U.S. patent application number 13/221583 was filed with the patent office on 2011-12-22 for system and method for autonomous combining.
This patent application is currently assigned to RESEARCH IN MOTION LIMITED. Invention is credited to Zhijun Cai, James Earl Womack, Yi Yu.
Application Number | 20110310912 13/221583 |
Document ID | / |
Family ID | 41567265 |
Filed Date | 2011-12-22 |
United States Patent
Application |
20110310912 |
Kind Code |
A1 |
Cai; Zhijun ; et
al. |
December 22, 2011 |
System and Method For Autonomous Combining
Abstract
A user agent capable of autonomous combining. The user agent can
be implemented as a processor configured to promote receiving a
first signal from an access node and a second signal from a relay
node. The processor may be further configured to combine the first
and second signals.
Inventors: |
Cai; Zhijun; (Euless,
TX) ; Womack; James Earl; (Bedford, TX) ; Yu;
Yi; (Irving, TX) |
Assignee: |
RESEARCH IN MOTION LIMITED
Waterloo
CA
|
Family ID: |
41567265 |
Appl. No.: |
13/221583 |
Filed: |
August 30, 2011 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
12337214 |
Dec 17, 2008 |
8040904 |
|
|
13221583 |
|
|
|
|
Current U.S.
Class: |
370/476 |
Current CPC
Class: |
H04B 7/022 20130101;
H04B 7/026 20130101 |
Class at
Publication: |
370/476 |
International
Class: |
H04J 3/00 20060101
H04J003/00 |
Claims
1. A user agent, comprising: a processor configured to promote
receiving a first signal from an access node and a second signal
from a relay node, the processor further configured to combine the
first and second signals.
2. The user agent of claim 1, wherein the first and second signals
are further defined as first and second transmissions,
respectively, containing a first and second data, respectively.
3. The user agent of claim 2 wherein the second transmission is
received a first time after the first transmission, and wherein the
user agent is further configured to: combine the first and second
data after the user agent waits for a second time that is at least
as long as the first time.
4. The user agent of claim 2 wherein combining is facilitated by
the user agent receiving additional data in a control channel.
5. The user agent of claim 4 wherein the additional data indicates
to the user agent, before receipt of the second transmission, that
the first and second data are substantially similar.
6. The user agent of claim 4 wherein the additional data comprises
a particular set of addresses from among a plurality of sets of
addresses, and wherein the particular set of addresses includes a
first subset of addresses that identify a corresponding relay node
that can provide service for the user agent, and wherein the
particular set of addresses includes a second subset of addresses
that identify the user agent.
7. The user agent of claim 2 wherein the user agent is further
configured to: disable a function that allows the first and second
data to be combined.
8. The user agent of claim 7 wherein the user agent is further
configured to: disable the function responsive to a failure to
receive the first transmission.
9. The user agent of claim 7 wherein the user agent is further
configured to: disable the function responsive to the first
transmission having a weak signal to interference plus noise ratio
(SINR).
10. The user agent of claim 9 wherein the user agent is further
configured to: re-enable the function responsive to the first
transmission.
11. The user agent of claim 2 wherein the processor is configured
to combine the first and second data using either incremental
redundancy combining or chase combining.
12. A method implemented in a user agent, the method comprising:
receiving a first signal from an access node; receiving a second
signal from a relay node, and combining the first and second
signals.
13. The method of claim 12, wherein the first and second signals
are further defined as first and second transmissions,
respectively, containing a first and second data, respectively.
14. The method of claim 13 wherein the second transmission is
received a first time after the first transmission, and wherein the
method further comprises: combining the first and second data after
the user agent waits for a second time that is at least as long as
the first time.
15. The method of claim 13 wherein combining is facilitated by the
user agent receiving additional data in a control channel.
16. The method of claim 15 wherein the additional data comprises a
particular set of addresses from among a plurality of sets of
addresses, and wherein the particular set of addresses includes a
first subset of addresses that identify a corresponding relay node
that can provide service for the user agent, and wherein the
particular set of addresses includes a second subset of addresses
that identify the user agent.
Description
[0001] This application is a continuation of U.S. patent
application Ser. No. 12/337,214 filed on Dec. 17, 2008, and
entitled "System and Method for Autonomous Combining,"
(34656-US-PAT-4214-14400) which is incorporated herein by reference
as if reproduced in its entirety.
