Near-Optimal One-Sided Scheduling for Coded Segmented Network Coding

Abstract

As a variation of random linear network coding, segmented network coding (SNC) has attracted great interest in data dissemination over lossy networks due to its low computational cost. In order to guarantee the success of decoding, SNC can adopt a feedbackless FEC (forward error correction) approach by applying a linear block code to the input packets before segmentation at the source node. In particular, if the empirical rank distribution of transfer matrices of segments is known in advance, several classes of coded SNC can achieve close-to-optimal decoding performance. However, the empirical rank distribution in the absence of feedback has been little investigated yet, making the whole performance of the FEC approach unknown. To close this gap, in this paper, we present the first comprehensive study on the transmission scheduling issue for the FEC approach, aiming at optimizing the rank distribution of transfer matrices with little control overhead. We propose an efficient adaptive scheduling framework for coded SNC in lossy unicast networks. This framework is one-sided (i.e., each network node forwards the segments adaptively only according to its own state) and scalable (i.e., its buffer cost will not keep on growing when the number of input packets goes to infinity). The performance of the framework is further optimized based on a linear programming approach. Extensive numerical results show that our framework performs near-optimally with respect to the empirical rank distribution.Index Terms-Random linear network coding, segmented network coding, forward error correction, scheduling strategy. ! 0018-9340 (c)

Expander chunked codes

“…Various chunked code-based transmission schemes have been designed and implemented recently [18,22,32], which are consistent with our transfer matrix model.…”

“…For convenience, we refer to a packet with chunk ID j as a j packet. Now, we describe a chunk transmission model through a network employing linear network coding, which is consistent with the recent design and implementation of chunked code-based network protocols [18,22,32]. Consider the jth chunk of packets b j 1 , b j 2 , .…”

“…To further see the real-world potential of EC codes, we then evaluate the performance for a near-optimal chunk transmission scheme over line-topology (line) networks [18]. As most practical routing schemes are singlepath based, line networks have attracted a lot of interest [19][20][21].…”

“…As most practical routing schemes are singlepath based, line networks have attracted a lot of interest [19][20][21]. Also, the chunked code scheme for line networks can be extended to general network scenarios, including general unicast networks [14,18], two-way relay networks [22], and wireless broadcast networks [23]. For a wide range of the packet loss rates, with proper optimization of the transmission scheme, EC codes achieve rates very close to those of the coded chunked codes and about 91 % ∼ 97 % of the theoretical upper bounds.…”

“…Note that in (1), we only need to combine the j packets with linearly independent coefficient vectors. For the scheduling issue, i.e., how to choose a chunk B j by each intermediate node for each transmission, please refer to some recent proposed network protocols [18,22,32]. At the destination node, let T j be the matrix formed by the coefficient vectors of all the j packets received, and let Y j be the matrix formed by the payloads of all the j packets received.…”