結(jié)合波束形成與發(fā)射分集的閉環(huán)下行發(fā)射方案
A Scheme of Joint Beam-Forming and Transmit Diversity for Closed-Loop Downlink Transmission
-
摘要: 多天線技術(shù)是提高下行發(fā)射性能的一種有效方法。波束形成(BF)和發(fā)射分集(TD)均通過使用多個天線來有效地改善系統(tǒng)性能并提高信道容量。該文提出了一種將BF和TD結(jié)合用于閉環(huán)通信系統(tǒng)的自適應(yīng)下行發(fā)射方案, 它包括適合于慢變信道的分集陣列方法和適合于快變信道的波束形成陣列方法?；究梢愿鶕?jù)實(shí)際的信道狀況自適應(yīng)地調(diào)整發(fā)射方法。文中詳細(xì)地介紹了自適應(yīng)方案的實(shí)現(xiàn)算法,并對算法的復(fù)雜度和適應(yīng)環(huán)境進(jìn)行了分析。仿真結(jié)果證明新方案可以同時獲得BF增益和TD增益,在使系統(tǒng)的誤比特率(BER)性能大幅提高的同時,增強(qiáng)了系統(tǒng)對信道變化的適應(yīng)能力。
-
關(guān)鍵詞:
- 波束形成; 發(fā)射分集; 空時分組碼; 天線陣列
Abstract: Multi-antenna technique is an effective means of improving performance of the downlink transmission. Both Beam-Forming (BF) and Transmit Diversity (TD) which exploit multiple antennas are attractive candidates for improving the system performance and increasing the channel capacity. In this paper, an adaptive downlink transmission scheme combining BF with TD in the closed-loop mode is proposed. And it includes two methods, one uses the diversity antenna array and is suitable for the slowly time-varying channel, and the other uses the BF antenna array and is suitable for fast time-varying channel. The transmitter can adaptively change the transmission mode between two methods according to the actual channel states. The algorithm of the adaptive scheme is investigated in the paper, and the complexity of the algorithm and its applicable environment are also analyzed. The simulation results show that the new scheme can achieve both BF gains and TD gains; while it improves the performance of the Bit Error Rate (BER), it can enhance the adaptive ability to the channel variance of the wireless system. -
Alamouti S M. A simple transmit diversity technique for wireless communications[J].IEEEJ. on Select Areas Commun.1998, 16(8):1451-1458[2]Jongren G, Skoglund M, Ottersten B. Combining beamforming and orthogonal space-time block coding[J].IEEE Trans. on Info.Theory.2002, 48(3):611-[3]Morelos-Zaragoza R H.[J].Ghavami M. Combined beamforming and space-time block coding for high-speed wireless indoor communications. In Proc. the 4th International Symposium on Wireless Personal Multimedia Communications (WPMC01),Aalborg, Denmark.2001,:-[4]Liu J, Gunawan E. Combining ideal beamforming and Alamouti space-time block codes[J].Electronics Letters.2003, 39(17):1258-[5]Lei Z, Chin F P S, Liang Y-C. Space-time block coding for switched beam systems. In Proc. Wireless Communications and Networking, 2003 (WCNC03), New Orleans, LA, 2003:699 -704.[6]Raleigh G G.[J].Diggavi S N, Jones V K, Paulraj A. A blind adaptive transmit antenna algorithm for wireless communications. In Proc.IEEE International Conference on Communications (ICC95),Seattle, Washington, USA.1995,:-[7]Aste T.[J].Forster P, Fety L, Mayrargue S. Downlink beamforming avoiding DOA estimation for cellular mobile communications. InProc. the 1998 IEEE International Conference on Acoustics,Speech, and Signal Processing (ICASSP98), Seattle,Washington, USA.1998,:-[8]3rd Generation Partnership Project (3GPP), Physical layer procedures (FDD). Tech. Spec., 3G TS 25.214 version 3.0.0, Oct.1999. -
計(jì)量
- 文章訪問數(shù): 2265
- HTML全文瀏覽量: 97
- PDF下載量: 885
- 被引次數(shù): 0
下載:
