U.S. patent application number 12/619170 was filed with the patent office on 2011-05-05 for method for forwarding in peer-to-peer wireless communications.
This patent application is currently assigned to QUALCOMM Incorporated. Invention is credited to Santosh P. Abraham, Avinash Jain, Hemanth Sampath, Mohammad Hossein Taghavi Nasrabadi.
Application Number | 20110103240 12/619170 |
Document ID | / |
Family ID | 43925339 |
Filed Date | 2011-05-05 |
United States Patent
Application |
20110103240 |
Kind Code |
A1 |
Taghavi Nasrabadi; Mohammad Hossein
; et al. |
May 5, 2011 |
METHOD FOR FORWARDING IN PEER-TO-PEER WIRELESS COMMUNICATIONS
Abstract
Certain aspects of the present disclosure relate to a method for
forwarding of data in peer-to-peer transactions by a
high-capability wireless device, such as an access point.
Inventors: |
Taghavi Nasrabadi; Mohammad
Hossein; (San Diego, CA) ; Sampath; Hemanth;
(San Diego, CA) ; Abraham; Santosh P.; (San Diego,
CA) ; Jain; Avinash; (San Diego, CA) |
Assignee: |
QUALCOMM Incorporated
San Diego
CA
|
Family ID: |
43925339 |
Appl. No.: |
12/619170 |
Filed: |
November 16, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61255971 |
Oct 29, 2009 |
|
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Current U.S.
Class: |
370/252 ;
370/328; 370/392 |
Current CPC
Class: |
H04W 84/047 20130101;
H04W 4/00 20130101; H04W 8/005 20130101; H04W 72/085 20130101; H04W
24/10 20130101 |
Class at
Publication: |
370/252 ;
370/328; 370/392 |
International
Class: |
H04W 40/00 20090101
H04W040/00; H04L 12/26 20060101 H04L012/26 |
Claims
1. A method for wireless communications by a source apparatus,
comprising: exchanging messages with an apparatus capable of
forwarding data to a destination apparatus; determining, based on
the exchange of messages, whether to send data to the destination
apparatus via the forwarding apparatus or to send the data directly
to the destination apparatus; and transmitting data to the
destination apparatus based on the determination.
2. The method of claim 1, wherein: the exchange comprises
exchanging one or more messages indicating at least one channel
condition; and the determination comprises determining, based on
the at least one channel condition, whether it is preferable to
send the data to the destination apparatus via the forwarding
apparatus or to send the data directly to the destination
apparatus.
3. The method of claim 2, wherein the at least one channel
condition comprises at least one of: channel condition of a link
between the source apparatus and the forwarding apparatus or
channel condition of a link between the forwarding apparatus and
the destination apparatus.
4. The method of claim 1, further comprising: deciding, prior to
the transmission based on the determination, to transmit the data
to the destination apparatus via the forwarding apparatus; and
transmitting an announcement message about the decision to the
forwarding apparatus.
5. The method of claim 4, wherein the announcement message is
embedded in the data.
6. The method of claim 1, wherein the transmission comprises:
transmitting the data to the forwarding apparatus, the data
comprising an address of the destination apparatus, said address
indicates that the data should be forwarded to the destination
apparatus.
7. The method of claim 1, wherein: the exchange comprises
exchanging one or more messages indicating directional capability
of the forwarding apparatus and directional capability of the
source apparatus; and the determination comprises determining,
based on the directional capability of the forwarding apparatus and
the directional capability of the source apparatus, whether it is
preferable to send the data to the destination apparatus via the
forwarding apparatus or to send the data directly to the
destination apparatus.
8. The method of claim 1, wherein: the exchange comprises
exchanging one or more messages indicating a transmission power of
the forwarding apparatus and a transmission power of the source
apparatus; and the determination comprises determining, based on
the transmission power of the forwarding apparatus and the
transmission power of the source apparatus, whether it is
preferable to send the data to the destination apparatus via the
forwarding apparatus or to send the data directly to the
destination apparatus.
9. The method of claim 1, wherein: the exchange comprises
exchanging one or more messages indicating one or more beamforming
gains of the forwarding apparatus and one or more beamforming gains
of the source apparatus; and the determination comprises
determining, based on the one or more beamforming gains of the
forwarding apparatus and the one or more beamforming gains of the
source apparatus, whether it is preferable to send the data to the
destination apparatus via the forwarding apparatus or to send the
data directly to the destination apparatus.
10. The method of claim 1, wherein the exchange comprises:
transmitting a request message to the forwarding apparatus; and
receiving, from the forwarding apparatus, a response message
indicating whether the data should be sent directly to the
destination apparatus or forwarded to the destination apparatus via
the forwarding apparatus.
11. The method of claim 1, wherein a portion of the data is
transmitted to the forwarding apparatus to be forwarded to the
destination apparatus before transmitting another portion of the
data to the forwarding apparatus, and the method further
comprising: receiving an acknowledgement from the forwarding
apparatus that the portion of the data is successfully received at
the forwarding apparatus, wherein the portion of the data is not
yet forwarded from the forwarding apparatus to the destination
apparatus.
12. The method of claim 11, further comprising: receiving, from the
forwarding apparatus, an acknowledgement that the portion of the
data was successfully received at the destination apparatus,
wherein the destination apparatus sent the acknowledgment to the
forwarding apparatus.
13. An apparatus for wireless communications, comprising: a
transceiver configured to exchange messages with an apparatus
capable of forwarding data to a destination apparatus; and a
processor configured to determine, based on the exchange of
messages, whether to send data to the destination apparatus via the
forwarding apparatus or to send the data directly to the
destination apparatus, wherein the transceiver is also configured
to transmit data to the destination apparatus based on the
determination.
14. The apparatus of claim 13, wherein: the transceiver is also
configured to exchange one or more messages indicating at least one
channel condition; and the processor is also configured to
determine, based on the at least one channel condition, whether it
is preferable to send the data to the destination apparatus via the
forwarding apparatus or to send the data directly to the
destination apparatus.
15. The apparatus of claim 14, wherein the at least one channel
condition comprises at least one of: channel condition of a link
between the apparatus and the forwarding apparatus or channel
condition of a link between the forwarding apparatus and the
destination apparatus.
16. The apparatus of claim 13, wherein: the processor is also
configured to decide, prior to the transmission based on the
determination, to transmit the data to the destination apparatus
via the forwarding apparatus, and wherein the transceiver is also
configured to transmit an announcement message about the decision
to the forwarding apparatus.
17. The apparatus of claim 16, wherein the announcement message is
embedded in the data.
18. The apparatus of claim 13, wherein: the transceiver is also
configured to transmit the data to the forwarding apparatus, the
data comprising an address of the destination apparatus, said
address indicates that the data should be forwarded to the
destination apparatus.
19. The apparatus of claim 13, wherein: the transceiver is also
configured to exchange one or more messages indicating directional
capability of the forwarding apparatus and directional capability
of the apparatus; and the processor is also configured to
determine, based on the directional capability of the forwarding
apparatus and the directional capability of the apparatus, whether
it is preferable to send the data to the destination apparatus via
the forwarding apparatus or to send the data directly to the
destination apparatus.
20. The apparatus of claim 13, wherein: the transceiver is also
configured to exchange one or more messages indicating a
transmission power of the forwarding apparatus and a transmission
power of the apparatus; and the processor is also configured to
determine, based on the transmission power of the forwarding
apparatus and the transmission power of the apparatus, whether it
is preferable to send the data to the destination apparatus via the
forwarding apparatus or to send the data directly to the
destination apparatus.
21. The apparatus of claim 13, wherein: the transceiver is also
configured to exchange one or more messages indicating one or more
beamforming gains of the forwarding apparatus and one or more
beamforming gains of the apparatus; and the processor is also
configured to determine, based on the one or more beamforming gains
of the forwarding apparatus and the one or more beamforming gains
of the apparatus, whether it is preferable to send the data to the
destination apparatus via the forwarding apparatus or to send the
data directly to the destination apparatus.
22. The apparatus of claim 13, wherein the transceiver is also
configured to: transmit a request message to the forwarding
apparatus, and receive, from the forwarding apparatus, a response
message indicating whether the data should be sent directly to the
destination apparatus or forwarded to the destination apparatus via
the forwarding apparatus.
