Multiplexing schemes for OFDMA

• US 9,071,403 B2
• Filed: 09/14/2012
• Issued: 06/30/2015
• Est. Priority Date: 10/21/2005
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Novak, Robert, Zhang, Hang, Vrzic, Sophie, Fong, Mo-Han, Au, Kelvin Kar-Kin, Ma, Jianglel, Zhu, Peiying, Tong, Wen
• Primary Examiner(s): PASIA, REDENTOR M
• Application Number:
  US13/616,433
• Publication Number:
  US 20130003526A1
• Time in Patent Office: 1,019 Days
• Field of Search: 370/389, 370/394, 370/474, 714748-750
• US Class Current: 1/1
• CPC Class Codes: H04L 1/0013 Rate matching, e.g. puncturing or repetition of code symbols
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/0067 Rate matching H04L1/0013 and H04L1/08 take precedence
• CPC Class Codes: H04L 1/14 in which the signals are sent back to the transmitter to be checked ; echo systems
• CPC Class Codes: H04L 1/1614 using bitmaps
• CPC Class Codes: H04L 1/1867 Arrangements specially adapted for the transmitter end
• CPC Class Codes: H04L 2001/0093 Point-to-multipoint
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0037 Inter-user or inter-terminal allocation
• CPC Class Codes: H04L 5/0042 intra-user or intra-terminal allocation
• CPC Class Codes: H04L 5/0046 Determination of how many bits are transmitted on different sub-channels
• CPC Class Codes: H04L 5/0064 Rate requirement of the data, e.g. scalable bandwidth, data priority
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/70 Media network packetisation
• CPC Class Codes: H04L 65/80 Responding to QoS

Abstract

Methods and systems are provided for allocating resources including VoIP (voice over Internet Protocol) and Non-VoIP resources. In some embodiments, multiplexing schemes are provided for use with OFDMA (orthogonal frequency division multiplexing access) systems, for example for use in transmitting VoIP traffic. In some embodiments, various HARQ (Hybrid Automatic request) techniques are provided for use with OFDMA systems. In various embodiments, there are provided methods and systems for dealing with issues such as Handling non-full rate vocoder frames, VoIP packet jitter handling, VoIP capacity increasing schemes, persistent and non-persistent assignment of resources in OFDMA systems.

Claims

1. A method comprising:

allowing, by a wireless terminal, a maximum number of HARQ transmissions for a first packet, wherein the maximum number is not an integer multiple of a number of interlace offsets;

recovering, by the wireless terminal, from possible feedback errors when a negative acknowledgement (NAK) is mistakenly received by a base station for a positive acknowledgement (ACK) or when an ACK is mistakenly received by a base station for a NAK; and

determining, by the wireless terminal, that a second packet is being transmitted instead of the first packet based on the wireless terminal receiving more retransmissions for the first packet than is allowed.

2. The method of claim 1, wherein the wireless terminal recovering from possible feedback errors comprises:

when more HARQ transmissions are received than are allowed for the first packet, the wireless terminal emptying a buffer storing previously received HARQ transmissions for the first packet and using the most recently received HARQ transmission as a HARQ transmission for the second packet.

3. The method of claim 1, wherein the maximum number of allowed HARQ transmissions for the first packet is five and the number of interlace offsets is three.

4. The method of claim 1, wherein the maximum number of allowed HARQ transmissions for the first packet is seven.

5. The method of claim 1, wherein said recovering from possible feedback errors comprises utilizing a plurality of packet buffers, wherein a first packet buffer is used for the first packet and a second packet buffer is used for the second packet.

6. The method of claim 5, wherein an incoming transmission is stored in both the first packet buffer and the second packet buffer, wherein a packet associated with the incoming transmission is unknown.

7. A wireless station, comprising:

one or more antennas for performing wireless communication;

processing hardware coupled to the one or more antennas, wherein the processing hardware is configured to;

allow a maximum number of HARQ transmissions for a first packet, wherein the maximum number is not an integer multiple of a number of interlace offsets;

recover from possible feedback errors when a negative acknowledgement (NAK) is mistakenly received by a base station for a positive acknowledgement (ACK) or when an ACK is mistakenly received by a base station for a NAK; and

determine that a second packet is being transmitted instead of the first packet based on the wireless station receiving more retransmissions for the first packet than is allowed.

8. The wireless station of claim 7, wherein recovering from possible feedback errors comprises:

when more HARQ transmissions are received than are allowed for the first packet, emptying a buffer storing previously received HARQ transmissions for the first packet and using the most recently received HARQ transmission as a HARQ transmission for the second packet.

9. The wireless station of claim 7, wherein the maximum number of allowed HARQ transmissions for the first packet is five and the number of interlace offsets is three.

10. The wireless station of claim 7, wherein the maximum number of allowed HARQ transmissions for the first packet is seven.

11. The wireless station of claim 7, wherein said recovering from possible feedback errors comprises utilizing a plurality of packet buffers, wherein a first packet buffer is used for the first packet and a second packet buffer is used for the second packet.

12. The wireless station of claim 11, wherein an incoming transmission is stored in both the first packet buffer and the second packet buffer, wherein a packet associated with the incoming transmission is unknown.

13. A method comprising:

failing, by a wireless station, to successfully receive and decode a first packet a plurality of times;

sending, by the wireless station, a corresponding number of NAKs in response to failing to successfully receive and decode the first packet, wherein a last NAK of the number of NAKs is mistakenly received as an ACK;

failing, by the wireless station, to successfully receive and decode the first packet after the last NAK is mistakenly received as an ACK, wherein a second packet was transmitted instead of the first packet based on the last NAK being mistakenly received as an ACK;

sending, by the wireless station, another NAK in response to failing to successfully receive and decode the first packet after the last NAK is mistakenly received as an ACK;

determining, by the wireless station, that a second packet is being transmitted instead of the first packet based on the wireless station receiving more retransmissions for the first packet than is allowed; and

attempting, by the wireless station, to recover the second packet based on said determining that the second packet is being transmitted instead of the first packet.

14. The method of claim 13, wherein the number of allowed transmissions is 5.

15. The method of claim 13, wherein said attempting to recover the second packet comprises the wireless station emptying a buffer storing previously received transmissions for the undecoded first packet and using the most recently received transmission as a transmission for the second packet.

16. The method of claim 13, further comprising:

storing transmissions for the first packet in a first packet buffer; and

storing transmissions for the second packet in a second packet buffer.

17. The method of claim 16, further comprising:

storing at least one transmission in both the first and the second buffer; and

attempting to decode the first and second packets using the first and second buffers, including the at least one transmission stored in both the first and second buffer.

18. A wireless station, comprising:

one or more antennas for performing wireless communication;

processing hardware coupled to the one or more antennas, wherein the processing hardware is configured to;

fail to successfully receive and decode a first packet a plurality of times;

transmit a corresponding number of NAKs in response to failing to successfully receive and decode the first packet, wherein a last NAK of the number of NAKs is mistakenly received as an ACK;

fail to successfully receive and decode the first packet after the last NAK is mistakenly received as an ACK, wherein a second packet was transmitted instead of the first packet based on the last NAK being mistakenly received as an ACK;

send another NAK in response to failing to successfully receive and decode the first packet after the last NAK is mistakenly received as an ACK;

determine that a second packet is being transmitted instead of the first packet based on the wireless station receiving more retransmissions for the first packet than is allowed; and

attempt to recover the second packet based on said determining that the second packet is being transmitted instead of the first packet.