U.S. patent application number 12/889994 was filed with the patent office on 2011-06-30 for distributed simultaneous transmit and relay system.
Invention is credited to Alexander Maltsev, Amir Rubin, Vadim S. Sergeyev.
Application Number | 20110159801 12/889994 |
Document ID | / |
Family ID | 44187548 |
Filed Date | 2011-06-30 |
United States Patent
Application |
20110159801 |
Kind Code |
A1 |
Maltsev; Alexander ; et
al. |
June 30, 2011 |
DISTRIBUTED SIMULTANEOUS TRANSMIT AND RELAY SYSTEM
Abstract
Briefly, in accordance with one or more embodiments, a
distributed simultaneous transmit and receive system implements
relaying without incurring the additional overhead associated with
relaying and without requiring additional isolation techniques to
isolate the transmit and receive circuits of the relay stations.
During a first transmission resource, a base station transmits to a
first relay station while a second relay station transmits to one
or more mobile stations associated with the second relay station.
During a second transmission resource, the base station transmits
to the second relay station while the first relay station transmits
to one or more mobile stations associated with the first relay
station.
Inventors: |
Maltsev; Alexander; (US)
; Sergeyev; Vadim S.; (US) ; Rubin; Amir;
(US) |
Family ID: |
44187548 |
Appl. No.: |
12/889994 |
Filed: |
September 24, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61291787 |
Dec 31, 2009 |
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Current U.S.
Class: |
455/7 |
Current CPC
Class: |
H04W 52/10 20130101;
H04L 27/2626 20130101; H04L 1/0606 20130101; H04W 52/36 20130101;
H04B 7/0617 20130101; H04L 27/3444 20130101; H04L 27/2634 20130101;
H04W 52/146 20130101; H04L 25/08 20130101; H04W 72/082 20130101;
H04B 7/0413 20130101 |
Class at
Publication: |
455/7 |
International
Class: |
H04B 7/14 20060101
H04B007/14 |
Claims
1. A method, comprising: during a first time frame, transmitting to
a first relay station while a second relay station transmits to one
or more mobile stations associated with the second relay station;
and during a second time frame, transmitting to the second relay
station while the first relay station transmits to one or more
mobile stations associated with the first relay station.
2. A method as claimed in claim 1, wherein the first time frame
comprises a first subframe of a given frame, and the second time
frame comprises a second subframe of the given frame.
3. A method as claimed in claim 1, wherein at least one or more
mobile stations associated with the first relay station and one or
more of the mobile stations associated with the second relay
stations are the same mobile stations such that one or more mobile
stations are associated with both the first relay station and the
second relay station.
4. A method as claimed in claim 1, further comprising: during the
first time frame, transmitting to the first relay station and to a
presently associated mobile station while the second relay station
transmits to one or more mobile stations associated with the second
relay station; and during the second time frame, transmitting to
the second relay station and to a presently associated mobile
station while the first relay station transmits to one or more
mobile stations associated with the first relay station.
5. A method, comprising: during a first time frame, receiving data
from a first relay station while a second relay station receives
data from one or more mobile stations associated with the second
relay station; and during a second time frame, receiving data from
the second relay station while the first relay station receives
data from one or more mobile stations associated with the first
relay station.
6. A method as claimed in claim 5, wherein the first time frame
comprises a first subframe of a given frame, and the second time
frame comprises a second subframe of the given frame.
7. A method as claimed in claim 5, wherein at least one or more
mobile stations associated with the first relay station and one or
more of the mobile stations associated with the second relay
stations are the same mobile stations such that one or more mobile
stations are associated with both the first relay station and the
second relay station.
8. A method as claimed in claim 5, further comprising: during the
first time frame, receiving data from the first relay station and
from a presently associated mobile station while the second relay
station receives data from one or more mobile stations associated
with the second relay station; and during the second time frame,
receiving data from the second relay station and from a presently
associated mobile station while the first relay station receives
data from one or more mobile stations associated with the first
relay station.
9. A method, comprising: during a first time frame, transmitting to
a first group of relay stations while a second group of relay
stations transmits to one or more mobile stations associated with
the second group of relay stations; and during a second time frame,
transmitting to the second group of relay stations while the first
group of relay stations transmits to one or more mobile stations
associated with the first group of relay stations.
10. A method as claimed in claim 9, wherein said transmitting to
the first group of relay stations or to the second group of relay
stations, or combinations thereof, comprises using beamforming or
multiple-input and multiple output, or combinations thereof, to
provide simultaneous transmission of different data to different
respective relay stations in the first group of relay stations or
the second group of relay stations.