23. The apparatus of claim 13, wherein a portion of the data is
transmitted to the forwarding apparatus to be forwarded to the
destination apparatus before transmitting another portion of the
data to the forwarding apparatus, and wherein the transceiver is
also configured to: receive an acknowledgement from the forwarding
apparatus that the portion of the data is successfully received at
the forwarding apparatus, wherein the portion of the data is not
yet forwarded from the forwarding apparatus to the destination
apparatus.
24. The apparatus of claim 20, wherein the transceiver is also
configured to: receive, from the forwarding apparatus, an
acknowledgement that the portion of the data was successfully
received at the destination apparatus, wherein the destination
apparatus sent the acknowledgment to the forwarding apparatus.
25. An apparatus for wireless communications, comprising: means for
exchanging messages with an apparatus capable of forwarding data to
a destination apparatus; means for determining, based on the
exchange of messages, whether to send data to the destination
apparatus via the forwarding apparatus or to send the data directly
to the destination apparatus; and means for transmitting data to
the destination apparatus based on the determination.
26. The apparatus of claim 25, wherein: the means for exchanging
comprises means for exchanging one or more messages indicating at
least one channel condition; and the means for determining
comprises means for determining, based on the at least one channel
condition, whether it is preferable to send the data to the
destination apparatus via the forwarding apparatus or to send the
data directly to the destination apparatus.
27. The apparatus of claim 26, wherein the at least one channel
condition comprises at least one of: channel condition of a link
between the apparatus and the forwarding apparatus or channel
condition of a link between the forwarding apparatus and the
destination apparatus.
28. The apparatus of claim 25, further comprising: means for
deciding, prior to the transmission based on the determination, to
transmit the data to the destination apparatus via the forwarding
apparatus, wherein the means for transmitting is further configured
to transmit an announcement message about the decision to the
forwarding apparatus.
29. The apparatus of claim 28, wherein the announcement message is
embedded in the data.
30. The apparatus of claim 25, wherein: the means for transmitting
is further configured to transmit the data to the forwarding
apparatus, the data comprising an address of the destination
apparatus, said address indicates that the data should be forwarded
to the destination apparatus.
31. The apparatus of claim 25, wherein: the means for exchanging
comprises means for exchanging one or more messages indicating
directional capability of the forwarding apparatus and directional
capability of the apparatus; and the means for determining
comprises means for determining, based on the directional
capability of the forwarding apparatus and the directional
capability of the apparatus, whether it is preferable to send the
data to the destination apparatus via the forwarding apparatus or
to send the data directly to the destination apparatus.
32. The apparatus of claim 25, wherein: the means for exchanging
comprises means for exchanging one or more messages indicating a
transmission power of the forwarding apparatus and a transmission
power of the apparatus; and the means for determining comprises
means for determining, based on the transmission power of the
forwarding apparatus and the transmission power of the apparatus,
whether it is preferable to send the data to the destination
apparatus via the forwarding apparatus or to send the data directly
to the destination apparatus.
33. The apparatus of claim 25, wherein: the means for exchanging
comprises means for exchanging one or more messages indicating one
or more beamforming gains of the forwarding apparatus and one or
more beamforming gains of the apparatus; and the means for
determining comprises means for determining, based on the one or
more beamforming gains of the forwarding apparatus and the one or
more beamforming gains of the apparatus, whether it is preferable
to send the data to the destination apparatus via the forwarding
apparatus or to send the data directly to the destination
apparatus.
34. The apparatus of claim 25, wherein the means for exchanging
comprises: means for transmitting a request message to the
forwarding apparatus; and means for receiving, from the forwarding
apparatus, a response message indicating whether the data should be
sent directly to the destination apparatus or forwarded to the
destination apparatus via the forwarding apparatus.
35. The apparatus of claim 25, wherein a portion of the data is
transmitted to the forwarding apparatus to be forwarded to the
destination apparatus before transmitting another portion of the
data to the forwarding apparatus, and the apparatus further
comprises: means for receiving an acknowledgement from the
forwarding apparatus that the portion of the data is successfully
received at the forwarding apparatus, wherein the portion of the
data is not yet forwarded from the forwarding apparatus to the
destination apparatus.
36. The apparatus of claim 35, wherein: the means for receiving is
further configured to receive, from the forwarding apparatus, an
acknowledgement that the portion of the data was successfully
received at the destination apparatus, wherein the destination
apparatus sent the acknowledgment to the forwarding apparatus.
37. A computer-program product for wireless communications by a
source apparatus, comprising a computer-readable medium comprising
instructions executable to: exchange messages with an apparatus
capable of forwarding data to a destination apparatus; determine,
based on the exchange of messages, whether to send data to the
destination apparatus via the forwarding apparatus or to send the
data directly to the destination apparatus; and transmit data to
the destination apparatus based on the determination.
38. A wireless node, comprising: at least one antenna; a
transceiver configured to exchange messages, via the at least one
antenna, with another wireless node capable of forwarding data to a
destination wireless node; and a processor configured to determine,
based on the exchange of messages, whether to send data to the
destination wireless node via the forwarding wireless node or to
send the data directly to the destination wireless node, wherein
the transceiver is also configured to transmit data via the at
least one antenna to the destination wireless node based on the
determination.
39. A method for wireless communications by a forwarding apparatus,
comprising: receiving, from a source apparatus, a request message
to send data to a destination apparatus; in response to the request
message, determining whether it is preferable to send the data from
the source apparatus directly to the destination apparatus or to
send the data from the source apparatus to the destination
apparatus via the forwarding apparatus; and transmitting a
confirmation message to the source apparatus and to the destination
apparatus, said confirmation message indicating that it is
preferable to send the data to the destination apparatus via the
forwarding apparatus.
40. The method of claim 39, further comprising: receiving the data
from the source apparatus; and forwarding the received data to the
destination apparatus, and wherein the reception and the forwarding
are performed simultaneously.
41. The method of claim 39, further comprising: receiving the data
from the source apparatus; and forwarding the received data to the
destination apparatus, and wherein all the data are received and
buffered at the forwarding apparatus before being forwarded to the
destination apparatus.
42. The method of claim 39, further comprising: assigning, to the
source apparatus, channel times for transmitting the data from the
source apparatus to the forwarding apparatus; and assigning, to the
destination apparatus, other channel times for receiving the data
at the destination apparatus.
43. The method of claim 39, further comprising: assigning, to the
source apparatus, frequency bands for transmitting the data from
the source apparatus to the forwarding apparatus; and assigning, to
the destination apparatus, other frequency bands for receiving the
data at the destination apparatus.
44. The method of claim 39, further comprising: assigning, to the
source apparatus, a first set of spatial channels for transmitting
the data from the source apparatus to the forwarding apparatus; and
assigning, to the destination apparatus, a second set of spatial
channels for receiving the data at the destination apparatus.
45. The method of claim 39, wherein a portion of the data is
received from the source apparatus and forwarded to the destination
apparatus before receiving another portion of the data from the
source apparatus.
46. The method of claim 45, further comprising: transmitting, to
the source apparatus before forwarding the portion of the data, an
acknowledgement message to acknowledge the reception of the portion
of the data; and receiving, from the destination apparatus, another
acknowledgement message indicating reception of the portion of the
data at the destination apparatus.
47. The method of claim 39, wherein the determination comprises:
determining a first link quality based on channel condition of a
link between the source apparatus and the forwarding apparatus;
determining a second link quality based on channel condition of a
link between the forwarding apparatus and the destination
apparatus; determining a third link quality based on channel
condition of a direct link between the source apparatus and the
destination apparatus; and comparing at least one of the determined
first, second or third link qualities with a defined level of link
quality required for successful transmission of the data using a
selected modulation-coding scheme.
48. The method of claim 47, wherein the channel condition comprises
a signal-to-noise ratio.
49. The method of claim 39, further comprising: receiving the data
from the source apparatus; decoding a portion of the received data;
re-encoding the decoded portion of the data; and forwarding the
re-encoded portion of the data together with a rest of the received
data that was not decoded.
50. The method of claim 49, wherein the decoded portion of the data
comprises a header, and wherein the re-encoding comprises:
modifying the decoded portion of the data.
51. The method of claim 39, further comprising: transmitting, to
the source apparatus, information about at least one channel
condition, wherein the at least one channel condition comprises at
least one of: channel condition of a link between the source
apparatus and the forwarding apparatus or channel condition of a
link between the forwarding apparatus and the destination
apparatus.
52. The method of claim 39, further comprising: receiving, from the
source apparatus, the data comprising an announcement message, said
announcement message indicates that the source apparatus decided to
send the data to the destination apparatus via the forwarding
apparatus.
