采用空時擴譜技術的CDMA系統(tǒng)在多用戶多徑條件下的性能
The Performance of CDMA Systems withSpace-Time Spreading Approach underthe Conditions of Multi-users and Multipaths
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摘要: 該文研究了多用戶多徑條件下采用空時擴譜(STS)技術的CDMA系統(tǒng)的性能。該STS設計方案在基站使用兩天線陣元,在移動終端使用一全向天線，與一新型擴譜算法聯(lián)合使用，可提高下行鏈路的性能。與現(xiàn)有的研究不同的是，該文在單用戶STS設計方案的基礎上，進一步研究了多用戶的情況，給出了理論分析和誤碼率的表達式。通過仿真結果表明，這種方案相對于傳統(tǒng)方案，性能有一定提高，可有效降低誤碼率，改善下行鏈路的接收質量，但系統(tǒng)實現(xiàn)的復雜性增加，對移動臺有較多的技術要求，STS技術有待進一步完善。
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關鍵詞:
- 空時擴譜; 發(fā)射分集; 多徑接收
Abstract: The paper studies the performance of CDMA systems with the space-fcime ap-proach under the conditions of multi-users and multipaths. The space-time spreading scheme with a novel algorithm can improve the downlink performance by using two antenna elements at the base station and one antenna at the mobile terminal. Different from the present other results, the multi-user systems have been analyzed, the detailed theory analysis and expression of bit-error-probability have been provided, based on the scheme of single-user systems. Moreover, the simulation results show that this scheme obtains an improvement of the CDMA system performance comparing to the conventional approaches, demonstrat-ing that it is a practical way to decrease the bit error rate and improve the qiiality of the downlink of CDMA systems. Meantime, the implementation complexity of the systems has increased, there are many new technical requirements for mobiles to be satisfied, and the STS technique needs to be improved. -
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