network entity and can
include a module 1102 for receiving resource utilization messaging
that includes a request for transmit power reduction on designated
resources and a function of one or more link quality metrics
associated with the designated resources and a module 1104 for
determining an amount of transmit power reduction to be applied on
the designated resources based at least in part on the one or more
parameters constructed as a function of at least one priority
metric provided in the resource utilization messaging.
[0078] FIG. 12 is a block diagram of a system 1200 that can be
utilized to implement various aspects of the functionality
described herein. In one example, system 1200 includes a mobile
terminal 1202. As illustrated, mobile terminal 1202 can receive
signal(s) from one or more base stations 1204 and transmit to the
one or more base stations 1204 via one or more antennas 1208.
Additionally, mobile terminal 1202 can comprise a receiver 1210
that receives information from antenna(s) 1208. In one example,
receiver 1210 can be operatively associated with a demodulator
(Demod) 1212 that demodulates received information. Demodulated
symbols can then be analyzed by a processor 1214. Processor 1214
can be coupled to memory 1216, which can store data and/or program
codes related to mobile terminal 1202. Additionally, mobile
terminal 1202 can employ processor 1214 to perform methodologies
700-900 and/or other similar and appropriate methodologies. Mobile
terminal 1202 can also include a modulator 1218 that can multiplex
a signal for transmission by a transmitter 1220 through antenna(s)
1208.
[0079] FIG. 13 is a block diagram of another system 1300 that can
be utilized to implement various aspects of the functionality
described herein. In one example, system 1300 includes a base
station or Node B 1302. As illustrated, Node B 1302 can receive
signal(s) from one or more UEs 1304 via one or more receive (Rx)
antennas 1306 and transmit to the one or more UEs 1304 via one or
more transmit (Tx) antennas 1308. Additionally, Node B 1302 can
comprise a receiver 1310 that receives information from receive
antenna(s) 1306. In one example, the receiver 1310 can be
operatively associated with a demodulator (Demod) 1312 that
demodulates received information. Demodulated symbols can then be
analyzed by a processor 1314. Processor 1314 can be coupled to
memory 1316, which can store information related to code clusters,
access terminal assignments, lookup tables related thereto, unique
scrambling sequences, and/or other suitable types of information.
Additionally, mobile terminal 1302 can employ processor 1313 to
perform methodology 700, methodology 900, and/or other similar and
appropriate methodologies. Node B 1302 can also include a modulator
1318 that can multiplex a signal for transmission by a transmitter
1320 through transmit antenna(s) 1308.
[0080] Referring now to FIG. 14, an illustration of a wireless
multiple-access communication system is provided in accordance with
various aspects. In one example, an access point 1400 (AP) includes
multiple antenna groups. As illustrated in FIG. 14, one antenna
group can include antennas 1404 and 1406, another can include
antennas 1408 and 1410, and another can include antennas 1412 and
1414. While only two antennas are shown in FIG. 14 for each antenna
group, it should be appreciated that more or fewer antennas may be
utilized for each antenna group. In another example, an access
terminal 1416 can be in communication with antennas 1412 and 1414,
where antennas 1412 and 1414 transmit information to access
terminal 1416 over forward link 1420 and receive information from
access terminal 1416 over reverse link 1418. Additionally and/or
alternatively, access terminal 1422 can be in communication with
antennas 1406 and 1408, where antennas 1406 and 1408 transmit
information to access terminal 1422 over forward link 1426 and
receive information from access terminal 1422 over reverse link
1424. In a frequency division duplex system, communication links
1418, 1420, 1424 and 1426 can use different frequency for
communication. For example, forward link 1420 may use a different
frequency then that used by reverse link 1418.
[0081] Each group of antennas and/or the area in which they are
designed to communicate can be referred to as a sector of the
access point. In accordance with one aspect, antenna groups can be
designed to communicate to access terminals in a sector of areas
covered by access point 1400. In communication over forward links
1420 and 1426, the transmitting antennas of access point 1400 can
utilize beamforming in order to improve the signal-to-noise ratio
of forward links for the different access terminals 1416 and 1422.
Also, an access point using beamforming to transmit to access
terminals scattered randomly through its coverage causes less
interference to access terminals in neighboring cells than an
access point transmitting through a single antenna to all its
access terminals.