53. The method of claim 39, further comprising: receiving the data
from the source apparatus, the data comprising an address of the
destination apparatus; and determining, based on the address, that
the received data should be forwarded to the destination
apparatus.
54. An apparatus for wireless communications, comprising: a
receiver configured to receive, from a source apparatus, a request
message to send data to a destination apparatus; a processor
configured to determine, in response to the request message,
whether it is preferable to send the data from the source apparatus
directly to the destination apparatus or to send the data from the
source apparatus to the destination apparatus via the apparatus;
and a transmitter configured to transmit a confirmation message to
the source apparatus and to the destination apparatus, said
confirmation message indicating that it is preferable to send the
data to the destination apparatus via the apparatus.
55. The apparatus of claim 54, wherein: the receiver is also
configured to receive the data from the source apparatus; and the
transmitter is also configured to forward the received data to the
destination apparatus, and wherein the reception and the forwarding
are performed simultaneously.
56. The apparatus of claim 54, wherein: the receiver is also
configured to receive the data from the source apparatus; and the
transmitter is also configured to forward the received data to the
destination apparatus, and wherein all the data are received and
buffered at the apparatus before being forwarded to the destination
apparatus.
57. The apparatus of claim 54, further comprising: a circuit
configured to assign, to the source apparatus, channel times for
transmitting the data from the source apparatus to the apparatus,
wherein the circuit is also configured to assign, to the
destination apparatus, other channel times for receiving the data
at the destination apparatus.
58. The apparatus of claim 54, further comprising: a circuit
configured to assign, to the source apparatus, frequency bands for
transmitting the data from the source apparatus to the apparatus,
wherein the circuit is also configured to assign, to the
destination apparatus, other frequency bands for receiving the data
at the destination apparatus.
59. The apparatus of claim 54, further comprising: a circuit
configured to assign, to the source apparatus, a first set of
spatial channels for transmitting the data from the source
apparatus to the apparatus, wherein the circuit is also configured
to assign, to the destination apparatus, a second set of spatial
channels for receiving the data at the destination apparatus.
60. The apparatus of claim 54, wherein a portion of the data is
received from the source apparatus and forwarded to the destination
apparatus before receiving another portion of the data from the
source apparatus.
61. The apparatus of claim 60, wherein: the transmitter is also
configured to transmit, to the source apparatus before forwarding
the portion of the data, an acknowledgement message to acknowledge
the reception of the portion of the data; and the receiver is also
configured to receive, from the destination apparatus, another
acknowledgement message indicating reception of the portion of the
data at the destination apparatus.
62. The apparatus of claim 54, wherein the processor is also
configured to: determine a first link quality based on channel
condition of a link between the source apparatus and the apparatus;
determine a second link quality based on channel condition of a
link between the apparatus and the destination apparatus; determine
a third link quality based on channel condition of a direct link
between the source apparatus and the destination apparatus; and
compare at least one of the determined first, second or third link
qualities with a defined level of link quality required for
successful transmission of the data using a selected
modulation-coding scheme.
63. The apparatus of claim 62, wherein the channel condition
comprises a signal-to-noise ratio.
64. The apparatus of claim 54, wherein the receiver is also
configured to receive the data from the source apparatus, and the
apparatus further comprising: a decoder configured to decode a
portion of the received data; and an encoder configured to
re-encode the decoded portion of the data, and wherein the
transmitter is also configured to forward the re-encoded portion of
the data together with a rest of the received data that was not
decoded.
65. The apparatus of claim 64, wherein the decoded portion of the
data comprises a header, and wherein the encoder is also configured
to modify the decoded portion of the data.
66. The apparatus of claim 54, wherein: the transmitter is also
configured to transmit, to the source apparatus, information about
at least one channel condition, and wherein the at least one
channel condition comprises at least one of: channel condition of a
link between the source apparatus and the apparatus or channel
condition of a link between the apparatus and the destination
apparatus.
67. The apparatus of claim 54, wherein: the receiver is also
configured to receive, from the source apparatus, the data
comprising an announcement message, said announcement message
indicates that the source apparatus decided to send the data to the
destination apparatus via the apparatus.
68. The apparatus of claim 54, wherein the receiver is also
configured to receive the data from the source apparatus, the data
comprising an address of the destination apparatus, and the
apparatus further comprising: a circuit configured to determine,
based on the address, that the received data should be forwarded to
the destination apparatus.
69. An apparatus for wireless communications, comprising: means for
receiving, from a source apparatus, a request message to send data
to a destination apparatus; means for determining, in response to
the request message, whether it is preferable to send the data from
the source apparatus directly to the destination apparatus or to
send the data from the source apparatus to the destination
apparatus via the apparatus; and means for transmitting a
confirmation message to the source apparatus and to the destination
apparatus, said confirmation message indicating that it is
preferable to send the data to the destination apparatus via the
apparatus.
70. The apparatus of claim 69, wherein: the means for receiving is
further configured to receive the data from the source apparatus;
and the means for transmitting is further configured to forward the
received data to the destination apparatus, and wherein the
reception and the forwarding are performed simultaneously.
71. The apparatus of claim 69, wherein: the means for receiving is
further configured to receive the data from the source apparatus;
and the means for transmitting is further configured to forward the
received data to the destination apparatus, and wherein all the
data are received and buffered at the apparatus before being
forwarded to the destination apparatus.
72. The apparatus of claim 69, further comprising: means for
assigning, to the source apparatus, channel times for transmitting
the data from the source apparatus to the apparatus; and means for
assigning, to the destination apparatus, other channel times for
receiving the data at the destination apparatus.
73. The apparatus of claim 69, further comprising: means for
assigning, to the source apparatus, frequency bands for
transmitting the data from the source apparatus to the apparatus;
and means for assigning, to the destination apparatus, other
frequency bands for receiving the data at the destination
apparatus.
74. The apparatus of claim 69, further comprising: means for
assigning, to the source apparatus, a first set of spatial channels
for transmitting the data from the source apparatus to the
apparatus; and means for assigning, to the destination apparatus, a
second set of spatial channels for receiving the data at the
destination apparatus.
75. The apparatus of claim 69, wherein a portion of the data is
received from the source apparatus and forwarded to the destination
apparatus before receiving another portion of the data from the
source apparatus.
76. The apparatus of claim 75, wherein: the means for transmitting
is further configured to transmit, to the source apparatus before
forwarding the portion of the data, an acknowledgement message to
acknowledge the reception of the portion of the data; and the means
for receiving is further configured to receive, from the
destination apparatus, another acknowledgement message indicating
reception of the portion of the data at the destination
apparatus.
77. The apparatus of claim 69, wherein the means for determining
comprises: means for determining a first link quality based on
channel condition of a link between the source apparatus and the
apparatus; means for determining a second link quality based on
channel condition of a link between the apparatus and the
destination apparatus; means for determining a third link quality
based on channel condition of a direct link between the source
apparatus and the destination apparatus; and means for comparing at
least one of the determined first, second or third link qualities
with a defined level of link quality required for successful
transmission of the data using a selected modulation-coding
scheme.
78. The apparatus of claim 77, wherein the channel condition
comprises a signal-to-noise ratio.
79. The apparatus of claim 69, wherein the means for receiving is
further configured to receive the data from the source apparatus,
and the apparatus further comprising: means for decoding a portion
of the received data; and means for re-encoding the decoded portion
of the data, and wherein the means for transmitting is further
configured to forward the re-encoded portion of the data together
with a rest of the received data that was not decoded.
80. The apparatus of claim 79, wherein the decoded portion of the
data comprises a header, and wherein the means for re-encoding
comprises: means for modifying the decoded portion of the data.
81. The apparatus of claim 69, wherein: the means for transmitting
is further configured to transmit, to the source apparatus,
information about at least one channel condition, and wherein the
at least one channel condition comprises at least one of: channel
condition of a link between the source apparatus and the apparatus
or channel condition of a link between the apparatus and the
destination apparatus.
82. The apparatus of claim 69, wherein: the means for receiving is
further configured to receive, from the source apparatus, the data
comprising an announcement message, said announcement message
indicates that the source apparatus decided to send the data to the
destination apparatus via the apparatus.
83. The apparatus of claim 69, wherein the means for receiving is
further configured to receive the data from the source apparatus,
the data comprising an address of the destination apparatus, and
the apparatus further comprising: means for determining, based on
the address, that the received data should be forwarded to the
destination apparatus.
