V2X Content Distribution Based on Batched Network Coding With Distributed Scheduling

Abstract

Content distribution is an application in intelligent transportation system to assist vehicles in acquiring information such as digital maps and entertainment materials. In this paper, we consider content distribution from a single roadside infrastructure unit to a group of vehicles passing by it. To combat the short connection time and the lossy channel quality, the downloaded contents need to be further shared among vehicles after the initial broadcasting phase. To this end, we propose a joint infrastructure-to-vehicle (I2V) and vehicle-to-vehicle (V2V) communication scheme based on batched sparse (BATS) coding to minimize the traffic overhead and reduce the total transmission delay. In the I2V phase, the roadside unit (RSU) encodes the original large-size file into a number of batches in a rateless manner, each containing a fixed number of coded packets, and sequentially broadcasts them during the I2V connection time. In the V2V phase, vehicles perform the network coded cooperative sharing by re-encoding the received packets. We propose a utility-based distributed algorithm to efficiently schedule the V2V cooperative transmissions, hence reducing the transmission delay. A closed-form expression for the expected rank distribution of the proposed content distribution scheme is derived, which is used to design the optimal BATS code. The performance of the proposed content distribution scheme is evaluated by extensive simulations that consider multi-lane road and realistic vehicular traffic settings, and shown to significantly outperform the existing content distribution protocols.Index Terms-Vehicular networks, joint I2V and V2V communication, content distribution, batched sparse code, channel rank distribution.

Joint BATS Code and Periodic Scheduling in Multihop Wireless Networks

“…In [16], the authors proposed a distributed two-phase cooperative broadcasting protocol, which uses BATS codes in the first phase to help the peerto-peer (P2P) communications. Further, a BATS-based V2X communication scheme was developed, where a vehicle node determines which batch should be forwarded first according to its contribution to the transmission [17]. In [13], BATS was employed to improve the reliability of the uplink transmissions in industrial Internet of Things.…”

“…These features make BATS codes suitable for multihop wireless networks. Afterwards, many works have been concerned with the implementation of BATS codes in a variety of wireless applications, such as wireless sensor networks [10], vehicular networks [17], underwater acoustic networks [12], Internet of Things (IoT) [13], etc..…”

Low Delay Inter-Packet Coding in Vehicular Networks

“…Thorough analysis of state-of-the-art solutions for reliable data transmission in V2V and V2R communication scenarios is presented in [12]. Moreover, the batched sparse code (BATS code) [13] based protocol is suggested.…”

“…A semi-infinite parity-check matrix of the RS-convolutional code is defined by Equations (2) and (12). The encoding procedure can be simplified by rewriting columns of H (m) in Equation (12) in the reverse order. In particular, for R = 3/4 and n = 4, the reordered matrix has the form…”

“…Notice that, if the field extension parameter c > n, then all elements of parity-check matrix in Equation (12) have the Hamming weight 1 and all multiplications in Equation 18are implemented as simple cyclic shifts.…”