Efficient packet combining based on packet-level coding

Abstract

A new packet-combining (PC) scheme based on packet-level coding is proposed. Through feedback, the receiver controls the transmitting node to encode (XOR) source packets. Efficient methods to combat even-errors among erroneous packets are investigated. Also proposed is a reduced-complexity decoder. Numerical results show that the proposed scheme can significantly outperform the ARQ scheme or PC without coding.Introduction: Packet-level coding (e.g. network coding [1, 2]) has recently attracted substantial research interest for the applications of packet-level error control [3,4], though it was originally proposed for error-free networks. The schemes in [3,4] are generally more efficient than ARQ, which simply retransmits erroneous packets. For ARQ or network-coding-based schemes [3, 4], a packet is dropped, if any bit error is detected, e.g. by CRC. However, if the channel is in a good condition, the packets may only have a small number of erroneous bits. Thus, dropping the whole packet is inefficient. Based on this observation, [5], [6] propose packet combining (PC) to improve transmission efficiency. For PC, a packet is retransmitted if any error is detected, similar to ARQ.Yet, if the retransmitted packet also has errors, two erroneous packets are used to recover the source information jointly, rather than are dropped. Briefly, two erroneous packets are compared to find the locations of erroneous bits. With the locations, the receiver uses a brute-forced approach to search for correct source information. Hence, PC is an extension or modification of ARQ. Clearly, PC is invoked only when consecutive retransmitted packets have errors, and also one retransmitted packet can only be used for recovering one information packet. This limits the efficiency and application of PC.Based on the observation, we propose an error correction scheme combining packet-level coding and PC. Different from previous PC, a retransmitted packet is constructed for multiple erroneous information packets through coding. As we show, appropriate coding can substantially increase the transmission efficiency.

Packet combining based on cross-packet coding

“…Different from previous PC techniques, a retransmitted packet is constructed for multiple erroneous source packets through coding. As shown in [16], this substantially increases the transmission efficiency.…”

“…Finally, by replacing (24) and (25) into (16) and 15, we obtain the relation between rate R and the number of systematic packets k given bit error probability of BSC channel P b . Then based on the equation, we can maximize the rate by optimizing the value of k.…”

“…Based on the observation, we have proposed an error correction scheme for combining cross-packet coding and PC in [16]. Different from previous PC techniques, a retransmitted packet is constructed for multiple erroneous source packets through coding.…”

A comparative study of packet combining based error recovery schemes for wireless networks

“…The literature has argued that even if all the received copies of packets are erroneous, it may be possible to combine these copies to recover the correct packet (Miu et al, 2005). Recent studies enlightened by Sindhu (1977) have proposed numerous mechanisms to retrieve original packets for a variety of wireless networks (Miu et al, 2005;Bhunia, 2005;Chakraborty et al, 1998;Liang and Chakraborty, 2004;Dubois-Ferrìère et al, 2005;Zhou et al, 2011;Ur-Rehman et al, 2011;Lin et al, 2011;Bhunia, 2012). The main idea behind these schemes is packet combining.…”

A Novel Decoding Method for Rateless Codes Basing on Packet Combing

“…The basic idea of PC is to find the possible positions of the erroneous bits by comparing the packets in an equation and brute-forcedly flip the possible erroneous positions. The authors in [14] combine the network coding with the PC technique to improve the performance. Motivated by these research backgrounds, in this paper, we will study two hybrid schemes of PC with rateless codes.…”