INCREMENTAL REDUNDANCY RELAYS FOR BROADCAST TRANSMISSION

• US 20100110966A1
• Filed: 10/31/2008
• Published: 05/06/2010
• Est. Priority Date: 10/31/2008
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Palanki, Ravi, Agrawal, Avneesh
• Granted Patent: US 8,638,710 B2
• Time in Patent Office: Days
• US Class Current: 370/315
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04L 1/1812 Hybrid protocols; Hybrid automatic repeat request [HARQ]
• CPC Class Codes: H04L 2001/0097 Relays

Abstract

Techniques for relaying a broadcast transmission in a wireless network are described. In one design, a relay may receive at least one transmission of a packet from a transmitter (e.g., a broadcast station) and may process the at least one transmission to decode the packet. The relay may generate at least one remaining transmission of the packet after correctly decoding the packet. The transmitter may broadcast multiple transmissions of the packet to receivers. The at least one transmission may be at least one of the multiple transmissions, and the at least one remaining transmission may be remaining ones of the multiple transmissions. The relay may send the at least one remaining transmission of the packet at the same time and on the same resources used by the transmitter. The multiple transmissions may be HARQ transmissions containing different redundancy information for the packet.

Claims

1. A method for wireless communication, comprising:

receiving at least one transmission of a packet from a transmitter at a relay, the at least one transmission being at least one of multiple transmissions of the packet broadcast by the transmitter to receivers;

processing the at least one transmission of the packet to decode the packet;

generating at least one remaining transmission of the packet after correctly decoding the packet, the at least one remaining transmission being remaining ones of the multiple transmissions of the packet; and

sending the at least one remaining transmission of the packet from the relay.

2. The method of claim 1, wherein the transmitter broadcasts a fixed number of transmissions of the packet regardless of decoding results by the receivers.

3. The method of claim 1, wherein the multiple transmissions of the packet are hybrid automatic repeat request (HARQ) transmissions comprising different redundancy information for the packet.

4. The method of claim 1, wherein the sending the at least one remaining transmission of the packet comprises sending each remaining transmission of the packet from the relay at same time that the transmitter is sending the remaining transmission.

5. The method of claim 1, further comprising:

determining resources used by the transmitter to send the at least one remaining transmission of the packet, and wherein the at least one remaining transmission of the packet is sent from the relay on the resources used by the transmitter.

6. The method of claim 1, further comprising:

determining a packet format used by the transmitter for the packet, wherein the at least one transmission of the packet is processed in accordance with the packet format to decode the packet, and wherein the at least one remaining transmission of the packet is generated in accordance with the packet format.

7. The method of claim 1, further comprising:

receiving at least one transmission of a message from the transmitter at the relay, the message comprising information used to receive the packet;

processing the at least one transmission of the message to decode the message;

generating at least one remaining transmission of the message after correctly decoding the message; and

sending the at least one remaining transmission of the message from the relay.

8. The method of claim 7, wherein the message comprises system information.

9. The method of claim 7, wherein the message comprises an assignment for the packet.

10. The method of claim 1, wherein the generating the at least one remaining transmission of the packet comprises, for each remaining transmission,

mapping data symbols for the remaining transmission to resources used by the transmitter for data,

mapping pilot symbols to resources used by the transmitter for pilot, and

generating the remaining transmission based on the mapped data symbols and the mapped pilot symbols.

11. The method of claim 1, further comprising:

adjusting transmit timing of the relay such that transmissions from the relay are received within a predetermined time window of transmissions from the transmitter at a receiver, and wherein the at least one remaining transmission of the packet is sent from the relay in accordance with the transmit timing of the relay.

12. The method of claim 1, further comprising:

determining a transmit power level for the relay such that received power of transmissions from the relay is within a predetermined range at a receiver, and wherein the at least one remaining transmission of the packet is sent from the relay at the determined transmit power level.

13. The method of claim 1, further comprising:

sending no transmissions of the packet from the relay if the packet has not been decoded correctly.

14. The method of claim 1, further comprising:

until the packet is decoded correctly

reconditioning a signal received from the transmitter, and

transmitting the reconditioned signal from the relay.