BACKGROUND
[0002] As used herein, the terms "user agent" and "UA" might in
some cases refer to mobile devices such as mobile telephones,
personal digital assistants, handheld or laptop computers, and
similar devices that have telecommunications capabilities. Such a
UA might consist of a UA and its associated removable memory
module, such as but not limited to a Universal Integrated Circuit
Card (UICC) that includes a Subscriber Identity Module (SIM)
application, a Universal Subscriber Identity Module (USIM)
application, or a Removable User Identity Module (R-UIM)
application. Alternatively, such a UA might consist of the device
itself without such a module. In other cases, the term "UA" might
refer to devices that have similar capabilities but that are not
transportable, such as desktop computers, set-top boxes, or network
appliances. The term "UA" can also refer to any hardware or
software component that can terminate a communication session for a
user. Also, the terms "user agent," "UA," "user equipment," "UE,"
"user device" and "user node" might be used synonymously
herein.
[0003] As telecommunications technology has evolved, more advanced
network access equipment has been introduced that can provide
services that were not possible previously. This network access
equipment might include systems and devices that are improvements
of the equivalent equipment in a traditional wireless
telecommunications system. Such advanced or next generation
equipment may be included in evolving wireless communications
standards, such as long-term evolution (LTE). For example, an LTE
system might include an enhanced node B (eNB), a wireless access
point, or a similar component rather than a traditional base
station. As used herein, the term "access node" will refer to any
component of the wireless network, such as a traditional base
station, a wireless access point, or an LTE eNB, that creates a
geographical area of reception and transmission coverage allowing a
UA or a relay node to access other components in a
telecommunications system. In this document, the term "access node"
and "access node" may be used interchangeably, but it is understood
that an access node may comprise a plurality of hardware and
software.
[0004] The term "access node" does not refer to a "relay node,"
which is a component in a wireless network that is configured to
extend or enhance the coverage created by an access node or another
relay node. The access node and relay node are both radio
components that may be present in a wireless communications
network, and the terms "component" and "network node" may refer to
an access node or relay node. It is understood that a component
might operate as an access node or a relay node depending on its
configuration and placement. However, a component is called a
"relay node" only if it requires the wireless coverage of an access
node to access other components in a wireless communications
system. Additionally, two or more relay nodes may used serially to
extend or enhance coverage created by an access node.
[0005] An LTE system can include protocols such as a Radio Resource
Control (RRC) protocol, which is responsible for the assignment,
configuration, and release of radio resources between a UA and a
network node or other LTE equipment. The RRC protocol is described
in detail in the Third Generation Partnership Project (3GPP)
Technical Specification (TS) 36.331. According to the RRC protocol,
the two basic RRC modes for a UA are defined as "idle mode" and
"connected mode." During the connected mode or state, the UA may
exchange signals with the network and perform other related
operations, while during the idle mode or state, the UA may shut
down at least some of its connected mode operations. Idle and
connected mode behaviors are described in detail in 3GPP TS 36.304
and TS 36.331.
[0006] The signals that carry data between UAs, relay nodes, and
access nodes can have frequency, time, and coding parameters and
other characteristics that might be specified by a network node. A
connection between any of these elements that has a specific set of
such characteristics can be referred to as a resource. The terms
"resource," "communications connection," "channel," and
"communications link" might be used synonymously herein. A network
node typically establishes a different resource for each UA or
other network node with which it is communicating at any particular
time.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] For a more complete understanding of this disclosure,
reference is now made to the following brief description, taken in
connection with the accompanying drawings and detailed description,
wherein like reference numerals represent like parts.
[0008] FIG. 1 is a diagram illustrating a wireless communication
system that includes a relay node, according to an embodiment of
the disclosure.
[0009] FIG. 2 is a block diagram of a relay node in communication
with an access node and a user agent, according to an embodiment of
the disclosure.
[0010] FIG. 3A is a flowchart illustrating a method of autonomous
combining in a user agent, according to an embodiment of the
disclosure.
[0011] FIG. 3B is a flowchart illustrating a method in an access
node for facilitating autonomous combining in a user agent,
according to an embodiment of the disclosure.
[0012] FIG. 4 illustrates a processor and related components
suitable for implementing the several embodiments of the present
disclosure.