11. A method as claimed in claim 9, wherein the first group of
relay stations and the second group of relay stations changes
between one time frame and another time frame such that membership
of the first group of relay stations or membership of the second
group of relay stations, or combinations thereof, changes between
time frames.
12. A method, comprising: during a first time frame, receiving data
from a first group of relay stations while a second group of relay
stations receives data from one or more mobile stations associated
with the second group of relay stations; and during a second time
frame, receiving data from the second group of relay stations while
the first group of relay stations receives data from one or more
mobile stations associated with the first group of relay
stations.
13. A method as claimed in claim 12, wherein said receiving data
from the first group of relay stations or from the second group of
relay stations, or combinations thereof, comprises using
beamforming to provide simultaneous reception of different data
from different respective relay stations in the first group of
relay stations or the second group of relay stations.
14. A method as claimed in claim 12, wherein said receiving data
from the first group of relay stations or said receiving data from
the second group of relay stations, or combinations thereof,
comprises using multiple-input and multiple output to receive data
from the first group of relay stations or to the second group of
relay stations.
15. A method as claimed in claim 12, wherein the first group of
relay stations and the second group of relay stations changes
between one time frame and another time frame such that membership
of the first group of relay stations or membership the second group
of relay stations, or combinations thereof, changes between time
frames.
16. A method as claimed in claim 12, wherein at least one or more
mobile stations associated with the first group of relay stations
and one or more of the mobile stations associated with the second
group of relay stations are the same mobile stations such that one
or more mobile stations are associated with both the first group of
relay stations and the second group of relay stations.
17. An apparatus, comprising a processor and a memory coupled to
the processor; and a radio-frequency transceiver coupled to the
processor, wherein processor is configured via the memory to:
during a first time frame, transmit to a first relay station while
a second relay station transmits to one or more mobile stations
associated with the second relay station; and during a second time
frame, transmit to the second relay station while the first relay
station transmits to one or more mobile stations associated with
the first relay station.
18. An apparatus as claimed in claim 17, wherein the processor is
further configured to cause the radio-frequency transceiver to:
during a third time frame, transmit to a third relay station while
the first relay station transmits to the one or more mobile
stations associated with the first relay station and the second
relay station transmits to the one or more mobile stations
associated with the second relay station.
19. An apparatus, comprising a processor and a memory coupled to
the processor; and a radio-frequency transceiver coupled to the
processor, wherein processor is configured via the memory to:
during a first time frame, receive data from the first relay
station while the second relay station receives data from one or
more mobile stations associated with the second relay station; and
during a second time frame, receive data from the second relay
station while the first relay station receives data from one or
more mobile stations associated with the first relay station.
20. A method, comprising: during a first time frame, receiving data
transmitted from a base station while one or more other relay
stations transmit to one or more mobile stations associated with
the one or more other relay stations; and during a second time
frame, transmitting the data received from the base station to one
or more presently associated mobile stations while the one or more
other relay stations receive data transmitted from the base
station.
21. A method, comprising: during a first time frame, receiving data
from the one or more presently associated mobile stations while the
one or more other relay stations transmit to the base station; and
during a second time frame, transmitting the data received from the
one or more presently associated mobile stations to the base
station while the one or more other relay stations receive data
from the one or more mobile stations associated with the one or
more other relay stations.
22. A method, comprising: during a first time frame, receiving data
transmitted from a first relay station while a second relay station
receives data transmitted from a base station; and during a second
time frame, not receiving any data transmitted from the first relay
station while the first relay station receives data transmitted
from the base station and the second relay station transmits data
to one or more mobile station associated with the second relay
station.
23. A method, comprising: during a first time frame, transmitting
data to the first relay station while the second relay station
transmits data to the base station; and during a second time frame,
not transmitting any data to the first relay station while the
first relay station transmits data to the base station and the
second relay station receives data from the one or more mobile
station associated with the second relay station.
24. A method, comprising: during a first time frame, transmitting
data to the first relay station while the second relay station
transmits data to the base station; and during a second time frame,
transmitting data to the second relay station while the first relay
station transmits data to the base station.
25. A method, comprising: during a first time frame, receiving data
transmitted from a first relay station while a second relay station
receives data transmitted from a base station; and during a second
time frame, receiving data transmitted from the second relay
station while the first relay station receives data transmitted
from the base station.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims the benefit of U.S.
