RoHC OPTIMIZATIONS FOR BURST LOSSES

Patent metadata

Field	Value
Publication number	US-2016241685-A1
Application number	US-201414379311-A
Country	US
Kind code	A1
Filing date	Aug 15, 2014
Priority date	Aug 15, 2014
Publication date	Aug 18, 2016
Grant date	—

Abstract

Systems and methods are disclosed for optimizing Robust Header Compression (RoHC) to protect against context desynchronization resulting from a burst of lost packets. In one embodiment, a method of operation of a radio node to adapt a RoHC compressor of a radio node based on a transmit channel quality metric is provided. In another embodiment, systems and methods relating to improved RoHC SN decoding are disclosed. In one embodiment, a method of operation of a radio node includes determining a size of a Packet Data Convergence Protocol (PDCP) Sequence Number (SN) gap for a radio link between the radio node and a second radio node, and performing RoHC SN decoding based on the size of the PDCP SN gap.

First claim

1 . A method of operation of a radio node, comprising:
computing a value for a transmit channel quality metric based on channel quality information for a transmit channel between the radio node and a second radio node; and adapting a Robust Header Compression, RoHC, compressor for a link between the radio node and the second radio node based on the value for the transmit channel quality metric.

2 . The method of claim 1 wherein adapting the RoHC compressor comprises computing a number of least significant bits of a RoHC Sequence Number, SN, to be included in compressed RoHC packets generated by the RoHC compressor based on the value for the transmit channel quality metric.

3 . The method of claim 2 wherein adapting the RoHC compressor further comprises selecting a RoHC packet type for compressed RoHC packets generated by the RoHC compressor based on the number of least significant bits of the RoHC SN to be included in the compressed RoHC packets computed based on the value for the transmit channel quality metric.

4 . The method of claim 1 wherein adapting the RoHC compressor comprises selecting a RoHC packet type for compressed RoHC packets generated by the RoHC compressor based on the value for the transmit channel quality metric.

5 . The method of claim 1 wherein the transmit channel quality metric is indicative of a likelihood that a next transmitted compressed RoHC packet will not be received successfully by a RoHC decompressor of the second radio node.

6 . The method of claim 5 wherein adapting the RoHC compressor comprises:
receiving a new packet for RoHC compression with a value, v, for a RoHC Sequence Number, SN, used by the RoHC compressor;
determining whether the likelihood that the next transmitted compressed RoHC packet will not be received successfully by the RoHC decompressor of the second radio node is greater than a threshold;
incrementing a counter of a number of compressed RoHC packets transmitted consecutively that have been determined to have likely been lost if the likelihood that the next transmitted compressed RoHC packet will not be received successfully by the RoHC decompressor of the second radio node is greater than the threshold;
determining whether the counter of the number of compressed RoHC packets transmitted consecutively that have been determined to have likely been lost is greater than or equal to a lost packet threshold;
if the counter of the number of compressed RoHC packets transmitted consecutively that have been determined to have likely been lost is determined to be greater than or equal to the lost packet threshold, determining a new value for k_c based on a value, v_ref_g, of the RoHC SN for a last compressed RoHC packet determined to have likely been successfully decoded by the RoHC decompressor of the second radio node and the value, v, for the RoHC SN for the new packet for RoHC compression, where k_c is a number of least significant bits of the RoHC SN to be included in compressed RoHC packets;
selecting a RoHC packet type for compressed RoHC packets generated by the RoHC compressor of the radio node based on the new value for k_c; and
processing the new packet to generate a new compressed RoHC packet of the selected RoHC packet type for transmission to the second radio node.

7 . The method of claim 6 wherein adapting the RoHC compressor further comprises:
if the counter of the number of compressed RoHC packets transmitted consecutively that have been determined to have likely been lost is determined to not be greater than or equal to 2 k _ c for the current value of k_c, determining the new value for k_c based on a value, v_ref_c, of the RoHC SN for a last compressed RoHC packet and the value, v, for the RoHC SN for the new packet for RoHC compression.

8 . The method of claim 6 wherein the threshold is 2 k _ c for the current value of k_c used by the RoHC compressor.

9 . The method of claim 6 wherein the counter of the number of compressed RoHC packets transmitted consecutively that have been determined to have likely been lost is indicative of a burst of packets likely to have been lost, and selecting the RoHC packet type comprises:
selecting the RoHC packet type further based on a pattern change detection between a last successfully compressed RoHC packet before the burst of packets likely to have been lost and the new packet.

10 . The method of claim 1 wherein computing the value for the transmit channel quality metric comprises computing the value for the transmit channel quality metric based on a current value of the channel quality information for the transmit channel and one or more previous values of the channel quality information for the transmit channel.

11 . The method of claim 10 wherein the transmit channel quality metric is a number of complete Hybrid Automatic Repeat Request, HARQ, failures compared to HARQ successes or complete HARQ attempts, and computing the value for the transmit channel quality metric based on the current value of the channel quality information for the transmit channel and the one or more previous values of the channel quality information for the transmit channel comprises computing the value for the transmit channel quality metric as an exponentially weighted moving average of the number of complete HARQ failures compared to HARQ successes or complete HARQ attempts.

12 . The method of claim 1 wherein computing the value for the transmit channel quality metric comprises:
obtaining a new value for the channel quality information for the transmit channel;
computing the value for the transmit channel quality metric based on the new value for the channel quality information and the one or more previous values for the channel quality information;
making the value for the transmit channel quality metric available to the RoHC compressor; and
repeating the steps of obtaining a new value for the channel quality information for the transmit channel, computing the value for the transmit channel quality metric, and making the value for the transmit channel quality metric available to the RoHC compressor.

13 . A radio node comprising:
a processor; and memory containing software executable by the processor whereby the radio node is operative to:
compute a value for a transmit channel quality metric based on channel quality information for a transmit channel between the radio node and a second radio node; and
adapting a Robust Header Compression, RoHC, compressor for a link between the radio node and the second radio node based on the value for the transmit channel quality metric.

14 - 19 . (canceled)

20 . A method of operation of a radio node, comprising:
determining a size of a Packet Data Convergence Protocol, PDCP, Sequence Number, SN, gap for a radio link between the radio node and a second radio node; and performing Robust Header Compression, RoHC, SN decoding based on the size of the PDCP SN gap.

21 . The method of claim 20 wherein performing RoHC SN decoding based on the PDCP SN gap comprises:
determining whether the size of the PDCP SN gap is greater than a threshold gap size; and
performing RoHC SN decoding for a received RoHC compressed PDCP Protocol Data Unit, PDU, using the size of the PDCP SN gap if the size of the PDCP SN gap is greater than the threshold gap size.

22 . The method of claim 21 wherein performing RoHC SN decoding based on the size of the PDCP SN gap further comprises determining the RoHC SN for the received RoHC compressed PDCP PDU without using the size of the PDCP SN gap if the size of the PDCP SN gap is greater

Assignees

• Ericsson Telefon Ab L M

Inventors

• Shah Samir
• Fong John
• Turcanu Adrian

Classifications

• H04L69/40 Primary

  for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection (management of faults, events, alarms or notifications in data switching networks H04L41/06) · CPC title

• H04W80/04

  Network layer protocols, e.g. mobile IP [Internet Protocol] · CPC title

• H04L47/34

  ensuring sequence integrity, e.g. using sequence numbers · CPC title

• H04L69/322

  Intralayer communication protocols among peer entities or protocol data unit [PDU] definitions · CPC title

• H04L1/1812

  Hybrid protocols; Hybrid automatic repeat request [HARQ] · CPC title