DETAILED DESCRIPTION
[0013] It should be understood at the outset that although
illustrative implementations of one or more embodiments of the
present disclosure are provided below, the disclosed systems and/or
methods may be implemented using any number of techniques, whether
currently known or in existence. The disclosure should in no way be
limited to the illustrative implementations, drawings, and
techniques illustrated below, including the exemplary designs and
implementations illustrated and described herein, but may be
modified within the scope of the appended claims along with their
full scope of equivalents.
[0014] FIG. 1 is a diagram illustrating a wireless communication
system 100 using a relay node 102, according to an embodiment of
the disclosure. Generally, the present disclosure relates to the
use of relay nodes in wireless communications networks. Examples of
wireless communication networks include LTE or LTE-Advanced (LTE-A)
networks, and all of the disclosed and claimed embodiments could be
implemented in an LTE-A network. The relay node 102 can amplify or
repeat a signal received from a UA 110 and cause the modified
signal to be received at an access node 106. In some
implementations of a relay node 102, the relay node 102 receives a
signal with data from the UA 110 and then generates a new signal to
transmit the data to the access node 106. The relay node 102 can
also receive data from the access node 106 and deliver the data to
the UA 110. The relay node 102 might be placed near the edges of a
cell so that the UA 110 can communicate with the relay node 102
rather than communicating directly with the access node 106 for
that cell.
[0015] In radio systems, a cell is a geographical area of reception
and transmission coverage. Cells can overlap with each other. In
the typical example, there is one access node associated with each
cell. The size of a cell is determined by factors such as frequency
band, power level, and channel conditions. Relay nodes, such as
relay node 102, can be used to enhance coverage within or near a
cell, or to extend the size of coverage of a cell. Additionally,
the use of a relay node 102 can enhance throughput of a signal
within a cell because the UA 110 can access the relay node 102 at a
higher data rate or a lower power transmission than the UA 110
might use when communicating directly with the access node 106 for
that cell. Transmission at a higher data rate creates higher
spectrum efficiency, and lower power benefits the UA 110 by
consuming less battery power.
[0016] Relay nodes, generally, can be divided into three types:
layer one relay nodes, layer two relay nodes, and layer three relay
nodes. A layer one relay node is essentially a repeater that can
retransmit a transmission without any modification other than
amplification and slight delay. A layer two relay node can decode a
transmission that it receives, re-encode the result of the
decoding, and then transmit the re-encoded data. A layer three
relay node can have full radio resource control capabilities and
can thus function similarly to an access node. The radio resource
control protocols used by a relay node may be the same as those
used by an access node, and the relay node may have a unique cell
identity typically used by an access node. For the purpose of this
disclosure, a relay node is distinguished from an access node by
the fact that it requires the presence of at least one access node
(and the cell associated with that access node) to access other
components in a telecommunications system. The illustrative
embodiments are primarily concerned with layer two or layer three
relay nodes. Therefore, as used herein, the term "relay node" will
not refer to layer one relay nodes, unless specifically stated
otherwise.
[0017] In communication system 100, the links that allow wireless
communication can be said to be of three distinct types. First,
when the UA 110 is communicating with the access node 106 via the
relay node 102, the communication link between the UA 110 and the
relay node 102 is said to occur over an access link 108. Second,
the communication between the relay node 102 and the access node
106 is said to occur over a relay link 104. Third, communication
that passes directly between the UA 110 and the access node 106
without passing through the relay node 102 is said to occur over a
direct link 112. The terms "access link," "relay link," and "direct
link" are used in this document according to the meaning described
by FIG. 1.
[0018] In wireless communications, any device capable of receiving
wireless signals potentially could be configured to process a
received wireless signal. For example, an access node transmits a
first signal that contains first data. That first signal can be
received by both a UA and a relay node to which the UA is
connected. In turn, the relay node may generate and transmit a
second signal to the UA that contains substantially similar data;
however, the second signal may likely be transmitted using a
different modulation and coding scheme relative to the first
signal. The UA can thereby receive substantially the same data from
both the first signal (from the access node) and then, a short time
later, from the second signal (from the relay node). Although two
different signals are actually used (one from the access node and
one from the relay node), both signals may convey substantially the
same data. Although the data from the access node and the relay
node may be referred to as transmitting substantially the same data
that is received by the UA, it will be appreciated that there may
be some differences, and so the related data received by the UA in
this instance may not be exactly the same.