15. The method of claim 1, wherein the transmitter is a broadcast station in a broadcast network, and wherein the packet is for a broadcast stream sent by the broadcast station to the receivers.

16. An apparatus for wireless communication, comprising:

at least one processor configured to receive at least one transmission of a packet from a transmitter at a relay, to process the at least one transmission of the packet to decode the packet, to generate at least one remaining transmission of the packet after correctly decoding the packet, and to send the at least one remaining transmission of the packet from the relay, the at least one transmission being at least one of multiple transmissions of the packet broadcast by the transmitter to receivers, and the at least one remaining transmission being remaining ones of the multiple transmissions of the packet.

17. The apparatus of claim 16, wherein the at least one processor is configured to determine resources used by the transmitter to send the at least one remaining transmission of the packet, and to send the at least one remaining transmission of the packet on the resources used by the transmitter.

18. The apparatus of claim 16, wherein the at least one processor is configured to determine a packet format used by the transmitter for the packet, to process the at least one transmission of the packet in accordance with the packet format to decode the packet, and to generate the at least one remaining transmission of the packet in accordance with the packet format.

19. The apparatus of claim 16, wherein for each remaining transmission of the packet the at least one processor is configured to map data symbols for the remaining transmission to resources used by the transmitter for data, to map pilot symbols to resources used by the transmitter for pilot, and to generate the remaining transmission based on the mapped data symbols and the mapped pilot symbols.

20. An apparatus for wireless communication, comprising:

means for receiving at least one transmission of a packet from a transmitter at a relay, the at least one transmission being at least one of multiple transmissions of the packet broadcast by the transmitter to receivers;

means for processing the at least one transmission of the packet to decode the packet;

means for generating at least one remaining transmission of the packet after correctly decoding the packet, the at least one remaining transmission being remaining ones of the multiple transmissions of the packet; and

means for sending the at least one remaining transmission of the packet from the relay.

21. The apparatus of claim 20, further comprising:

means for determining resources used by the transmitter to send the at least one remaining transmission of the packet, and wherein the at least one remaining transmission of the packet is sent from the relay on the resources used by the transmitter.

22. The apparatus of claim 20, further comprising:

means for determining a packet format used by the transmitter for the packet,

wherein the at least one transmission of the packet is processed in accordance with the packet format to decode the packet, and

wherein the at least one remaining transmission of the packet is generated in accordance with the packet format.

23. The apparatus of claim 20, wherein the means for generating at least one remaining transmission of the packet comprises, for each remaining transmission,

means for mapping data symbols for the remaining transmission to resources used by the transmitter for data,

means for mapping pilot symbols to resources used by the transmitter for pilot, and

means for generating the remaining transmission based on the mapped data symbols and the mapped pilot symbols.

24. A computer program product, comprising:

a computer-readable medium comprising;

code for causing at least one computer to receive at least one transmission of a packet from a transmitter at a relay, the at least one transmission being at least one of multiple transmissions of the packet broadcast by the transmitter to receivers,

code for causing at least one computer to process the at least one transmission of the packet to decode the packet,

code for causing the at least one computer to generate at least one remaining transmission of the packet after correctly decoding the packet, the at least one remaining transmission being remaining ones of the multiple transmissions of the packet, and

code for causing the at least one computer to send the at least one remaining transmission of the packet from the relay.

25. A method for wireless communication, comprising:

receiving at least one transmission of a packet from a transmitter, the at least one transmission being at least one of multiple transmissions of the packet broadcast by the transmitter to receivers;

receiving at least one additional transmission of the packet from the transmitter and a relay, the at least one additional transmission being at least one remaining one of the multiple transmissions of the packet; and

processing the at least one transmission and the at least one additional transmission of the packet to decode the packet.

26. The method of claim 25, wherein the transmitter broadcasts a fixed number of transmissions of the packet regardless of decoding results by the receivers, and wherein the multiple transmissions of the packet are hybrid automatic repeat request (HARQ) transmissions comprising different redundancy information for the packet.

27. The method of claim 25, further comprising:

receiving at least one transmission of a message from the transmitter, the message comprising information used to receive the packet;

receiving at least one additional transmission of the message from the transmitter and the relay; and

processing the at least one transmission and the at least one additional transmission of the message to decode the message.