Provisional Application No. 61/291,787 (Attorney Docket No.
P33337Z) filed Dec. 31, 2009. Said Application No. 61/291,787 is
hereby incorporated herein in its entirety.
BACKGROUND
[0002] Relaying of a data burst in wireless cellular networks with
conventional decode and forward relay station involves additional
overhead in the form of base station (BS) to relay station (RS)
data transmissions. Using a relay station consumes additional time
and/or frequency resources that otherwise could be used to deliver
data to the mobile station (MS). To overcome this problem, one
approach is to utilize a specially designed relay station having
simultaneous transmit and receive (STR) operation capability. Such
STR relay stations are capable of receiving data from the base
station while simultaneously transmitting the data to the mobile
stations, and vice versa, in the same time-frequency resource.
Therefore, an STR relay station does not incur additional base
station to relay station overhead. However, STR relay stations may
have a substantial drawback in that they require a very high degree
of mutual insulation of the antennas between the Relay link (base
station to relay station) and the Access link (relay station to
mobile station) to avoid strong interference from the transmission
signal of one link onto the receive circuits of the other link.
Thus, STR relay stations typically require additional interference
cancellers at both links, which complicates the relay station
design and leads to higher equipment cost.
DESCRIPTION OF THE DRAWING FIGURES
[0003] Claimed subject matter is particularly pointed out and
distinctly claimed in the concluding portion of the specification.
However, such subject matter may be understood by reference to the
following detailed description when read with the accompanying
drawings in which:
[0004] FIGS. 1A, 1B, 1C, and 1D are block diagrams of a distributed
simultaneous transmit and receive relay system in accordance with
one or more embodiments;
[0005] FIG. 2 is a diagram of distributed simultaneous transmit and
receive operations wherein two relays per sector are deployed in
accordance with one or more embodiments;
[0006] FIG. 3 is a diagram of a simultaneous transmit and receive
operation in the downlink wherein an arbitrary number of relays per
sector is deployed in accordance with one or more embodiments;
[0007] FIG. 4 is a diagram of a simultaneous transmit and receive
operation in the uplink wherein an arbitrary number of relays per
sector is deployed in accordance with one or more embodiments;
[0008] FIG. 5 is a block diagram of distributed simultaneous
transmit and receive system showing downlink transmissions
corresponding to different time instances in accordance with one or
more embodiments;
[0009] FIG. 6 is a block diagram of distributed simultaneous
transmit and receive system showing uplink transmissions
corresponding to different time instances in accordance with one or
more embodiments;
[0010] FIG. 7 is a block diagram of distributed simultaneous
transmit and receive operations in the downlink and the uplink
wherein four relays per sector are deployed using multiuser
multiple-input and multiple output (MU-MIMO) on the relay links in
accordance with one or more embodiments;
[0011] FIG. 8 is a block diagram of a distributed simultaneous
transmit and receive system using multiuser multiple-input and
multiple output (MU-MIMO) on the relay links in accordance with one
or more embodiments;
[0012] FIG. 9 is a diagram showing example embodiments simultaneous
transmit and receive operation in downlink frames in accordance
with one or more embodiments;
[0013] FIG. 10 is a diagram showing example embodiments
simultaneous transmit and receive operation in uplink frames in
accordance with one or more embodiments; and
[0014] FIG. 11 is a block diagram of an information handling system
capable of implementing distributed simultaneous transmit and
receive operations in accordance with one or more embodiments.
[0015] It will be appreciated that for simplicity and/or clarity of
illustration, elements illustrated in the figures have not
necessarily been drawn to scale. For example, the dimensions of
some of the elements may be exaggerated relative to other elements
for clarity. Further, if considered appropriate, reference numerals
have been repeated among the figures to indicate corresponding
and/or analogous elements.
DETAILED DESCRIPTION
[0016] In the following detailed description, numerous specific
details are set forth to provide a thorough understanding of
claimed subject matter. However, it will be understood by those
skilled in the art that claimed subject matter may be practiced
without these specific details. In other instances, well-known
methods, procedures, components and/or circuits have not been
described in detail.
[0017] In the following description and/or claims, the terms
coupled and/or connected, along with their derivatives, may be
used. In particular embodiments, connected may be used to indicate
that two or more elements are in direct physical and/or electrical
contact with each other. Coupled may mean that two or more elements
are in direct physical and/or electrical contact. However, coupled
may also mean that two or more elements may not be in direct
contact with each other, but yet may still cooperate and/or
interact with each other. For example, "coupled" may mean that two
or more elements do not contact each other but are indirectly
joined together via another element or intermediate elements.