[0019] Because the UA can receive substantially the same data from
different signals transmitted by the access node and the relay
node, before decoding the data, an opportunity arises to combine
the demodulated data received from the two different signals or,
possibly if the modulation and coding schemes of the two signals
are substantially similar, to combine the signals before
demodulating the data. By combining the data from the two signals,
the UA can potentially improve data reception and thereby may allow
the UA to better convey a service or otherwise improve
performance.
[0020] Thus, the illustrative embodiments provide for a user agent
capable of autonomous combining. The user agent can be implemented
as a processor configured to promote receiving a first signal from
an access node and a second signal from a relay node. The processor
may be further configured to combine the first and second
signals.
[0021] FIG. 2 is a block diagram of a relay node 200 in
communication with an access node 202 and a UA 204, according to an
embodiment of the disclosure. These devices are similar to, and
operate in a manner similar to, corresponding devices in FIG. 1.
Thus, for example, relay node 200 could be relay node 102 in FIG.
1, access node 202 could be access node 106 in FIG. 1, and UA 204
could be UA 110 in FIG. 1.
[0022] Relay node 200 operates within relay node cell 206.
Likewise, access node 202 operates within access node cell 207. For
purposes of the embodiments described herein, UA 204 is within the
boundaries of both relay node cell 206 and access node cell 207.
Likewise, relay node 200 is within access node cell 207. However,
potentially, UA 204 could be within only one of relay node cell 206
or access node cell 207, or possibly within some other cell, and
still receive service. For purposes of the embodiments described
herein, the elliptical lines representing relay node cell 206 and
access node cell 207 represent conceptual boundaries only, and do
not necessarily represent the actual boundaries of these cells.
[0023] Because UA 204 is within relay node cell 206 and access node
cell 207, UA 204 might receive signals from both relay node 200 and
access node 202. Thus, due to propagation characteristics of
wireless channels, substantially the same data could be transmitted
to UA 204 by both relay node 200 and access node 202.
[0024] For example, access node 202 may send out a first signal
that conveys data, as shown by both of arrows 210. The first signal
is intended primarily for the relay node 200, but may be strong
enough to be detected by the UA 204. Thus, arrows 210 show that, in
one embodiment, the same signal (the first signal) is received by
both relay node 200 and UA 204.
[0025] Thereafter, relay node 200 may relay or transmit a second
signal (as shown by arrow 212) to UA 204. The second signal may
convey substantially the same data contained in the first signal
that had been transmitted from the access node 202. Thus, UA 204
receives the first signal (arrow 210) and a short time later
receives the second signal (arrow 212), with both signals conveying
substantially the same data.
[0026] The fact that UA 204 receives the same data from two
different sources creates an opportunity for autonomous combining.
In autonomous combining, the two different signals (via the relay
link from the access node 202 and via the access link from the
relay node 200) are demodulated at the UA 204, and the respective
coded bits from each signal are combined. In this manner, the
ultimate data decoded by UA 204 is more likely to accurately
reflect the original data, such as was first transmitted from the
access node 202. As a result, UA 204 can convey better service
quality, or otherwise improve performance.
[0027] In another embodiment, the modulation and coding schemes of
the two signals are substantially the same and the two different
signals can be combined before demodulation. Alternatively, when
the UA 204 receives a signal from the access link, the UA 204 will
attempt to demodulate and decode the signal. If the reception is
successful, the UA 204 may ignore the second signal. Otherwise,
autonomous combining will proceed.
[0028] For example, during poor or varying channel conditions, the
UA 204 may not be able to accurately demodulate and decode portions
of first data conveyed along the relay link from the access node
202 to the UA 204. Likewise, second data conveyed along the access
link (arrow 212) may be difficult to demodulate and decode for
similar or other reasons. While in some instances the first data
received via the relay link is supposed to be substantially the
same as the second data received via the access link, the poor
channel conditions may result in differences between the first data
and the second data. However, if UA 204 demodulates and combines
both the first and second signals, and then decodes, performance
may be improved.
