準(zhǔn)同步寬帶CDMA衛(wèi)星移動(dòng)通信分析

【摘要】理想同步CDMA系統(tǒng)具有很高的容量，然而在衛(wèi)星移動(dòng)環(huán)境下很難實(shí)現(xiàn)，一般采用準(zhǔn)同步系統(tǒng)。該文首先仿真分析了準(zhǔn)同步誤差對(duì)寬帶CDMA衛(wèi)星移動(dòng)通信的影響，發(fā)現(xiàn)CDMA系統(tǒng)在準(zhǔn)同步的條件下性能有明顯改觀，也就是說(shuō)在相同條件下能大大提高系統(tǒng)容量。然后針對(duì)衛(wèi)星移動(dòng)環(huán)境提出了一種準(zhǔn)同步實(shí)現(xiàn)策略，并對(duì)其可行性進(jìn)行了論證。通過(guò)分析可以看出該策略是可行的，并且軌道越高實(shí)現(xiàn)越容易。
關(guān) 鍵 詞 準(zhǔn)同步; 衛(wèi)星移動(dòng)通信; 多普勒; 寬帶碼分多址

The system of synchronous CDMA has large capacity, however it is difficult to implement in mobile satellite condition. So we consider establishing quasi-synchronous system. In this paper, the effect of quasi-synchronous error to broadband CDMA mobile satellite system is analyzed through computer simulation. The performance of CDMA system is improved distinctively in the condition of quasi-synchronous. This paper presented one strategy to realize quasi-synchronous in satellite environment, and discussed its feasibility. After analysis, we find that this strategy is feasible and implemented easier with the increase of orbit elevation.