[0082] An access point, e.g., access point 1400, can be a fixed
station used for communicating with terminals and can also be
referred to as a base station, an eNB, an access network, and/or
other suitable terminology. In addition, an access terminal, e.g.,
an access terminal 1416 or 1422, can also be referred to as a
mobile terminal, user equipment, a wireless communication device, a
terminal, a wireless terminal, and/or other appropriate
terminology.
[0083] Referring now to FIG. 15, a block diagram illustrating an
example wireless communication system 1500 in which various aspects
described herein can function is provided. In one example, system
1500 is a multiple-input multiple-output (MIMO) system that
includes a transmitter system 1510 and a receiver system 1550. It
should be appreciated, however, that transmitter system 1510 and/or
receiver system 1550 could also be applied to a multi-input
single-output system wherein, for example, multiple transmit
antennas (e.g., on a base station), can transmit one or more symbol
streams to a single antenna device (e.g., a mobile station).
Additionally, it should be appreciated that aspects of transmitter
system 1510 and/or receiver system 1550 described herein could be
utilized in connection with a single output to single input antenna
system.
[0084] In accordance with one aspect, traffic data for a number of
data streams are provided at transmitter system 1510 from a data
source 1512 to a transmit (TX) data processor 1514. In one example,
each data stream can then be transmitted via a respective transmit
antenna 1524. Additionally, TX data processor 1514 can format,
encode, and interleave traffic data for each data stream based on a
particular coding scheme selected for each respective data stream
in order to provide coded data. In one example, the coded data for
each data stream can then be multiplexed with pilot data using OFDM
techniques. The pilot data can be, for example, a known data
pattern that is processed in a known manner. Further, the pilot
data can be used at receiver system 1550 to estimate channel
response. Back at transmitter system 1510, the multiplexed pilot
and coded data for each data stream can be modulated (e.g., symbol
mapped) based on a particular modulation scheme (e.g., BPSK, QSPK,
M-PSK, or M-QAM) selected for each respective data stream in order
to provide modulation symbols. In one example, data rate, coding,
and modulation for each data stream can be determined by
instructions performed on and/or provided by processor 1530.
[0085] Next, modulation symbols for all data streams can be
provided to a TX MIMO processor 1520, which can further process the
modulation symbols (e.g., for OFDM). TX MIMO processor 1520 can
then provides N.sub.T modulation symbol streams to N.sub.T
transceivers 1522a through 1522t. In one example, each transceiver
1522 can receive and process a respective symbol stream to provide
one or more analog signals. Each transceiver 1522 can then further
condition (e.g., amplify, filter, and upconvert) the analog signals
to provide a modulated signal suitable for transmission over a MIMO
channel. Accordingly, N.sub.T modulated signals from transceivers
1522a through 1522t can then be transmitted from N.sub.T antennas
1524a through 1524t, respectively.
[0086] In accordance with another aspect, the transmitted modulated
signals can be received at receiver system 1550 by N.sub.R antennas
1552a through 1552r. The received signal from each antenna 1552 can
then be provided to respective transceivers 1554. In one example,
each transceiver 1554 can condition (e.g., filter, amplify, and
downconvert) a respective received signal, digitize the conditioned
signal to provide samples, and then processes the samples to
provide a corresponding "received" symbol stream. An RX MIMO/data
processor 1560 can then receive and process the N.sub.R received
symbol streams from N.sub.R transceivers 1554 based on a particular
receiver processing technique to provide N.sub.T "detected" symbol
streams. In one example, each detected symbol stream can include
symbols that are estimates of the modulation symbols transmitted
for the corresponding data stream. RX processor 1560 can then
process each symbol stream at least in part by demodulating,
deinterleaving, and decoding each detected symbol stream to recover
traffic data for a corresponding data stream. Thus, the processing
by RX processor 1560 can be complementary to that performed by TX
MIMO processor 1520 and TX data processor 1514 at transmitter
system 1510. RX processor 1560 can additionally provide processed
symbol streams to a data sink 1564.