84. A computer-program product for wireless communications by a
forwarding apparatus, comprising a computer-readable medium
comprising instructions executable to: receive, from a source
apparatus, a request message to send data to a destination
apparatus; in response to the request message, determine whether it
is preferable to send the data from the source apparatus directly
to the destination apparatus or to send the data from the source
apparatus to the destination apparatus via the forwarding
apparatus; and transmit a confirmation message to the source
apparatus and to the destination apparatus, said confirmation
message indicating that it is preferable to send the data to the
destination apparatus via the forwarding apparatus.
85. A wireless node, comprising: at least one antenna; a receiver
configured to receive, from a source wireless node via the at least
one antenna, a request message to send data to a destination
wireless node; a processor configured to determine, in response to
the request message, whether it is preferable to send the data from
the source wireless node directly to the destination wireless node
or to send the data from the source wireless node to the
destination wireless node via the wireless node; and a transmitter
configured to transmit via the at least one antenna a confirmation
message to the source wireless node and to the destination wireless
node, said confirmation message indicating that it is preferable to
send the data to the destination wireless node via the wireless
node.
Description
CLAIM OF PRIORITY UNDER 35 U.S.C. .sctn.119
[0001] The present Application for Patent claims benefit of
Provisional Application Ser. No. 61/255,971 filed Oct. 29, 2009,
and assigned to the assignee hereof and hereby expressly
incorporated by reference herein.
BACKGROUND
[0002] 1. Field
[0003] Certain aspects of the present disclosure generally relate
to a wireless communication and, more particularly, to forwarding
of data in peer-to-peer transactions by a high-capability wireless
device.
[0004] 2. Background
[0005] Handheld/mobile wireless devices often have limited
capabilities compared to access points or other high-end devices,
e.g., in terms of transmission power and beamforming capability.
Furthermore, even if two wireless devices have high capabilities,
the network geometry may be such that the path loss and/or
shadowing in a link between them are very strong.
[0006] Hence, during a peer-to-peer communication between two
mobile stations, these peer stations may not have enough resources
to form a strong link for high-speed communication. This can be
exacerbated in high-frequency links where severe path loss
necessitates the use of directional communication.
SUMMARY
[0007] Certain aspects provide a method for wireless communications
by a source apparatus. The method generally includes exchanging
messages with an apparatus capable of forwarding data to a
destination apparatus, determining, based on the exchange of
messages, whether to send data to the destination apparatus via the
forwarding apparatus or to send the data directly to the
destination apparatus, and transmitting data to the destination
apparatus based on the determination.
[0008] Certain aspects provide an apparatus for wireless
communications. The apparatus generally includes a transceiver
configured to exchange messages with an apparatus capable of
forwarding data to a destination apparatus, and a processor
configured to determine, based on the exchange of messages, whether
to send data to the destination apparatus via the forwarding
apparatus or to send the data directly to the destination
apparatus, wherein the transceiver is also configured to transmit
data to the destination apparatus based on the determination.
[0009] Certain aspects provide an apparatus for wireless
communications. The apparatus generally includes means for
exchanging messages with an apparatus capable of forwarding data to
a destination apparatus, means for determining, based on the
exchange of messages, whether to send data to the destination
apparatus via the forwarding apparatus or to send the data directly
to the destination apparatus, and means for transmitting data to
the destination apparatus based on the determination.
[0010] Certain aspects provide a computer-program product for
wireless communications by a source apparatus. The computer-program
product includes a computer-readable medium comprising instructions
executable to exchange messages with an apparatus capable of
forwarding data to a destination apparatus, determine, based on the
exchange of messages, whether to send data to the destination
apparatus via the forwarding apparatus or to send the data directly
to the destination apparatus, and transmit data to the destination
apparatus based on the determination.
[0011] Certain aspects provide a wireless node. The wireless node
generally includes at least one antenna, a transceiver configured
to exchange messages via the at least one antenna with another
wireless node capable of forwarding data to a destination wireless
node, and a processor configured to determine, based on the
exchange of messages, whether to send data to the destination
wireless node via the forwarding wireless node or to send the data
directly to the destination wireless node, wherein the transceiver
is also configured to transmit data via the at least one antenna to
the destination apparatus based on the determination.
[0012] Certain aspects provide a method for wireless communications
by a forwarding apparatus. The method generally includes receiving,
from a source apparatus, a request message to send data to a
destination apparatus, in response to the request message,
determining whether it is preferable to send the data from the
source apparatus directly to the destination apparatus or to send
the data from the source apparatus to the destination apparatus via
the forwarding apparatus, and transmitting a confirmation message
to the source apparatus and to the destination apparatus, said
confirmation message indicating that it is preferable to send the
data to the destination apparatus via the forwarding apparatus.
[0013] Certain aspects provide an apparatus for wireless
communications. The apparatus generally includes a receiver
configured to receive, from a source apparatus, a request message
to send data to a destination apparatus, a processor configured to
determine, in response to the request message, whether it is
preferable to send the data from the source apparatus directly to
the destination apparatus or to send the data from the source
apparatus to the destination apparatus via the apparatus, and a
transmitter configured to transmit a confirmation message to the
source apparatus and to the destination apparatus, said
confirmation message indicating that it is preferable to send the
data to the destination apparatus via the apparatus.
[0014] Certain aspects provide an apparatus for wireless
communications. The apparatus generally includes means for
receiving, from a source apparatus, a request message to send data
to a destination apparatus, means for determining, in response to
the request message, whether it is preferable to send the data from
the source apparatus directly to the destination apparatus or to
send the data from the source apparatus to the destination
apparatus via the apparatus, and means for transmitting a
confirmation message to the source apparatus and to the destination
apparatus, said confirmation message indicating that it is
preferable to send the data to the destination apparatus via the
apparatus.
[0015] Certain aspects provide a computer-program product for
wireless communications by a forwarding apparatus. The
computer-program product includes a computer-readable medium
comprising instructions executable to receive, from a source
apparatus, a request message to send data to a destination
apparatus, in response to the request message, determine whether it
is preferable to send the data from the source apparatus directly
to the destination apparatus or to send the data from the source
apparatus to the destination apparatus via the forwarding
apparatus, and transmit a confirmation message to the source
apparatus and to the destination apparatus, said confirmation
message indicating that it is preferable to send the data to the
destination apparatus via the forwarding apparatus.
[0016] Certain aspects provide a wireless node. The wireless node
generally includes at least one antenna, a receiver configured to
receive, from a source wireless node via the at least one antenna,
a request message to send data to a destination wireless node, a
processor configured to determine, in response to the request
message, whether it is preferable to send the data from the source
wireless node directly to the destination wireless node or to send
the data from the source wireless node to the destination wireless
node via the wireless node, and a transmitter configured to
transmit via the at least one antenna a confirmation message to the
source wireless node and to the destination wireless node, said
confirmation message indicating that it is preferable to send the
data to the destination wireless node via the wireless node.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] So that the manner in which the above-recited features of
the present disclosure can be understood in detail, a more
particular description, briefly summarized above, may be had by
reference to aspects, some of which are illustrated in the appended
drawings. It is to be noted, however, that the appended drawings
illustrate only certain typical aspects of this disclosure and are
therefore not to be considered limiting of its scope, for the
description may admit to other equally effective aspects.
[0018] FIG. 1 illustrates an example wireless communication system
in accordance with certain aspects of the present disclosure.
[0019] FIG. 2 illustrates a system that allows two nodes to
communicate in accordance with certain aspects of the present
disclosure.
[0020] FIG. 3 illustrates an example of a communication device in
accordance with certain aspects of the present disclosure.
[0021] FIG. 4 illustrates an example wireless network with wide
beam patterns at mobile stations (STAs) and antenna arrays with
fine beam patterns at an access point (AP) in accordance with
certain aspects of the present disclosure.
[0022] FIG. 5 illustrates example operations executed at a STA
which may transmit data to the AP to be forwarded to another STA in
accordance with certain aspects of the present disclosure.
[0023] FIG. 5A illustrates example components capable of performing
the operations illustrated in FIG. 5.
[0024] FIG. 6 illustrates example operations executed at the AP
which may forward the data received from the STA to the other STA
in accordance with certain aspects of the present disclosure.
[0025] FIG. 6A illustrates example components capable of performing
the operations illustrated in FIG. 6.
