batchedsparse (BATS) code is a promising technology for reliable data transmission in error-prone environments. A BATS code consists of an outer code and an inner code. It has been shown that a well-designed inner co...
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batchedsparse (BATS) code is a promising technology for reliable data transmission in error-prone environments. A BATS code consists of an outer code and an inner code. It has been shown that a well-designed inner code is critical to the performance of BATS. Though great efforts have been made in the design of inner codes, the impact of scheduling (that determines when inner codes take place at nodes in the path) on inner codes is still unclear. In this paper, we study the joint design of inner code and scheduling in multihop wireless networks. We first introduce a new network utility from which to associate inner codes with scheduling, and formulate the coding constraint and the scheduling constraint using independent sets of a graph. With the utility, the joint design problem is then transformed to a network utility maximization problem under the constraints. We next exploit the property of the proposed optimization problem and reveal the relation between the expected batch transfer matrix rank and maximal independent sets. In the light of their relationship, we propose joint coding and scheduling rules and show that a periodic scheduling can be used to achieve provable performance guarantees. However, under most realistic coding settings, the proposed coding and scheduling problem is NP-hard. In order to meet the practical needs of the implementation, we develop greedy algorithms that attempt to iteratively improve the current best solution. Numerical results show that our algorithms enables us to approach the utilization of multi-hop wireless networks with a relatively low end-to-end delay.
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...
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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 batchedsparse (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.
batchedsparse (BATS) codes are proposed for transmitting a collection of packets through communication networks employing linear network coding. BATS codes generalize fountain codes and preserve the properties such a...
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ISBN:
(纸本)9781457705953
batchedsparse (BATS) codes are proposed for transmitting a collection of packets through communication networks employing linear network coding. BATS codes generalize fountain codes and preserve the properties such as ratelessness and low encoding/decoding complexity. Moreover, the buffer size and the computation capability of the intermediate network nodes required to apply BATS codes are independent of the number of packets for transmission. It is verified theoretically for certain cases and demonstrated numerically for the general cases that BATS codes achieve rates very close to the capacity of linear operator channels.
Aiming at the popular wireless multi-hop network, this paper proposes a concise and practical endurance network coding scheme which can nearly reach the capacity of wireless multi-hop network. In this scheme, the sour...
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ISBN:
(纸本)9781665421607;9781665421591
Aiming at the popular wireless multi-hop network, this paper proposes a concise and practical endurance network coding scheme which can nearly reach the capacity of wireless multi-hop network. In this scheme, the source node encodes a group of packets to be sent, the intermediate node expands and forwards the received coded packets by using a causal systematic upper triangular recoding matrix, and the receiver node judges a whole group of packets received and sends feedback to the sender according to whether it is decodable. These operations have three advantages: 1) Increase the probability of first transmission and reducing the number of retransmission;2) The flow transmission and expansion on intermediate nodes ensure low latency and improve reliability respectively;3) Feedback can further increase reliability and throughput. Through analysis and simulation results, we prove that the proposed scheme can achieve a better compromise between throughput and packet delay. Furthermore, the transmission scheme can be compatible with a variety of existing coding methods to ensure the above performance of throughput and delay while maintaining their respective advantages.
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