[0087] In accordance with one aspect, the channel response estimate
generated by RX processor 1560 can be used to perform space/time
processing at the receiver, adjust power levels, change modulation
rates or schemes, and/or other appropriate actions. Additionally,
RX processor 1560 can further estimate channel characteristics such
as, for example, signal-to-noise-and-interference ratios (SNRs) of
the detected symbol streams. RX processor 1560 can then provide
estimated channel characteristics to a processor 1570. In one
example, RX processor 1560 and/or processor 1570 can further derive
an estimate of the "operating" SNR for the system. Processor 1570
can then provide channel state information (CSI), which can
comprise information regarding the communication link and/or the
received data stream. This information can include, for example,
the operating SNR. The CSI can then be processed by a TX data
processor 1518, modulated by a modulator 1580, conditioned by
transceivers 1554a through 1554r, and transmitted back to
transmitter system 1510. In addition, a data source 1516 at
receiver system 1550 can provide additional data to be processed by
TX data processor 1518.
[0088] Back at transmitter system 1510, the modulated signals from
receiver system 1550 can then be received by antennas 1524,
conditioned by transceivers 1522, demodulated by a demodulator
1540, and processed by a RX data processor 1542 to recover the CSI
reported by receiver system 1550. In one example, the reported CSI
can then be provided to processor 1530 and used to determine data
rates as well as coding and modulation schemes to be used for one
or more data streams. The determined coding and modulation schemes
can then be provided to transceivers 1522 for quantization and/or
use in later transmissions to receiver system 1550. Additionally
and/or alternatively, the reported CSI can be used by processor
1530 to generate various controls for TX data processor 1514 and TX
MIMO processor 1520. In another example, CSI and/or other
information processed by RX data processor 1542 can be provided to
a data sink 1544.
[0089] In one example, processor 1530 at transmitter system 1510
and processor 1570 at receiver system 1550 direct operation at
their respective systems. Additionally, memory 1532 at transmitter
system 1510 and memory 1572 at receiver system 1550 can provide
storage for program codes and data used by processors 1530 and
1570, respectively. Further, at receiver system 1550, various
processing techniques can be used to process the N.sub.R received
signals to detect the N.sub.T transmitted symbol streams. These
receiver processing techniques can include spatial and space-time
receiver processing techniques, which can also be referred to as
equalization techniques, and/or "successive nulling/equalization
and interference cancellation" receiver processing techniques,
which can also be referred to as "successive interference
cancellation" or "successive cancellation" receiver processing
techniques.
[0090] It is to be understood that the aspects described herein can
be implemented by hardware, software, firmware, middleware,
microcode, or any combination thereof. When the systems and/or
methods are implemented in software, firmware, middleware or
microcode, program code or code segments, they can be stored in a
machine-readable medium, such as a storage component. A code
segment can represent a procedure, a function, a subprogram, a
program, a routine, a subroutine, a module, a software package, a
class, or any combination of instructions, data structures, or
program statements. A code segment can be coupled to another code
segment or a hardware circuit by passing and/or receiving
information, data, arguments, parameters, or memory contents.
Information, arguments, parameters, data, etc. can be passed,
forwarded, or transmitted using any suitable means including memory
sharing, message passing, token passing, network transmission,
etc.
[0091] For a software implementation, the techniques described
herein can be implemented with modules (e.g., procedures,
functions, and so on) that perform the functions described herein.
The software codes can be stored in memory units and executed by
processors. The memory unit can be implemented within the processor
or external to the processor, in which case it can be
communicatively coupled to the processor via various means as is
known in the art.
What has been described above includes examples of one or more
aspects. It is, of course, not possible to describe every
conceivable combination of components or methodologies for purposes
of describing the aforementioned aspects, but one of ordinary skill
in the art can recognize that many further combinations and
permutations of various aspects are possible. Accordingly, the
described aspects are intended to embrace all such alterations,
modifications and variations that fall within the spirit and scope
of the appended claims. Furthermore, to the extent that the term
"includes" is used in either the detailed description or the
claims, such term is intended to be inclusive in a manner similar
to the term "comprising" as "comprising" is interpreted when
employed as a transitional word in a claim. Furthermore, the term
"or" as used in either the detailed description or the claims is
meant to be a "non-exclusive or."
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