DETAILED DESCRIPTION
[0026] Various aspects of the disclosure are described more fully
hereinafter with reference to the accompanying drawings. This
disclosure may, however, be embodied in many different forms and
should not be construed as limited to any specific structure or
function presented throughout this disclosure. Rather, these
aspects are provided so that this disclosure will be thorough and
complete, and will fully convey the scope of the disclosure to
those skilled in the art. Based on the teachings herein, one
skilled in the art should appreciate that the scope of the
disclosure is intended to cover any aspect of the disclosure
disclosed herein, whether implemented independently of or combined
with any other aspect of the disclosure. For example, an apparatus
may be implemented or a method may be practiced using any number of
the aspects set forth herein. In addition, the scope of the
disclosure is intended to cover such an apparatus or method which
is practiced using other structure, functionality, or structure and
functionality in addition to or other than the various aspects of
the disclosure set forth herein. It should be understood that any
aspect of the disclosure disclosed herein may be embodied by one or
more elements of a claim.
[0027] The word "exemplary" is used herein to mean "serving as an
example, instance, or illustration." Any aspect described herein as
"exemplary" is not necessarily to be construed as preferred or
advantageous over other aspects.
[0028] Although particular aspects are described herein, many
variations and permutations of these aspects fall within the scope
of the disclosure. Although some benefits and advantages of the
preferred aspects are mentioned, the scope of the disclosure is not
intended to be limited to particular benefits, uses or objectives.
Rather, aspects of the disclosure are intended to be broadly
applicable to different wireless technologies, system
configurations, networks, and transmission protocols, some of which
are illustrated by way of example in the figures and in the
following description of the preferred aspects. The detailed
description and drawings are merely illustrative of the disclosure
rather than limiting, the scope of the disclosure being defined by
the appended claims and equivalents thereof.
An Example Wireless Communication System
[0029] The techniques described herein may be used for various
broadband wireless communication systems, including communication
systems that are based on an orthogonal multiplexing scheme.
Examples of such communication systems include Orthogonal Frequency
Division Multiple Access (OFDMA) systems, Single-Carrier Frequency
Division Multiple Access (SC-FDMA) systems, and so forth. An OFDMA
system utilizes orthogonal frequency division multiplexing (OFDM),
which is a modulation technique that partitions the overall system
bandwidth into multiple orthogonal sub-carriers. These sub-carriers
may also be called tones, bins, etc. With OFDM, each sub-carrier
may be independently modulated with data. An SC-FDMA system may
utilize interleaved FDMA (IFDMA) to transmit on sub-carriers that
are distributed across the system bandwidth, localized FDMA (LFDMA)
to transmit on a block of adjacent sub-carriers, or enhanced FDMA
(EFDMA) to transmit on multiple blocks of adjacent sub-carriers. In
general, modulation symbols are sent in the frequency domain with
OFDM and in the time domain with SC-FDMA.
[0030] One specific example of a communication system based on an
orthogonal multiplexing scheme is a WiMAX system. WiMAX, which
stands for the Worldwide Interoperability for Microwave Access, is
a standards-based broadband wireless technology that provides
high-throughput broadband connections over long distances. There
are two main applications of WiMAX today: fixed WiMAX and mobile
WiMAX. Fixed WiMAX applications are point-to-multipoint, enabling
broadband access to homes and businesses, for example. Mobile WiMAX
offers the full mobility of cellular networks at broadband
speeds.
[0031] IEEE 802.16x is an emerging standard organization to define
an air interface for fixed and mobile broadband wireless access
(BWA) systems. IEEE 802.16x approved "IEEE P802.16d/D5-2004" in May
2004 for fixed BWA systems and published "IEEE P802.16e/D12 October
2005" in October 2005 for mobile BWA systems. The latest revision
of the IEEE 802.16, "IEEE P802.16Rev2/D8 December 2008," a draft
standard, now consolidates materials from IEEE 802.16e and
corrigendum. The standards define four different physical layers
(PHYs) and one medium access control (MAC) layer. The OFDM and
OFDMA physical layer of the four physical layers are the most
popular in the fixed and mobile BWA areas respectively.
[0032] The teachings herein may be incorporated into (e.g.,
implemented within or performed by) a variety of wired or wireless
apparatuses (e.g., nodes). In some aspects, a node implemented in
accordance with the teachings herein may comprise an access point
or an access terminal.
[0033] An access point ("AP") may comprise, be implemented as, or
known as NodeB, Radio Network Controller ("RNC"), eNodeB, Base
Station Controller ("BSC"), Base Transceiver Station ("BTS"), Base
Station ("BS"), Transceiver Function ("TF"), Radio Router, Radio
Transceiver, Basic Service Set ("BSS"), Extended Service Set
("ESS"), Radio Base Station ("RBS"), or some other terminology.
[0034] An access terminal ("AT") may comprise, be implemented as,
or known as an access terminal, a subscriber station, a subscriber
unit, a mobile station, a remote station, a remote terminal, a user
terminal, a user agent, a user device, user equipment, or some
other terminology. In some implementations an access terminal may
comprise a cellular telephone, a 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 some other suitable
processing device connected to a wireless modem. Accordingly, one
or more aspects taught herein may be incorporated into a phone
(e.g., a cellular phone or smart phone), a computer (e.g., a
laptop), a portable communication device, a portable computing
device (e.g., a personal data assistant), an entertainment device
(e.g., a music or video device, or a satellite radio), a global
positioning system device, a headset, a sensor or any other
suitable device that is configured to communicate via a wireless or
wired medium. In some aspects the node is a wireless node. Such
wireless node may provide, for example, connectivity for or to a
network (e.g., a wide area network such as the Internet or a
cellular network) via a wired or wireless communication link.
[0035] Referring now to FIG. 1, illustrated is a wireless
communication system 100 in accordance with various aspects of the
present disclosure. System 100 comprises a base station (i.e., an
access point) 102 that can include multiple antenna groups. For
example, one antenna group can include antennas 104 and 106,
another group can comprise antennas 108 and 110, and an additional
group can include antennas 112 and 114. Two antennas are
illustrated for each antenna group; however, more or fewer antennas
can be utilized for each group. The base station 102 can
additionally include a transmitter chain and a receiver chain, each
of which can in turn comprise a plurality of components associated
with signal transmission and reception (e.g., processors,
modulators, multiplexers, demodulators, demultiplexers, antennas,
and so forth), as will be appreciated by one skilled in the art.
Additionally, the base station 102 can be a home base station, a
Femto base station, and/or the like.
[0036] The base station 102 can communicate with one or more
devices such as device 116; however, it is to be appreciated that
base station 102 can communicate with substantially any number of
devices similar to device 116. As depicted, device 116 is in
communication with antennas 104 and 106, where antennas 104 and 106
transmit information to device 116 over a forward link 118 and
receive information from device 116 over a reverse link 120. In a
frequency division duplex (FDD) system, forward link 118 can
utilize a different frequency band than that used by reverse link
120, for example. Further, in a time division duplex (TDD) system,
forward link 118 and reverse link 120 can utilize a common
frequency band.
[0037] In addition, devices 122 and 124 can be communicating with
one another, such as in a peer-to-peer configuration. Moreover,
device 122 is in communication with device 124 using links 126 and
128. In a peer-to-peer ad hoc network, devices within range of each
other, such as devices 122 and 124, communicate directly with each
other without a base station 102 and/or a wired infrastructure to
relay their communication. Additionally, peer devices or nodes can
relay traffic. The devices within the network communicating in a
peer-to-peer manner can function similar to base stations and relay
traffic or communications to other devices, functioning similar to
base stations, until the traffic reaches its ultimate destination.
The devices can also transmit control channels, which carry
information that can be utilized to manage the data transmission
between peer nodes.
[0038] A communication network can include any number of devices or
nodes that are in wireless (or wired) communication. Each node can
be within range of one or more other nodes and can communicate with
the other nodes or through utilization of the other nodes, such as
in a multi-hop topography (e.g., communications can hop from node
to node until reaching a final destination). For example, a sender
node may wish to communicate with a receiver node. To enable packet
transfer between sender node and receiver node, one or more
intermediate nodes can be utilized. It should be understood that
any node can be a sender node and/or a receiver node and can
perform functions of either sending and/or receiving information at
substantially the same time (e.g., can broadcast or communicate
information at about the same time as receiving information) or at
different times.
[0039] System 100 can be configured to allow nodes that have
initiated a communication session over a network to move the
session to a direct connection. Nodes that are directly connected
can exchange packets natively without any encapsulation. In
accordance with some aspects, a "homeless" node can switch to a
wireless network without losing its ongoing sessions. By "homeless"
it is meant a node that does not have any home agent entity to
provide assistance for keeping ongoing sessions alive while
switching to foreign networks nor to forward any new incoming
request(s) to establish new sessions to the node's current
location. In accordance with some aspects, nodes can be mobile
(e.g., wireless), static (e.g., wired), or combinations thereof
(e.g., one node static and a second node mobile, both nodes mobile,
and so forth).