[0029] In different embodiments, combining data can be performed by
a number of different methods. In one embodiment, incremental
redundancy combining can be used. In incremental redundancy
combining, coded bits are combined together based on the
incremental redundancy parameter before the actual decoding. The
incremental redundancy parameter is signaled to the UA 204 via the
control channel. In another embodiment, blind decoding can be used.
During blind decoding, the UA 204 demodulates and decodes signals
as they arrive, without regard to coordinating signals. If the
decoding is unsuccessful, and when a second signal bearing
substantially similar data arrives, the UA 204 will attempt to
combine the data before the decoding. However, little information
is given to the UA 204 to perform the combining. This method may
use more battery power in the UA 204. While the embodiments have
disclosed two methods of combining, other methods of combining data
could be used as well.
[0030] The modulation and coding scheme (MCS) of the signal on the
access link (arrow 212) may be different than the MCS of the signal
on the relay link (arrow 210). Thus, the UA may demodulate each
signal and then combine the data, which may be channel encoded data
received from each signal, as described above. In the event the MCS
of the signals on both the access link and the relay link are the
same or substantially similar, the two signals could be combined
directly before demodulation in order to increase signal quality.
The combined signal could then be decoded. Various other
alternatives for combining the signals and/or data will readily
suggest themselves and are within the scope of the present
disclosure and claims.
[0031] The embodiments described above contemplate two, possibly
more, signals being received: one on the access link, one on the
relay link, and possibly more signals received from other relay
nodes or access nodes. Thus, for example, signals received via
multiple relay nodes and/or multiple access nodes could be
received, decoded, with the resulting corresponding data streams
being combined. However, if only one transmission is received, then
the single transmission may still be considered successful.
[0032] Regarding acknowledgement/non-acknowledgement signals,
because the UA 204 uses the access link (arrow 212) primarily for
communication, the UA 204 only sends the ACK/NACK to the relay node
200. No ACK/NACK is sent from the UA 204 directly to the access
node 202. For example, if the UA 204 decodes the combined data
successfully, the UA 204 will send the ACK to the relay node.
Accordingly, the relay node 202 may perform HARQ retransmissions.
HARQ retransmissions could also be autonomously combined with
signals from the relay link (arrow 210).
[0033] In a different embodiment, the UA 204 may receive a signal
from the access node 202, wait for a short time, (represented by
combined subframes) and then receive the same signal from the relay
node 200. At that time or later, the UA 204 decodes the two signals
and then combines the respective data contained in the two
signals.
[0034] For example, the access node 202 sends a transport block to
the relay node 200 in subframe "N." Both the UA 204 and the relay
node 200 receive the subframe. No
non-acknowledgement/acknowledgement (NACK/ACK) signal may be
transmitted from the UA 204 to the access node 202; though a
NACK/ACK signal is transmitted from the relay node 200 to the
access node 202.
[0035] The UA 204 will attempt to decode the transmission from the
access node 202. Decoding requires that the UA 204 monitor the
physical downlink control channel (PDCCH) of the relay link.
Optionally, the UA 204 can perform error correction. The relay node
200 schedules the received transport block for transmission to the
UA 204 on subframe "N"+"M," wherein "M" is a relatively small
number. The relay node 200 schedules the received transport block
on the access link PDCCH in the same manner as the access node 202
did on the relay link. The UA may then wait for "M" subframes, more
or less, to receive the transmission from the relay node 200. At
that point, the UA may demodulate the separate signals and then
implement autonomous combining of the resulting data, as described
above.
[0036] In another embodiment, the access node 202 uses the
identification (ID) of the UA 204 to deliver the scheduling grant
to the relay node 200. The scheduling grant indicates to the relay
node 200 that data for the UA 204 is being sent.
[0037] Because the access node 202 delivers the scheduling grant to
the relay node 200 using the ID of the UA 204, the signal conveyed
by the access link (arrow 212) and the relay link (arrow 210) can
be identified for receipt by the UA 204. Further, additional data
may be coded in a control channel (such as the PDCCH), with the
additional data allowing a UA to know that the UA will receive
substantially duplicate data over both the access link and the
relay link. Thus, the UA 204 may anticipate reception of
substantially duplicate data conveyed over coordinated signals.
When the UA 204 receives the two signals, the UA 204 can perform
autonomous combining, as described above. Accordingly, the
scheduling grant by the access node 202 can be used to facilitate
more efficient autonomous combining.