Finally, the terms "on," "overlying," and "over" may be used in the
following description and claims. "On," "overlying," and "over" may
be used to indicate that two or more elements are in direct
physical contact with each other. However, "over" may also mean
that two or more elements are not in direct contact with each
other. For example, "over" may mean that one element is above
another element but not contact each other and may have another
element or elements in between the two elements. Furthermore, the
term "and/or" may mean "and", it may mean "or", it may mean
"exclusive- or", it may mean "one", it may mean "some, but not
all", it may mean "neither", and/or it may mean "both", although
the scope of claimed subject matter is not limited in this respect.
In the following description and/or claims, the terms "comprise"
and "include," along with their derivatives, may be used and are
intended as synonyms for each other.
[0018] Referring now to FIGS. 1A, 1B, 1C, and 1D, block diagrams of
a distributed simultaneous transmit and receive relay system in
accordance with one or more embodiments will be discussed. As
shown, a distributed simultaneous transmit and receive (D-STR)
system 100 may comprise a base station (BS) 110 to communicate with
one or more mobile stations such as a first mobile station (MS1)
116 and a second mobile station (MS2) 118. In one or more
embodiments, distributed simultaneous transmit and receive system
100 may be operated in compliance with an Institute of Electrical
and Electronics Engineers (IEEE) standard such as the IEEE 802.16m
Task Group m (TGm) standard to implement a Worldwide
Interoperability of Microwave Access (WiMAX) protocol or the like,
or alternatively in compliance with a Long Term Evolution (LTE)
standard such as the Third Generation Partnership Project (3GPP)
Long Term Evolution-Advanced (LTE-Advanced) standard or the like,
or any subsequent versions of such standards, and the scope of the
claimed subject matter is not limited in this respect. In one or
more embodiments, two or more relay stations such as a first relay
station (RS1) 112 and a second relay station (RS2) 114 may be
deployed between base station 110 and the mobile stations 116 and
118 to retransmit the signals between the broadcasting elements in
order to enhance the signal strength and extend the operable range
of communication between the base station and the mobile stations.
In general, in accordance with one or more embodiments, two or more
relay stations are utilized in order to implement simultaneous
transmitting and receiving of the signals between the base station
and the mobile stations. For example, as shown in FIG. 1A, in a
first time slot for downlink transmission, base station 120
transmits to relay station (RS1) 112 via transmission 120, and
relay station (RS2) 114 transmits to relay mobile station (MS2) 118
via transmission 122. As shown in FIG. 1B, in a next time slot for
downlink transmission, base station 110 transmits to the relay
station (RS2) 114 via transmission 124, and relay station (RS1) 112
transmits to mobile station (MS1) 116 via transmission 126.
Likewise, as shown in FIG. 1C, in a first time slot for uplink
transmission, relay station (RS1) 112 transmits to base station 110
via transmission 128, and mobile station (MS2) 118 transmits to
relay stations (RS2) 114 via transmission 130. As shown in FIG. 1D,
in a next time slot for uplink transmission, relay station (RS2)
114 transmits to base station 110 via transmission 132, and mobile
station (MS1) 116 transmits to relay station (RS1) 112 via
transmission 134. In general, in the distributed simultaneous
transmit and receive (D-STR) system 100 shown in FIG. 1A-1D, at
least two relay stations are deployed to implement simultaneous
transmitting and receiving of signals wherein a first relay station
is receiving while a second relay station is transmitting, and then
alternatively the first relay stations is transmitting while the
second relay station is receiving. In a more generalized embodiment
of D-STR system 100, one or more relay stations are receiving while
one or more other relay stations are transmitting, and then
alternatively one more relay stations are transmitting while one or
more other relay stations are receiving. An example D-STR system
100 wherein two relays per a given sector are deployed is shown in
and described with respect to FIG. 2, below, and more generalized
embodiments are shown in and described subsequently, below.