[0040] FIG. 2 illustrates a system 200 that allows two nodes to
communicate over a Wide Area Network interface and/or a Device to
Device interface, according to various aspects. Included in the
system 200 are a first node (Node.sub.1) 202 and a second node
(Node.sub.2) 204. Each node 202, 204 includes at least two
interfaces. A first interface can be connected to a network 206
that provides Internet Protocol (IP) addresses. For example, the
network can be a Wide Area Network (WAN), a Local Area Network
(LAN), a home network, Digital Subscriber Line (DSL), cable, 3GPP
based, 3GPP2 based, or any other technology providing
interconnectivity and routing to a network of interest (e.g., the
Internet).
[0041] Interfaces of nodes 202 and 204 can be wired (e.g., Device
to Device), wireless (e.g., WAN), or combinations thereof. For
example, Node.sub.1 interface can be wireless and Node.sub.2
interface can be wired, or Node.sub.2 interface can be wireless and
Node.sub.1 interface can be wired, both interfaces can be wireless,
or both interfaces can be wired.
[0042] For illustration purposes, the first interface of each node
202, 204 is a WAN interface, 208 and 210. WAN interfaces 208, 210
provide a connection over network 206, illustrated by links 212 and
214. Further, each node 202, 204 includes at least a second
interface that is connected to a local network with directly
connected peers or a multi-hop mesh network. For example, the local
network can be a Wireless Local Area Network (WLAN) or another
device to device (e.g., peer to peer) technology. For illustration
purposes, the second interface of each node 202, 204 is illustrated
as a Device to Device (D2D) interface 216, 218. The D2D interfaces
216, 218 allow nodes 202, 204 to perform direct communications,
illustrated by direct link 220.
[0043] A procedure according to various aspects for starting a
session over network 206 and moving to a direct session (e.g., over
direct link 220) will now be described. For example purposes, it is
assumed that Node.sub.1 202 utilizes Mobile Internet Protocol.
Communications are performed by Node.sub.1 202 utilizing its Mobile
IP home address as a source address. A home address is a unicast
routable address assigned to a node and is used as the permanent
address of the node. Node.sub.1 202 communicates with Node.sub.2
204 over network 206 (e.g., WAN) by sending and receiving packets
over respective first interfaces (e.g., WAN interfaces 208, 210).
The packets can be encapsulated in a MIPv6 tunnel to a home agent,
which can be included in network 206 according to various aspects,
or a route optimization tunnel directly to Node.sub.2 204.
[0044] FIG. 3 illustrates an exemplary first communications device
300, in accordance with an exemplary aspect. Exemplary first
communications device 300 is, e.g., one of the wireless
communications devices (102, 116, 122, 124) of FIG. 1 or one of the
wireless communications devices (202, 204) of FIG. 2.
[0045] First communications device 300 includes a processor 302 and
memory 304 coupled together via a bus 309 over which the various
elements (302, 304) may interchange data and information.
Communications device 300 further includes an input module 306 and
an output module 308 which may be coupled to processor 302 as
shown. However, in some aspects, the input module 306 and output
module 308 are located internal to the processor 302. Input module
306 can receive input signals. Input module 306 can, and in some
aspects does, include a wireless receiver and/or a wired or optical
input interface for receiving input. Output module 308 may include,
and in some aspects does include, a wireless transmitter and/or a
wired or optical output interface for transmitting output.
[0046] Processor 302 is configured to: receive a first signal from
a second communications device; generate a first application alert
if said first signal satisfies an application alert criteria; and
receive a second signal from an access point said second signal
carrying second communications device information based on a
previous signal from the second communications device. The access
point may be, and sometimes is, a base station. In some aspects,
the second communications device information is location
information. In various aspects, processor 302 is configured to
receive said first signal via a wireless peer to peer interface as
part of being configured to receive a first signal. In some
aspects, processor 302 is configured to receive the second signal
via a wireless wide area network interface as part of being
configured to receive the second signal.
[0047] Processor 302 is further configured to determine an
operation to take based on the second communications device
information included in the second signal and information included
in said first signal. In one exemplary aspect, said second
communications device information included in the second signal is
information on a previous location of said second communications
device, said information included in the first signal is current
location information, and said operation is one of a location based
traffic update operation and a location based advertisement update
operation. Processor 302, in some aspects, is further configured to
send an information request signal to the access point requesting
information corresponding to the second communications device, in
response to the generated first application alert.
[0048] Certain aspects of the present disclosure support the
mechanism for an access point (AP), such as the AP 102 from FIG. 1,
or another high-capability wireless device to forward traffic from
one device (i.e., peer) to another, such as from the device 122 to
the device 124. Criteria are also proposed in the present
disclosure to decide when forwarding via the AP is advantageous
over direct peer-to-peer communication.
Problem Setting
[0049] Due to the severe path loss in high frequency wireless
networks, such as those operating in the 60 GHz band, these systems
are expected to rely heavily on directional communication.
According to the Friis equation:
P RX = G TX G RX c 2 ( 4 .pi. d ) 2 f c 2 .times. 1 .sigma. N f P
TX , ( 1 ) ##EQU00001##
the received power (and hence the received signal-to-noise ratio
(SNR)) may be proportional to the product of antenna gains at a
transmitter and a receiver, G.sub.TX and G.sub.RX, respectively.
P.sub.TX in equation (1) denotes a transmission power, d is a
distance between the transmitter and receiver, c is a speed of a
transmission signal, and f.sub.c is a carrier frequency.
[0050] Having a plugged-in power supply and the ability to support
higher processing power (compared to mobile and handheld devices)
makes it possible for the APs to use large arrays of antennas. Such
APs may obtain very large antenna gains when using beamforming to
steer a narrow beam towards a user station (STA). On the other
hand, cost, space and power limitations may prevent handheld and/or
portable STAs from having many antenna elements, or using
complicated beamforming algorithms.
[0051] When a handheld STA communicates with an AP, a relatively
small antenna gain of the STA in equation (1) may be compensated by
a high antenna gain of the AP. However, when two handheld STAs with
limited beamforming capabilities communicate directly in a
peer-to-peer manner, the resulting weak link budget may severely
limit the throughput of the STA-to-STA link. Furthermore, each of
the two STAs may be more likely to have a line of sight (LOS) path
to the AP, since APs may be mounted on higher points such as the
ceiling, while the direct path between the two STAs may be
obstructed by an obstacle, such as a wall or smaller objects. An
example of such scenarios is in an office space with cubicles,
where the STAs often do not mutually have a LOS, while each of them
may have a LOS to the AP installed on the ceiling.
[0052] In another scenario, two STAs may be located at two far ends
of a wireless network, such that the path loss between them may be
too strong to perform high-throughput communication. A third STA,
possible the AP, may be positioned such that the path loss from
each of the two stations to the third station may be much smaller
than the path loss between the two STAs. An example of such a
situation is a home network in a house, where the set-up box and
the TV may be placed in the two far ends of the house, but there
may be an AP midway between them.
[0053] In the abovementioned scenarios, the link between two STAs
may have a significantly lower capacity than that between the
AP/third STA and each of the two STAs. Hence, when the two STAs
need to communicate, it may be more beneficial for the AP/third STA
to forward the traffic between them, instead of the two STAs
communicating directly.
Criteria for Forwarding of Peer-To-Peer Traffic
[0054] FIG. 4 illustrates an example wireless network with wide
beam patterns at mobile stations and antenna arrays with fine beam
patterns at an access point (AP) in accordance with certain aspects
of the present disclosure. A station (STA) 402 may intend to
transmit data to another STA 404. The signal-to-noise ratio (SNR)
observed at a direct link 408 from the STA 402 to the STA 404 can
be denoted by SNR.sub.0, and the SNRs observed at a link 410 from
the STA 402 to the AP 406 and at a link 412 from the AP 406 to the
STA 404 can be denoted respectively by SNR.sub.1 and SNR.sub.2,
defined per complex dimension. At each of these links, the best
possible transmit and receive beam patterns may be utilized.