[0038] In still another embodiment, the access node 202 reserves a
set of addresses for each relay node 200 in the cell serviced by
access node 202. In one example, the access node 202 may divide the
set of addresses into eight sets, one set for each of eight relay
nodes. For each set, the first three bits of the cell radio network
temporary identifier (C-RNTI) may be designated to each of the
eight relay nodes in the cell of access node 202. Thus, each member
of the set contains three bits to designate a corresponding relay
node. For each member of the set of addresses, all bits following
the first three bits may be used to provide identifiers for UAs.
Thus, any given address identifier identifies the particular relay
node and the particular UA.
[0039] In this manner, a given UA will know the identification of
its relay node, as well as the identification of the UA itself. The
combined identification could be used on both the access link and
relay link. When a combined identification is used, UA 204 may know
that it will receive substantially the same data from two different
signals. When the two signals are received, UA 204 may demodulate
those signals and thereafter combine the data, as provided above.
This technique relieves the need for the relay node 200 to track
identifications of UAs and may present a more flexible
solution.
[0040] In still another embodiment, the access node 202 may promote
the same medium access control packet data unit (MAC PDU) to be
sent several times via the relay link (arrow 212) due to HARQ
retransmission. Assuming incremental redundancy (IR) is used for
the retransmission over the relay link, the UA 204 can also use
incremental redundancy for combining the received data from both
the relay link and the access link in order to obtain better
reception. In this embodiment, the access node 202 may send a
different redundancy version of the data over the relay link 210 as
the relay node would send over the access link 212. The relay node
200 would successfully receive the MAC PDU, re-encode it and send a
different IR version of the re-encoded MAC PDU. The relay node 200
would indicate the version number within the PDCCH scheduling grant
to the UA 204. Additionally, the UA 204 could monitor for
retransmissions from the access node 202 to the relay node 200 over
the relay link 210. The UA 204 will know the version of the data
from the redundancy version signaled in the PDCCH over the relay
link 210.
[0041] In yet another embodiment, a new field may be added over the
PDCCH signaling to identify the received MAC PDU index for
appropriate autonomous combining. This new field on the PDCCH
applies to both the relay link and the access link. The new field
is used to identify the signals containing substantially the same
data transmitted over the relay link or access link. For example, a
3 bit field is added to the PDCCH. When the access node 202 sends
the first MAC PDU over the relay link to a relay node 200 using the
UA's ID, this field is set to "000". Once the relay node forwards
the same MAC PDU to the UA 204, the same value "000" is used in
this field. Therefore, the UA 204 can use this field to identify
the signal that potentially can be combined. The retransmissions of
the same MAC PDU will have the same value "000," so the UA 204 can
identify the potential signal for combining.
[0042] In other embodiments, an individual UA may disable or enable
the use of autonomous combining. Alternatively, autonomous
combining may be disabled for all UAs within a given cell. The
latter case can be implemented by issuing a command from either
relay node 200 or access node 202 to all UAs serviced by the
corresponding device. In yet another illustrative embodiment, a UA
may request that autonomous combining be disabled by either of
relay node 200 or access node 202.
[0043] One reason to disable autonomous combining may be to save
battery power in the UA. Another reason to disable autonomous
combining is where the UA is in a location that has a poor
reception from either one of the relay node 200 or access node 202,
particularly if the access link (arrow 210) does not have good
reception.
[0044] Some UAs in a cell may enable autonomous combining, while
some may not. For UAs that enable the feature, the access node 202
may use UA identifications to deliver the scheduling grant, as well
as other layer one information (such as MCS) to the relay nodes, so
that a UA can detect the scheduling grant. For the UAs that do not
enable autonomous combining, the access node 202 may still use a
single relay node identification to deliver the scheduling
grant.
[0045] In an embodiment, the UA 204 may either autonomously, or by
command of the system, sample the direct link (arrow 210) to
determine if there are any transmissions intended for the UA 204.
To save battery power, the UA 204 might enable autonomous combining
only if the UA 204 receives both direct link signals and relay link
signals.
