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A complexity-reduced fast successive cancellation list decoder for polar codes SCIENCE CHINA Information Sciences 61, 022309 (2018); The lower and upper bounds of the degree distribution of a graded algebra SCIENCE CHINA Mathematics 56, 983 (2013); Low-degree root-MUSIC algorithm for fast DOA estimation based on variable substitution technique SCIENCE CHINA Information Sciences 63, 159206 (2020); Period distribution of generalized B-J codes and constructions of cyclically permutable (CP ) codesAbstract Batched sparse (BATS) codes have been proposed for communication through networks with packet loss. BATS codes include a matrix generalization of fountain codes as the outer code and random linear network coding at the intermediate network nodes as the inner code. BATS codes, however, do not possess a universal degree distribution that achieves an optimal rate for any distribution of the transfer matrix ranks. Therefore, it is important to have a fast degree-distribution optimization approach for finite-length BATS codes. In this paper, we propose the concept of batch release probability (BRP), and demonstrate some characteristics of BRPs from the degree distributions achieving nearly optimal performance. Based on these BRP characteristics, we propose a novel degree-distribution optimization approach that achieves the similar decoding performance with a much shorter optimization time, compared with the previous approach. Moreover, the universality of BRPs observed in this paper can further simplify the degree-distribution optimization of BATS codes.

This paper investigates minimizing mutual interferences in wireless ad hoc networks by means of topology control. Prior work defines interference as a relationship between link and node. This paper attempts to capture the physical situation more realistically by defining interference as a relationship between link and link. We formulate the pair-wise interference condition between two links, and show that the interference conditions for the minimum-transmit-power strategy and the equal-transmit-power strategy are equivalent. Based on the pair-wise definition, we further investigate the "typical" interference relationship between a link and all other links in its surrounding. To characterize the extent of the interference between a link and its surrounding links, we define a new metric called the interference coefficient. We investigate the property of interference coefficient in detail by means of analysis and simulation. Based on the insight obtained, we propose a topology control algorithm -minimum interference algorithm (MIA) -to minimize the overall network interference. Simulation results indicate that the network topologies produced by MIA show good performance in terms of network interference and spanner property compared with known algorithms such as LIFE, Gabriel Graph and k-NEIGH.

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