[0055] Several conditions may be met, such as: SNR.sub.0 may be too
low to support a high throughput transmission from the STA 402 to
the STA 404, SNR.sub.1 and SNR.sub.2 may be both much higher than
SNR.sub.0, and the traffic may tolerate the additional latency of
communicating through the AP 406. In this case, the STA 402 may
transmit data to the AP 406 instead of sending them directly to the
STA 404, and then the AP 406 may forward the data to the STA
404.
[0056] Through earlier negotiations, the AP 406 and/or the STA 402
may be aware of the values of SNR.sub.0, SNR.sub.1, and SNR.sub.2.
Furthermore, the channels may be relatively stationary, such that
the SNRs do not vary significantly during the intended
communication. Using Shannon's formula for the capacity of an
Additive White Gaussian Noise (AWGN) channel, the spectral
efficiency of the complex channels 408, 410, and 412 may be denoted
respectively by C.sub.0, C.sub.1, and C.sub.2, and computed as:
C.sub.i=log.sub.2(1+SNR.sub.i) bits/sec/Hz (2)
[0057] During the forwarding, successful transmission of a data
packet from the STA 402 to the AP 406 may need to be completed
before it is forwarded from the AP 406 to the STA 404. Furthermore,
the transmitted data packets may be long, so that the channel time
used for the transmission may be proportional to the packet length,
rather than being dominated by the overheads, processing times and
signal travel time between the transmitter and the receiver.
[0058] The channel time used for transmitting a data packet through
a channel with capacity C.sub.i may be approximated as:
T i = .alpha. C i , ( 3 ) ##EQU00002##
where .alpha. is a constant which is a function of the packet
length and system specifications. In order to decide whether AP
forwarding is beneficial, a total channel time used by direct
transmission T.sub.D may be compared versus a channel time used for
forwarding T.sub.FW. By combining equations (2) and (3), T.sub.D
and T.sub.FW may be estimated as:
T D = .alpha. log ( 1 + SNR 0 ) , T FW = .alpha. log ( 1 + SNR 1 )
+ .alpha. log ( 1 + SNR 2 ) . ( 4 ) ##EQU00003##
[0059] Furthermore, since the list of possible modulation and
coding schemes (MCSs) are often defined by a wireless standard, the
minimum SNR value required for successful transmission of the data
packet using the most reliable MCS among the defined MCSs may need
to be considered. This particular SNR value can be denoted by
SNR.sub.min.
[0060] By summarizing the discussion above, a protocol is proposed
for the AP (or for the other high capability device) to decide
between direct transmission and AP forwarding. The AP (e.g., the AP
406 from FIG. 4) may first obtain SNR values SNR.sub.0, SNR.sub.1,
and SNR.sub.2 of the links 408, 410, and 412, respectively. If
SNR.sub.0<SNR.sub.min, but SNR.sub.1>SNR.sub.min and
SNR.sub.2>SNR.sub.min, then the AP forwarding may be chosen. If
SNR.sub.0>SNR.sub.min, but either SNR.sub.1<SNR.sub.min or
SNR.sub.2<SNR.sub.min, then the direct transmission from the STA
402 to the STA 404 may be selected. If SNR.sub.0<SNR.sub.min,
SNR.sub.1<SNR.sub.min, and SNR.sub.2<SNR.sub.min, then
reliable transmission may not be possible using either scheme.
If:
T D .alpha. = 1 log ( 1 + SNR 0 ) .ltoreq. 1 log ( 1 + SNR 1 ) + 1
log ( 1 + SNR 2 ) = T FW .alpha. , ( 5 ) ##EQU00004##
then the direct communication may be chosen. Otherwise, the AP
forwarding may be selected.
Protocol for Forwarding of Peer-To-Peer Traffic
[0061] AP forwarding capability may be announced periodically by an
AP using an information element (IE) within a beacon or within
other control messages. Forwarding capable STA may announce the
forwarding capability in its association messages. The decision for
considering the AP forwarding as an option may be taken by the
higher layer sections of the source STA (e.g., the STA 402 from
FIG. 4) or the AP, based on the link quality, traffic type and
other considerations. The forwarding process may be mostly
transparent to the Physical layer (PHY) and Media Access Control
(MAC) layer of a destination STA (e.g., the STA 404 from FIG. 4).
The STA 404 may perform its reception and acknowledgement as though
it is communicating only with the AP.
[0062] Once either the STA 402 or the AP 406 decides to consider AP
forwarding as an option and if all the involving STAs support AP
forwarding, then the following protocol can be utilized to perform
data communication between two peer stations. When the STA 402
decides to consider AP forwarding as an option, it may send a
forwarding request message to the AP 406. In one aspect of the
present disclosure, the STA 402 may transmit the forwarding request
message using its preferred antenna pattern. This request may also
contain various traffic parameters. In another aspect of the
present disclosure, the STA 402 may send the forwarding request to
both the AP 406 and the STA 404 by using its omni beam. The AP 406
may acknowledge the receipt and acceptance of the forwarding
request by sending an AP forwarding request acknowledgement to the
STA 402.
[0063] The AP 406 may perform the previously proposed method to
decide whether the AP forwarding is preferable to direct
communication between the STA 402 and the STA 404. If the direct
communication is preferable, then the AP 406 may transmit an AP
forwarding denial message to the STA 402, and the forwarding
protocol may be terminated. On the other hand, if the AP forwarding
is chosen by the AP 406, then the AP may transmit an AP forwarding
confirmation message to the STA 402 and to the STA 404, announcing
that the AP may forward some traffic from the STA 402 to the STA
404.
[0064] In one aspect of the present disclosure, the AP 406 may
assign channel times for the STA 402 to transmit some of its
packets to the AP 406, as well as other channel times for the STA
404 to receive the forwarded packets from the AP 406. In another
aspect, the AP 406 may assign particular frequency bands for data
transmission between the STA 402 and the AP 406, and other possibly
different frequency bands for data reception at the STA 404. In yet
another aspect, the AP 406 may allocate a set of spatial channels
for data transmission between the STA 402 and the AP 406, and
another set of spatial channels for forwarding data from the AP 406
to the STA 404.
[0065] The forwarding may be performed in one hop, i.e., the STA
402 may send all the data, the AP 406 may receive and buffer them,
and then the AP 406 may forward all of the data to the STA 404.
Alternatively, the forwarding may be performed in multiple hops,
i.e., data packets may be transmitted and forwarded in multiple
cycles.
[0066] In one aspect of the present disclosure, the AP 406 may
decode the entire data packet received from the STA 402, then
re-encode it, and finally transmit it to the STA 404. During the
re-encoding, some changes to a header of the data packet may be
applied. In another aspect, the AP 406 may decode only a part
(e.g., a header) of the data packet received from the STA 402. The
decoded part may be then re-encoded, possibly with some changes
applied to its content. A rest of the packet (i.e., a part of the
packet that is not decoded) may be only down-converted and then
up-converted at the AP 406 before being forwarded to the STA 404.
This remaining part of the packet may be transmitted from the AP
406 to the STA 404 together with the re-encoded part of the
packet.
[0067] In yet another aspect of the present disclosure, the AP 406
may forward the data packet received from the STA 402 without
decoding and re-encoding any portion of the packet. Instead, the AP
406 may only up-convert the received down-converted data samples,
and then transmit them to the STA 404. The data transmission from
the AP 406 to the STA 404 may be performed in real time (i.e.,
simultaneously with the reception of data at the AP 406 with a
defined small delay). Alternatively, the data transmission from the
AP 406 to the STA 404 may be performed in a separate time period
from the data reception at the AP 406. In this case, the entire
packet may be first buffered at the AP 406 before being forwarded
to the STA 404.
[0068] The acknowledgement process of each packet may be completed
between the AP 406 and the STA 402, similar to a regular data
exchange, before the packet is being forwarded to the STA 404.
Similarly, the STA 404 may perform its acknowledgement process with
the AP 406, and not with the STA 402. Certain aspects of the
present disclosure support that the acknowledgement from the STA
404 is being forwarded to the STA 402 by the AP 406. This may
remove the requirement of buffering the packets at the AP 406
received from the STA 402.
[0069] In one aspect of the present disclosure, the AP 406 may
inform at least one STA is the network, including the STA 402, of
channel conditions of links between the AP 406 and a plurality of
STAs in the network. Therefore, the AP 406 may inform the STA 402
about channel condition of the link between the AP 406 and the STA
402, as well as about channel condition of the link between the AP
406 and the STA 404. Based on this information and known channel
condition of the direct link between the STA 402 and the STA 404,
the STA 402 may determine whether it is preferable to send the data
to the STA 404 via the AP 406 or to send the data directly to the
STA 404.