[0019] Referring now to FIG. 2, a diagram of distributed
simultaneous transmit and receive operations wherein two relays per
sector are deployed in accordance with one or more embodiments will
be discussed. The basic principles of operation of a two relay
embodiment of distributed simultaneous transmit and receive (D-STR)
operation are shown in FIG. 2 with respect to the D-STR system 100
of FIGS. 1A-1D. As shown in FIG. 2, a simple example of data
transmission protocol in accordance with the proposed scheme for
deployment with two relays per sector is illustrated. However, it
should be known that although FIG. 2 merely describes an example of
two relays per sector, the D-STR concept discussed herein may be
extrapolated to any number of relays per sector, and the scope of
the claimed subject matter is not limited in this respect. For the
downlink (DL) 200, in the first time slot (TIME SLOT 1) the base
station BS 110 sends the data to the first relay station RS1 112
via transmission 120, and in the same time slot the second relay
station RS2 114 sends the data, previously obtained from the base
station in an earlier time slot (not shown), to mobile station MS2
associated with relay station RS2 114 via transmission 122. In the
second time slot (TIME SLOT 2) for the downlink 200, base station
BS 110 sends the data to the second relay station RS2 114 via
transmission 124, and the first relay station RS1 112 sends the
data, received in the first time slot from base station BS 120, to
mobile station MS1 116 associated with the first relay station RS1
112 via transmission 126. For the Uplink (UL) 210, the operation is
similar to that of the downlink (DL) 200 via transmissions 128,
130, 132, and 134. In such an arrangement, the two relay stations,
RS1 112 and RS2 114, together may be viewed as distributed relay
system having the simultaneous transmit and receive (STR)
capability of distributed simultaneous transmit and receive (D-STR)
system 100. In this D-STR system 100, the insulation between the
access and the relay links may be achieved with better performance
versus typical STR relays due to substantial distance between the
simultaneously and alternating operating transmitters and receivers
of the two relays RS1 112 and RS 114, however, the scope of the
claimed subject matter is not limited in this respect. Although
FIGS. 1A-1D and FIG. 2 illustrate the D-STR system 100 for the case
of two relays, a D-STR system having an arbitrary number of relays,
for example 4 relays, is shown in and described with respect to
FIG. 3 through FIG. 6, below.
[0020] Referring now to FIG. 3, a diagram of a simultaneous
transmit and receive operation in the downlink wherein an arbitrary
number of relays per sector is deployed in accordance with one or
more embodiments will be discussed. As shown in FIG. 3, for a
deployment of more than two relays per sector generalized
transmission protocol may be extrapolated to implement distributed
simultaneous transmit and receive (D-STR) with multiple relays,
with four relays and four mobile stations in the example shown. In
this protocol, the transmission time may be divided into the number
of time slots equal to the number of the relay stations. Each of
the relay stations may receive data from base station BS 110 in one
slot, for example in the time slot corresponding to the relay
station's number. When not receiving data from the base station
110, a given relay stations sends the data received from the base
station 110 to its served mobile station or stations in all other
time slots. Since the spectral efficiency of the relay links is
typically much higher than the access links, a good load balance
for relay stations may be achieved in such an arrangement.
Additionally, to enhance overall system performance, the base
station BS 110 may apply beamforming when transmitting to a given
relay station in order to avoid interference on the transmissions
between the other relay stations and their respective relay
stations. For example, in the time slot 1 (310), the base station
110 may steer its beam onto relay station RS1 to deliver data to
RS1 at a high speed and at the same time reduce the interference
onto the mobile stations served by all other relay stations RS2,
RS3, and RS4. In other time slots, such as time slot 2 (312), time
slot 3 (314), and time slot 4 (316), the base station 110 may steer
its beam onto the other relay stations, respectively. Thus, relay
station RS1 may receive data from the base station 110 in time slot
1 (310) and may transmit to its mobile station MS1 in time slots
2-4 (312, 314, and 316). Relay station RS2 may receive data from
the base station 110 in time slot 2 (312) and may transmit to its
mobile station MS2 in time slots 1 and 3-4 (310, 314, and 316).
Relay station RS3 may receive data from the base station 110 in
time slot 3 (314) and may transmit to mobile station MS3 in time
slots 1-2 and 4 (310, 312, and 316). Relay station RS4 may receive
data from the base station 110 in time slot 4 (316) and may
transmit to mobile station MS4 in time slots 1-3 (310, 312, and
316). Although in the example shown in FIG. 3 each relay station
serves one mobile station, in other embodiments a relay station may
serve two or more mobile stations, and the scope of the claimed
subject matter is not limited in this respect.