[0046] In another embodiment, an assumption is made that the PDCCH
on the relay link (arrow 210) is sufficient for reception. However,
this assumption may not always be valid. The UA 204 may attempt to
receive the relay link PDCCH. If the UA 204 receives the relay link
PDCCH, the UA 204 should attempt to decode the intended
transmission. If the attempt fails, the UA 204 can stop trying to
decode, thereby saving battery power. If the UA 204 cannot receive
the PDCCH, the UA 204 may try again after a certain time. Due to
possible improved signal reception, receipt of the PDCCH may be
successful after the certain time.
[0047] A possible benefit to using autonomous combining is that
both the block error rate (BLER) performance and spectrum
efficiency can be improved. Another possible benefit is that data
reception improves, resulting in improved quality of a desired
service and/or other benefits.
[0048] FIG. 3A is a flowchart illustrating a method of autonomous
combining in a UA, according to an embodiment of the disclosure.
Examples of UAs in which the process shown in FIG. 3A can be
implemented include UA 110 of FIG. 1 and UA 204 of FIG. 2.
[0049] The process begins as the UA receives a first signal from an
access node (block 300A). The UA also receives a second signal from
a relay node (block 302A). The UA then combines the first and
second signals (block 304A). The process terminates thereafter.
[0050] In an embodiment, the first and second signals are further
defined as first and second transmissions, respectively, containing
a first and second data, respectively. In this case, combining the
signals is further defined as demodulating portions of the first
and second transmissions and combining the portions of the first
and second data.
[0051] In another embodiment, the second transmission is received a
first time after the first transmission. In this case, combining
the first and second data occurs after the UA waits for a second
time that is at least as long as the first time.
[0052] In yet another embodiment, combining is facilitated by the
UA receiving additional data coded in a control channel. For
example, the additional data could be a particular set of addresses
from among a plurality of sets of addresses. The particular set of
addresses includes a first subset of addresses that identify a
corresponding relay node that can provide service for the UA. The
particular set of addresses also may include a second subset of
addresses that identify the UA.
[0053] In still another embodiment, the UA could be further
configured to disable a function that allows the first and second
data to be combined. The UA could disable the function responsive
to a failure to receive the first transmission within a particular
time. The UA could disable the function responsive to the first
transmission having a weak strength relative to a desired signal
strength. The UA could be further configured to re-enable the
function responsive to the first transmission improving.
[0054] In another embodiment, the first and second data are
combined using incremental redundancy combining. Alternatively, the
first and second data are decoded using blind decoding.
[0055] FIG. 3B is a flowchart illustrating a method in an access
node for facilitating autonomous combining in a UA, according to an
embodiment of the disclosure. Examples of access nodes in which the
process of FIG. 3B could be implemented include access node 106 of
FIG. 1 and access node 202 of FIG. 2.
[0056] The process begins as the access node provides an address
indicating one of a plurality of relay nodes and further indicating
one of a plurality of UAs (block 300B). The access node transmits
the address to one or more of the plurality of relay nodes (block
302B). The access node then transmits a signal to a particular UA
to cause the particular UA to either enable or disable autonomous
combining (block 304B). The process terminates thereafter.
[0057] In an embodiment, the address comprises a first set of bits
and a second set of bits. The first set of bits identifies a
corresponding relay node and the second set of bits identifies a
corresponding UA within a donor cell of the corresponding relay
node.
[0058] The UA 110 and other components described above might
include a processing component that is capable of executing
instructions related to the actions described above. FIG. 4
illustrates an example of a system 1300 that includes a processing
component 1310 suitable for implementing one or more embodiments
disclosed herein. In addition to the processor 1310 (which may be
referred to as a central processor unit or CPU), the system 1300
might include network connectivity devices 1320, random access
memory (RAM) 1330, read only memory (ROM) 1340, secondary storage
1350, and input/output (I/O) devices 1360. These components might
communicate with one another via a bus 1370. In some cases, some of
these components may not be present or may be combined in various
combinations with one another or with other components not shown.
These components might be located in a single physical entity or in
more than one physical entity. Any actions described herein as
being taken by the processor 1310 might be taken by the processor
1310 alone or by the processor 1310 in conjunction with one or more
components shown or not shown in the drawing, such as a digital
signal processor (DSP) 1302. Although the DSP 1302 is shown as a
separate component, the DSP 1302 might be incorporated into the
processor 1310.