[0070] Based on this determination, the STA 402 may decide to send
the data to the STA 404 via the AP 406. In this case, the STA 402
may send a request or an announcement message to the AP 406 about
the decision. The announcement message may be embedded in the data
to be forwarded to the STA 404 by the AP 406. Alternatively,
instead of sending the additional message about the decision to
send the data to the STA 404 via the AP 406, the STA 402 may
include an indication within the data that final destination for
the data is the STA 404. The indication may comprise an address of
the STA 404. Once receiving the data, the AP 406 may know to
forward the received data to the STA 404 based on the indication
embedded in the received data.
[0071] FIG. 5 illustrates example operations 500 executed at a
source apparatus that may transmit data to an apparatus capable of
forwarding data to a destination apparatus in accordance with
certain aspects of the present disclosure. The source apparatus may
be the STA 402 from FIG. 4, the forwarding apparatus may be the AP
406 and the destination apparatus may be the STA 404. At 502, the
source apparatus may exchange messages with the forwarding
apparatus. At 504, it may be determined, based on the exchange of
messages, whether to send data to the destination apparatus via the
forwarding apparatus or to send the data directly to the
destination apparatus. At 506, the source apparatus may transmit
data to the destination apparatus based on the determination.
[0072] In one aspect of the present disclosure, the exchanging of
messages may comprise exchanging one or more messages indicating
directional capability of the forwarding apparatus and directional
capability of the source apparatus. Then, based on the directional
capability of the forwarding apparatus and the directional
capability of the source apparatus, it may be determined (either at
the forwarding apparatus or at the source apparatus) whether it is
preferable to forward the data to the destination apparatus via the
forwarding apparatus or to send the data directly to the
destination apparatus.
[0073] In another aspect of the present disclosure, the exchanging
of messages may comprise exchanging one or more messages indicating
a transmission power of the forwarding apparatus and a transmission
power of the source apparatus. Then, based on the transmission
power of the forwarding apparatus and the transmission power of the
source apparatus, it may be determined (either at the forwarding
apparatus or at the source apparatus) whether it is preferable to
forward the data to the destination apparatus via the forwarding
apparatus or to send the data directly to the destination
apparatus.
[0074] In yet another aspect of the present disclosure, the
exchanging of messages may comprise exchanging one or more messages
indicating one or more beamforming gains of the forwarding
apparatus and of the source apparatus. Then, based on the one or
more beamforming gains of the forwarding apparatus and of the
source apparatus, it may be determined (either at the forwarding
apparatus or at the source apparatus) whether it is preferable to
forward the data to the destination apparatus via the forwarding
apparatus or to send the data directly to the destination
apparatus.
[0075] FIG. 6 illustrates example operations 600 executed at the
forwarding apparatus which may forward the data from the source
apparatus to the destination apparatus in accordance with certain
aspects of the present disclosure. At 602, the forwarding apparatus
may receive from the source apparatus a request message to send the
data to the destination apparatus. At 604, in response to the
request message, the forwarding apparatus may determine whether it
is preferable to send the data from the source apparatus directly
to the destination apparatus or to send the data from the source
apparatus to the destination apparatus via the forwarding
apparatus. At 606, the forwarding apparatus may transmit a
confirmation message to the source apparatus and to the destination
apparatus, said confirmation message indicating that it is
preferable to send the data to the destination apparatus via the
forwarding apparatus. In response to the confirmation message, the
source apparatus may transmit the data to the forwarding apparatus,
and then the data may be forwarded from the forwarding apparatus to
the destination apparatus.
[0076] The various operations of methods described above may be
performed by any suitable means capable of performing the
corresponding functions. The means may include various hardware
and/or software component(s) and/or module(s), including, but not
limited to a circuit, an application specific integrate circuit
(ASIC), or processor. Generally, where there are operations
illustrated in Figures, those operations may have corresponding
counterpart means-plus-function components with similar numbering.
For example, blocks 502-506 and 602-606 illustrated in FIG. 5 and
FIG. 6, correspond to circuit blocks 502A-506A and 602A-606A
illustrated in FIG. 5A and FIG. 6A.
[0077] As used herein, the term "determining" encompasses a wide
variety of actions. For example, "determining" may include
calculating, computing, processing, deriving, investigating,
looking up (e.g., looking up in a table, a database or another data
structure), ascertaining and the like. Also, "determining" may
include receiving (e.g., receiving information), accessing (e.g.,
accessing data in a memory) and the like. Also, "determining" may
include resolving, selecting, choosing, establishing and the
like.
[0078] As used herein, a phrase referring to "at least one of a
list of items refers to any combination of those items, including
single members. As an example, "at least one of: a, b, or c" is
intended to cover: a, b, c, a-b, a-c, b-c, and a-b-c.
[0079] The various operations of methods described above may be
performed by any suitable means capable of performing the
operations, such as various hardware and/or software component(s),
circuits, and/or module(s). Generally, any operations illustrated
in the Figures may be performed by corresponding functional means
capable of performing the operations.
[0080] The various illustrative logical blocks, modules and
circuits described in connection with the present disclosure may be
implemented or performed with a general purpose processor, a
digital signal processor (DSP), an application specific integrated
circuit (ASIC), a field programmable gate array signal (FPGA) or
other programmable logic device (PLD), discrete gate or transistor
logic, discrete hardware components or any combination thereof
designed to perform the functions described herein. A general
purpose processor may be a microprocessor, but in the alternative,
the processor may be any commercially available processor,
controller, microcontroller or state machine. A processor may also
be implemented as a combination of computing devices, e.g., a
combination of a DSP and a microprocessor, a plurality of
microprocessors, one or more microprocessors in conjunction with a
DSP core, or any other such configuration.
[0081] The steps of a method or algorithm described in connection
with the present disclosure may be embodied directly in hardware,
in a software module executed by a processor, or in a combination
of the two. A software module may reside in any form of storage
medium that is known in the art. Some examples of storage media
that may be used include random access memory (RAM), read only
memory (ROM), flash memory, EPROM memory, EEPROM memory, registers,
a hard disk, a removable disk, a CD-ROM and so forth. A software
module may comprise a single instruction, or many instructions, and
may be distributed over several different code segments, among
different programs, and across multiple storage media. A storage
medium may be coupled to a processor such that the processor can
read information from, and write information to, the storage
medium. In the alternative, the storage medium may be integral to
the processor.
[0082] The methods disclosed herein comprise one or more steps or
actions for achieving the described method. The method steps and/or
actions may be interchanged with one another without departing from
the scope of the claims. In other words, unless a specific order of
steps or actions is specified, the order and/or use of specific
steps and/or actions may be modified without departing from the
scope of the claims.
[0083] The functions described may be implemented in hardware,
software, firmware or any combination thereof If implemented in
software, the functions may be stored as one or more instructions
on a computer-readable medium. A storage media may 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. Disk and disc, as used herein, include compact disc (CD),
laser disc, optical disc, digital versatile disc (DVD), floppy
disk, and Blu-ray.RTM. disc where disks usually reproduce data
magnetically, while discs reproduce data optically with lasers.
[0084] Thus, certain aspects may comprise a computer program
product for performing the operations presented herein. For
example, such a computer program product may comprise a computer
readable medium having instructions stored (and/or encoded)
thereon, the instructions being executable by one or more
processors to perform the operations described herein. For certain
aspects, the computer program product may include packaging
material.
[0085] Software or instructions may also be transmitted over a
transmission 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 transmission
medium.
[0086] Further, it should be appreciated that modules and/or other
appropriate means for performing the methods and techniques
described herein can be downloaded and/or otherwise obtained by a
user terminal and/or base station as applicable. For example, such
a device can be coupled to a server to facilitate the transfer of
means for performing the methods described herein. Alternatively,
various methods described herein can be provided via storage means
(e.g., RAM, ROM, a physical storage medium such as a compact disc
(CD) or floppy disk, etc.), such that a user terminal and/or base
station can obtain the various methods upon coupling or providing
the storage means to the device. Moreover, any other suitable
technique for providing the methods and techniques described herein
to a device can be utilized.
[0087] It is to be understood that the claims are not limited to
the precise configuration and components illustrated above. Various
modifications, changes and variations may be made in the
arrangement, operation and details of the methods and apparatus
described above without departing from the scope of the claims.
[0088] While the foregoing is directed to embodiments of the
present disclosure, other and further embodiments of the disclosure
may be devised without departing from the basic scope thereof, and
the scope thereof is determined by the claims that follow.
* * * * *