Two-Phase Cooperative Broadcasting Based on Batched Network Code

• Published in: IEEE transactions on communications Vol. 64; no. 2; pp. 706 - 714
• Main Authors: Xu, Xiaoli, Praveen Kumar, Meenakshi Sundaram Gandhi, Guan, Yong Liang, Joo Chong, Peter Han
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.02.2016; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Bats; BATS code; Broadcasting; channel rank distribution; Channels; cooperative broadcasting; Encoders; Links; Maintenance engineering; Multimedia communication; Networks; P2P communications; Peer-to-peer computing; Protocols; Reliability; scheduling; User requirements; Wireless communication; scheduling; P2P communications; cooperative broadcasting; channel rank distribution; BATS code
• ISSN: 0090-6778; 1558-0857
• DOI: 10.1109/TCOMM.2015.2512584

In this paper, we consider the wireless broadcasting scenario with a source node sending some common information to a group of closely located users, where each link is subject to certain packet erasures. To ensure reliable information reception by all users, the conventional approach generally requires repeated transmission by the source until all the users are able to decode the information, which is inefficient in many practical scenarios. In this paper, by exploiting the close proximity among the users, we propose a novel two-phase wireless broadcasting protocol with user cooperations based on an efficient batched network code, known as batched sparse (BATS) code. In the first phase, the information packets are encoded into batches with BATS encoder and sequentially broadcasted by the source node until certain terminating criterion is met. In the second phase, the users cooperate with each other by exchanging the network-coded information via peer-to-peer (P2P) communications based on their respective received packets. A fully distributed and light-weight scheduling algorithm is proposed to improve the efficiency of the P2P communication in the second phase. The performance of the proposed two-phase protocol is analyzed and the channel rank distribution at the instance of decoding is derived, based on which the optimal BATS code is designed. Simulation results show that the proposed protocol outperforms most existing cooperative packet exchange schemes, especially when the inter-user links are not reliable. Lastly, the performance of the proposed scheme is further verified via testbed experiments.