[0021] Referring now to FIG. 4, a diagram of a simultaneous
transmit and receive operation in the uplink wherein an arbitrary
number of relays per sector is deployed in accordance with one or
more embodiments will be discussed. While FIG. 3 illustrates the
downlink, FIG. 4 illustrates how D-STR system 100 operates in the
uplink and symmetrically with respect to the downlink. As shown in
FIG. 4, each relay station may collect data from one or more mobile
stations associated with the corresponding relay station during all
time slots except for one time slot which, for example, is the time
slip corresponding to the number of the relay station. During the
time slot corresponding to the respective relay station number, the
relay station sends the data collected from its mobile stations to
the base station BS 110. For example, relay station RS1 receives
data from base station 110 in time slot 1 (410), and receives data
from mobile station MS1 in time slots 2-4 (412, 414, and 416).
Relay station RS2 receives data from base station 110 in time slot
2 (412), and receives data from mobile station MS2 in time slots 1
and 3-4 (410, 414, and 416). Relay station RS3 receives data from
base station 110 in time slot 3 (414), and receives data from
mobile station MS3 in time slots 1-2 and 4 (410, 412, and 416).
Relay station RS 4 receives data from base station 110 in time slot
4 (416), and receives data from mobile station MS4 in time slot 1-3
(410, 412, and 414). Although in the example shown in FIG. 5 each
relay station serves one mobile station, in other embodiments a
relay station may serve two or more mobile stations, and the scope
of the claimed subject matter is not limited in this respect.
[0022] Referring now to FIG. 5 and FIG. 6, a block diagram of
distributed simultaneous transmit and receive system showing
downlink transmissions (FIG. 5) and uplink transmissions (FIG. 6)
corresponding to different time instances in accordance with one or
more embodiments will be discussed. FIG. 5 and FIG. 6 show the
transmission diagrams for the operation of the distributed
simultaneous transmit and receive (D-STR) system in an example of
deployment with four relays per sector for downlink as shown in
FIG. 3, and for the uplink as shown in FIG. 4, respectively.
Considering the downlink as shown in FIG. 5, in the first time slot
(310), the base station 110 sends the data to relay station RS1,
and all other relay stations send data to their respective
associated base stations. In the second time slot (312) the base
station 110 sends the data to relay station RS2, and all other
relay stations send data to their respective associated with mobile
stations. The D-STR system operates similarly for the third time
slot (314) and the fourth timeslot (316). In the uplink as shown in
FIG. 6, the operation is symmetrical with respect to the downlink
for time slots 410, 412, 414, and 416. Although an example of a
D-STR system 100 is shown in FIG. 3, FIG. 4, FIG. 5, and FIG. 6
illustrating a four relay system, it should be noted that D-STR
system 100 ma be generalized to any number of relays, and the scope
of the claimed subject matter is not limited in this respect.
[0023] Referring now to FIG. 7 and FIG. 8, a block diagrams of
distributed simultaneous transmit and receive operations in the
downlink and the uplink wherein four relays per sector are deployed
using multiuser multiple-input and multiple output (MU-MIMO) on the
relay links in accordance with one or more embodiments will be
discussed. Extrapolating the distributed simultaneous transmit and
receive (D-STR) system 100 to multiple antenna systems, the
aggregate spectral efficiency of the D-STR system 100 with relays
may be further improved via utilization of a multiple-input and
multiple-output (MIMO) capable base station 110. As shown in FIG.
7, to organize distributed simultaneous transmit and receive (STR)
and/or quasi-STR operation of the relay stations in a MIMO
deployment, the relay stations may be organized into several
groups, with at least one group having two or more relay stations.
In such an arrangement, the D-STR system 100 described herein,
above, may be applied between each group of relay stations. The
aggregate spectral efficiency in a given cell may be enhanced by
delivering the data to several relays members of a given group in
parallel, that is simultaneously, by using different spatial
multiplexing (SM) schemes. For example, for the deployment with
four relay stations per sector with a MIMO capable base station BS
110, the relay stations may be split into two groups, wherein the
first group comprises relay stations RS1 and RS2, and the second
group comprises relay station RS3 and RS4. The data transmission
may be organized as shown in FIG. 7 and in FIG. 8. For example, for
the downlink 700, in time slot 1 base station 110 transmits to
relay stations RS1 and RS2 via transmission 720, and relay stations
RS3 and RS4 transmit to respective mobile stations MS3 and MS4 via
transmission 720. In time slot 2 base station 110 transmits to
relay stations RS3 and RS4 via transmission 724, and relay stations
RS1 and RS2 transmit to respective mobile stations MS1 and MS2 via
transmission 726. Likewise, for the uplink 710, in time slot 1 base
station 110 receives data from relay stations RS1 and RS2 via
transmission 728, and relay stations RS3 and RS4 receive data from
respective mobile stations MS3 and MS4 via transmission 730. In
time slot 2 base station 110 receives data from relay stations RS3
and RS4 via transmission 732, and relay stations RS1 and RS2
receive data from respective mobile stations MS1 and MS2 via
transmission 734. It should be noted that base station 110 may
implement MIMO communication between multiple relay stations in
respective groups, the relay stations themselves may also implement
MIMO communication between multiple mobile stations served by the
respective relay stations, and the scope of the claimed subject
matter is not limited in this respect. Furthermore, although FIG. 7
and FIG. 8 illustrate an example of two groups of two relay
stations per group of relay stations, it should be noted that any
arbitrary number of groups may be utilized, and a given group of
relay stations may have any arbitrary number of relay stations in
the group, and the scope of the claimed subject matter is not
limited in these respects.