28. The method of claim 27, further comprising:

obtaining system information from the message, and wherein the at least one transmission and the at least one additional transmission of the packet are received in accordance with the system information.

29. The method of claim 27, further comprising:

obtaining an assignment from the message, and wherein the at least one transmission and the at least one additional transmission of the packet are received and processed in accordance with the assignment.

30. The method of claim 25, wherein the processing the at least one transmission and the at least one additional transmission of the packet comprises, for each of the at least one transmission,

deriving a first channel estimate for the transmitter based on pilot symbols in the transmission, and

performing detection for the transmission based on the first channel estimate.

31. The method of claim 30, wherein the processing the at least one transmission and the at least one additional transmission of the packet further comprises, for each of the at least one additional transmission,

deriving a second channel estimate for both the transmitter and the relay based on pilot symbols in the additional transmission, and

performing detection for the additional transmission based on the second channel estimate.

32. The method of claim 25, further comprising:

determining timing adjustment for the relay such that transmissions from the relay are received within a predetermined time window of transmissions from the transmitter at a receiver; and

sending the timing adjustment to the relay.

33. The method of claim 25, further comprising:

operating in an awake state during the at least one transmission and the at least one additional transmission of the packet; and

operating in a sleep state for remaining ones of the multiple transmissions of the packet.

34. An apparatus for wireless communication, comprising:

at least one processor configured to receive at least one transmission of a packet from a transmitter, to receive at least one additional transmission of the packet from the transmitter and a relay, and to process the at least one transmission and the at least one additional transmission of the packet to decode the packet, the at least one transmission being at least one of multiple transmissions of the packet broadcast by the transmitter to receivers, and the at least one additional transmission being at least one remaining one of the multiple transmissions of the packet.

35. The apparatus of claim 34, wherein the at least one processor is configured to derive a first channel estimate for the transmitter for each transmission of the packet based on pilot symbols in the transmission, to perform detection for each transmission of the packet based on the first channel estimate for the transmission, to derive a second channel estimate for both the transmitter and the relay for each additional transmission of the packet based on pilot symbols in the additional transmission, and to perform detection for each additional transmission of the packet based on the second channel estimate for the additional transmission.

36. The apparatus of claim 34, wherein the at least one processor is configured to determine timing adjustment for the relay such that transmissions from the relay are received within a predetermined time window of transmissions from the transmitter at a receiver, and to send the timing adjustment to the relay.

37. A method for wireless communication, comprising:

receiving at least one transmission of a packet from a transmitter at a relay;

processing the at least one transmission of the packet to decode the packet;

generating at least one additional transmission of the packet after correctly decoding the packet;

adjusting transmit timing of the relay such that transmissions from the relay are received within a predetermined time window of transmissions from the transmitter at a receiver; and

sending the at least one additional transmission of the packet in accordance with the transmit timing from the relay to the receiver.

38. The method of claim 37, wherein the adjusting transmit timing of the relay comprises

receiving timing adjustment from the receiver, and

adjusting the transmit timing of the relay in accordance with the timing adjustment.

39. The method of claim 37, wherein the adjusting transmit timing of the relay comprises

determining receive timing of the relay based on the at least one transmission of the packet from the transmitter, and

setting the transmit timing of the relay based on the receive timing of the relay.

40. An apparatus for wireless communication, comprising:

at least one processor configured to receive at least one transmission of a packet from a transmitter at a relay, to process the at least one transmission of the packet to decode the packet, to generate at least one additional transmission of the packet after correctly decoding the packet, to adjust transmit timing of the relay such that transmissions from the relay are received within a predetermined time window of transmissions from the transmitter at a receiver, and to send the at least one additional transmission of the packet in accordance with the transmit timing from the relay to the receiver.

41. The apparatus of claim 40, wherein the at least one processor is configured to receive timing adjustment from the receiver and to adjust the transmit timing of the relay in accordance with the timing adjustment.

42. The apparatus of claim 40, wherein the at least one processor is configured to determine receive timing of the relay based on the at least one transmission of the packet from the transmitter, and to set the transmit timing of the relay based on the receive timing of the relay.