手机直连低轨卫星通信的低复杂抗频偏PSS检测算法研究OA

For mobile devices directly connected to low Earth orbit(LEO)satellites,primary synchroni-zation signal(PSS)detection,as the initial step of cell search,plays a pivotal role in achieving downlink time-frequency synchronization.The substantial Doppler frequency offsets induced by LEO satellites'high-speed motion severely degrade PSS detection success rates,often leading to failed cell search and synchronization.Current research has not adequately considered the characteristics of this scenario,and the complexity of existing algorithms has not been significantly reduced;instead,in some cases,it has even increased.To address this challenge,this paper proposes a low-complexity PSS detection algorithm with enhanced frequency offset robustness,utilizing differentiated synchronization signal block(SSB)power allocation.The algorithm adopts a dual-rate sampling framework:The first branch operates at the minimum sampling rate to acquire coarse synchronization points through a reverse correlation and thresh-old decision mechanism,while the second branch samples subsequent signal segments at standard rates to achieve precise timing synchronization via a differential-inspired algorithm.Frequency offset compen-sation is implemented through a hybrid strategy—the integer frequency offsets are estimated via FFT,while the fractional frequency offset is estimated by cross-correlation between the front and back seg-ments of PSS.Additionally,a pipeline design is incorporated to reduce computational latency.Simulation results demonstrate that the proposed algorithm demonstrates superior frequency-offset and noise robust-ness.It can achieve a detection success rate of over 90%even at-5 dB signal-to-noise ratio(SNR)with a normalized frequency offset of 5.Compared to conventional methods,it reduces computational complex-ity by over fourfold and significantly accelerates cell search in high-frequency-offset environments.