[0024] Referring now to FIG. 9 and FIG. 10, a diagrams showing
example embodiments of simultaneous transmit and receive operation
in downlink frames (FIG. 9) and uplink frames (FIG. 10) in
accordance with one or more embodiments will be discussed. As an
example, FIG. 9 and FIG. 10 show the implementation of the
distributed simultaneous transmit and receive (D-STR) system in a
frame structure in accordance with an Institute of Electrical and
Electronics Engineers (IEEE) standard such as the IEEE 802.16m
frame structure. As shown in FIG. 9 and FIG. 10, the frame
structure of the IEEE 802.16m standard is based on subframes
comprising several subframes in the downlink (DL) part of the frame
(FIG. 9) and several subframes in the uplink (UL) part of the frame
(FIG. 10). Data transmissions in the IEEE 802.16m standard are
aligned to subframe time boundaries. In downlink and uplink parts
of the frame, the last several subframes may be utilized to create
a D-STR Relay Zone, wherein base station BS 100 communicates with
the relay stations and wherein the D-STR operation may be
implemented. The rest of the subframes comprise the DL and UL
Access Zones where communications between the base station 110 and
the mobile stations and between the relay stations and mobile
stations are implemented.
[0025] In the D-STR Relay Zone 910, several embodiments of
implementing D-STR technique may be implemented. In a first
embodiment, under a frame-wise approach 912, in the downlink D-STR
Relay Zone 910 (FIG. 9), in a first frame 914 relay station RS1
receives data from the base station 100, and relay station RS2
transmits data to its mobile stations. In the D-STR Relay Zone 910
of another frame 916, the relay stations do the opposite wherein
relay station RS1 distributes data to its mobile stations, and
relay station RS2 receives data from the base station 110. In the
Uplink as shown in FIG. 10, the frame-wise approach 912 operation
is similar to the downlink frame-wise approach operation with
transmissions occurring in the reverse direction. Implementing such
a frame-wise approach 912 in the frame structure defined in the
IEEE 802.16m standard involves allowing a given relay station to
serve its mobile stations in the D-STR Relay Zone 910 with RS-MS
transmission in the downlink and MS-RS transmission in the uplink.
In such an arrangement, configuration messages and/or information
elements are modified accordingly to accommodate D-STR
operation.
[0026] In another embodiment, D-STR is implemented via a
subframe-wise approach 918. Under a subframe-wise approach the
relay stations alternate their roles within the same frame from one
subframe to another subframe. For example, with reference to FIG.
9, in the downlink in the first subframe 920 of D-STR Relay Zone
910, relay station RS1 receives data from base station 110, and
relay station RS2 transmits data to its mobile stations. In the
second subframe 922 of D-STR Relay Zone 910, relay station RS1
distributes the data to its mobile stations, and relay station RS2
receives data from the base station 110. Operation of the
subframe-wise approach 918 in the uplink is similar as shown in
FIG. 10 with transmissions occurring in the reverse direction.
[0027] The subframe-wise approach for three D-STR relays is shown
at 924. The three or more relay approach may involve three or more
corresponding subframes of the frame. Since the entire D-STR cycle
completes within the same frame, the subframe-wise approach has
less latency of data transmissions to the mobile stations
associated with corresponding relay stations. However, since this
approach requires more frequent transition of the relay between the
transmit (TX) and receive (RX) states, implementing a subframe-wise
approach may involve introduction of additional receive-transmit
gaps on the base station to relay station links. In case of
zero-length gaps, the subframe-wise approach may be implemented in
the IEEE 802.16m or Third Generation Partnership Project (3GPP)
Long Term Evolution-Advanced (LTE-Advanced) standards, however the
scope of the claimed subject matter is not limited in these
respects.
