西安电子科技大学学报（自然科学版）2024，Vol.51Issue(3)：1-8,8.DOI:10.19665/j.issn1001-2400.20230907
叠加导频传输无标识随机接入方案研究
Superimposed pilots transmission for unsourced random access
摘要
Abstract
In unsourced random access,the base station(BS)only needs to recover the messages sent by each active device without identifying the device,which allows a large number of active devices to access the BS at any time without requiring a resource in advance,thereby greatly reducing the signaling overhead and transmission delay,which has attracted the attention of many researchers.Currently,many works are devoted to design random access schemes based on preamble sequences.However,these schemes have poor robustness when the number of active devices changes,and cannot make full use of channel bandwidth,resulting in poor performance when the number of active devices is large.Aiming at this problem,a superimposed pilots transmission scheme is proposed to improve the channel utilization ratio,and the performance for different active device numbers is further improved by optimal power allocation,making the system have good robustness when the number of active devices changes.In this scheme,the first Bp bits of the sent message sequence are used as the index,to select a pair of pilot sequence and interleaver.Then,using the selected interleaver,the message sequence is encoded,modulated and interleaved,and the selected pilot sequence is then superimposed on the interleaved modulated sequence to obtain the transmitted signal.For this transmission scheme,a power optimization scheme based on the minimum probability of error is proposed to obtain the optimal power allocation ratio for different active device numbers,and a two-stage detection scheme of superimposed pilots detection cancellation and multi-user detection decoding is designed.Simulation results show that the superimposed pilot transmission scheme can improve the performance of the unsourced random access scheme based on the preamble sequence by about 1.6～2.0 dB and 0.2～0.5 dB respectively,and flexibly change the number of active devices that the system carries and that it has a lower decoding complexity.关键词
无标识随机接入/叠加导频/多用户检测和译码/功率分配Key words
unsourced random access/superimposed pilots/multi-user detection and decoding/power allocation分类
信息技术与安全科学引用本文复制引用
郝孟男,李颖,宋光辉..叠加导频传输无标识随机接入方案研究[J].西安电子科技大学学报（自然科学版）,2024,51(3):1-8,8.基金项目
国家重点研发计划(2021YFA1000500) （2021YFA1000500）
国家自然科学基金(62131016,62101397) （62131016,62101397）