[0059] The processor 1310 executes instructions, codes, computer
programs, or scripts that it might access from the network
connectivity devices 1320, RAM 1330, ROM 1340, or secondary storage
1350 (which might include various disk-based systems such as hard
disk, floppy disk, or optical disk). While only one CPU 1310 is
shown, multiple processors may be present. Thus, while instructions
may be discussed as being executed by a processor, the instructions
may be executed simultaneously, serially, or otherwise by one or
multiple processors. The processor 1310 may be implemented as one
or more CPU chips.
[0060] The network connectivity devices 1320 may take the form of
modems, modem banks, Ethernet devices, universal serial bus (USB)
interface devices, serial interfaces, token ring devices, fiber
distributed data interface (FDDI) devices, wireless local area
network (WLAN) devices, radio transceiver devices such as code
division multiple access (CDMA) devices, global system for mobile
communications (GSM) radio transceiver devices, worldwide
interoperability for microwave access (WiMAX) devices, and/or other
well-known devices for connecting to networks. These network
connectivity devices 1320 may enable the processor 1310 to
communicate with the Internet or one or more telecommunications
networks or other networks from which the processor 1310 might
receive information or to which the processor 1310 might output
information. The network connectivity devices 1320 might also
include one or more transceiver components 1325 capable of
transmitting and/or receiving data wirelessly.
[0061] The RAM 1330 might be used to store volatile data and
perhaps to store instructions that are executed by the processor
1310. The ROM 1340 is a non-volatile memory device that typically
has a smaller memory capacity than the memory capacity of the
secondary storage 1350. ROM 1340 might be used to store
instructions and perhaps data that are read during execution of the
instructions. Access to both RAM 1330 and ROM 1340 is typically
faster than to secondary storage 1350. The secondary storage 1350
is typically comprised of one or more disk drives or tape drives
and might be used for non-volatile storage of data or as an
over-flow data storage device if RAM 1330 is not large enough to
hold all working data. Secondary storage 1350 may be used to store
programs that are loaded into RAM 1330 when such programs are
selected for execution.
[0062] The I/O devices 1360 may include liquid crystal displays
(LCDs), touch screen displays, keyboards, keypads, switches, dials,
mice, track balls, voice recognizers, card readers, paper tape
readers, printers, video monitors, or other well-known input
devices. Also, the transceiver 1325 might be considered to be a
component of the I/O devices 1360 instead of or in addition to
being a component of the network connectivity devices 1320.
[0063] The following are incorporated herein by reference for all
purposes: 3rd Generation Partnership Project (3GPP) Technical
Specification (TS) 36.813 and 3GPP TS 36.814.
[0064] Thus, the illustrative embodiments provide for a user agent
capable of autonomous combining. The user agent can be implemented
as a processor configured to promote receiving a first signal from
an access node and a second signal from a relay node. The processor
may be further configured to combine the first and second
signals.
[0065] The illustrative embodiments further provide for a method
implemented in a user agent. A first signal is received from an
access node. A second signal is received from a relay node. The
first and second signals are combined.
[0066] The illustrative embodiments further provide for an access
node. The access node is configured to reserve ones of sets of
addresses for corresponding ones of a plurality of relay nodes.
Ones of the set of addresses comprise a corresponding first set of
bits and a corresponding second set of bits. A particular first set
of bits identifies a particular relay node. A particular second set
of bits identifies a particular UA within a donor cell of the
particular relay node. The access node is further configured to
transmit the ones of sets of addresses to the plurality of relay
nodes.
[0067] While several embodiments have been provided in the present
disclosure, it should be understood that the disclosed systems and
methods may be embodied in many other specific forms without
departing from the spirit or scope of the present disclosure. The
present examples are to be considered as illustrative and not
restrictive, and the intention is not to be limited to the details
given herein. For example, the various elements or components may
be combined or integrated in another system or certain features may
be omitted, or not implemented.
[0068] Also, techniques, systems, subsystems and methods described
and illustrated in the various embodiments as discrete or separate
may be combined or integrated with other systems, modules,
techniques, or methods without departing from the scope of the
present disclosure. Other items shown or discussed as coupled or
directly coupled or communicating with each other may be indirectly
coupled or communicating through some interface, device, or
intermediate component, whether electrically, mechanically, or
otherwise. Other examples of changes, substitutions, and
alterations are ascertainable by one skilled in the art and could
be made without departing from the spirit and scope disclosed
herein.
[0069] What is claimed is:
* * * * *