[0028] Although the examples shown and described herein illustrate
various approaches to single-hop relaying to implement a
distributed simultaneous transmit and receive (D-STR) system 100,
in one or more embodiments the D-STR system 100 may be extrapolated
to provide multi-hop relaying operation with an arbitrary number of
hops and which may be implemented in compliance with future
revisions or versions of one or more IEEE 802.16 standards or Third
Generation Partnership Project (3GPP) Long Term Evolution-Advanced
(LTE-Advanced) standard or the like, and the scope of the claimed
subject matter is not limited in this respect. An example of an
information handling system capable of implementing distributed
simultaneous transmit and receive (D-STR) operation in a D-STR
system 100 is shown in and described with respect to FIG. 11,
below.
[0029] Referring now to FIG. 11, a block diagram of an information
handling system capable of implementing distributed simultaneous
transmit and receive operations in accordance with one or more
embodiments will be discussed. Information handling system 1100 of
FIG. 11 may tangibly embody one or more of any of the network
elements of distributed simultaneous transmit and receive (D-STR)
system 100 as shown in and described with respect to FIGS. 1A-1D
and the other various alternative embodiments discussed herein. For
example, information handling system 1100 may represent the
hardware of base station 110, relay stations 112 and 114, or mobile
stations 116 and 118, with greater or fewer components depending on
the hardware specifications of the particular device or network
element. Although information handling system 1100 represents one
example of several types of computing platforms, information
handling system 1100 may include more or fewer elements and/or
different arrangements of elements than shown in FIG. 11, and the
scope of the claimed subject matter is not limited in these
respects.
[0030] Information handling system 1100 may comprise one or more
processors such as processor 1110 and/or processor 1112, which may
comprise one or more processing cores. One or more of processor
1110 and/or processor 1112 may couple to one or more memories 1116
and/or 1118 via memory bridge 1114, which may be disposed external
to processors 1110 and/or 1112, or alternatively at least partially
disposed within one or more of processors 1110 and/or 1112. Memory
1116 and/or memory 1118 may comprise various types of semiconductor
based memory, for example volatile type memory and/or non-volatile
type memory. Memory bridge 1114 may couple to a graphics system
1120 to drive a display device (not shown) coupled to information
handling system 1100.
[0031] Information handling system 1100 may further comprise
input/output (I/O) bridge 1122 to couple to various types of I/O
systems. I/O system 1124 may comprise, for example, a universal
serial bus (USB) type system, an IEEE 1394 type system, or the
like, to couple one or more peripheral devices to information
handling system 1100. Bus system 1126 may comprise one or more bus
systems such as a peripheral component interconnect (PCI) express
type bus or the like, to connect one or more peripheral devices to
information handling system 1100. A hard disk drive (HDD)
controller system 1128 may couple one or more hard disk drives or
the like to information handling system, for example Serial ATA
type drives or the like, or alternatively a semiconductor based
drive comprising flash memory, phase change, and/or chalcogenide
type memory or the like. Switch 1130 may be utilized to couple one
or more switched devices to I/O bridge 1122, for example Gigabit
Ethernet type devices or the like. Furthermore, as shown in FIG.
11, information handling system 1100 may include a radio-frequency
(RF) block 1132 comprising RF circuits and devices for wireless
communication with other wireless communication devices and/or via
wireless networks such as D-STR system 100 of FIG. 1 or the various
alternative embodiments discussed herein, for example where
information handling system 1100 embodies base station 110, relay
stations 112 and 114 and, or mobile stations 116 and 118, although
the scope of the claimed subject matter is not limited in this
respect.
[0032] Although the claimed subject matter has been described with
a certain degree of particularity, it should be recognized that
elements thereof may be altered by persons skilled in the art
without departing from the spirit and/or scope of claimed subject
matter. It is believed that the subject matter pertaining to a
distributed simultaneous transmit and receive relay system and/or
many of its attendant utilities will be understood by the forgoing
description, and it will be apparent that various changes may be
made in the form, construction and/or arrangement of the components
thereof without departing from the scope and/or spirit of the
claimed subject matter or without sacrificing all of its material
advantages, the form herein before described being merely an
explanatory embodiment thereof, and/or further without providing
substantial change thereto. It is the intention of the claims to
encompass and/or include such changes.
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