【作者】 沈嵩辉；

【导师】 张英海； 王卫东；

【作者基本信息】 北京邮电大学 ， 微电子学与固体电子学， 2009， 硕士

【摘要】 随着通信技术的不断发展,移动通信的业务种类日益丰富,高速数据业务在未来移动通信系统中占有越来越大的比重,而高速数据业务具有上下行传输速率不对称的显著特点。不仅如此,随着数据传输速率的提高,所需的发射功率也相应提高,对人类和环境的影响也越来越大。研究表明:在电磁辐射限制下,上行链路的传输速率容易受限,而下行链路的传输速率存在较大裕量,下行链路的传输速率可以远大于上行链路。双工技术决定了通信系统上下行资源的分配,所以研究适应非对称传输的双工技术具有非常重要的意义。频分双工(FDD)和时分双工(TDD)是现代移动通信系统的两大双工方式。FDD系统通过上下行链路使用两个不同的频段来实现上下行之间的通信,保持信道的正交性;而TDD系统的上下行链路使用同一个频段,通过不同的时隙来区分上下行,可以通过动态调整上下行时隙数目来调整上下行资源的分配,但存在严重的交叉时隙干扰。为了适应未来移动通信中的非对称特性,本课题主要研究适应非对称传输的FDD双工技术,设计了一种新型的非对称频分双工AFDD(Asymmetric Frequency Division Duplex),它可以根据每个小区实际业务情况,动态调整小区中的使用频点。这种情况下,配对使用的上、下行频点之间的频率间隔也动态变化,有可能会出现配对使用的一对频点由于频率间隔太小而造成上下行之间强烈干扰的情况。针对这种情况,本文设计了一种双工频率动态映射下的频率对匹配方案,可以实现较灵活的频率对匹配,提供更多的满足隔离要求的双工频率对,能够更好地满足未来移动通信系统业务多样化、呈现非对称特性的需求。同时,本文又对双工频率动态映射的AFDD系统进行了动态频率对匹配建模和其性能分析,从分析可以看出,AFDD相比传统的对称型FDD系统具有明显的优越性,能够提高频谱利用率,降低新接入用户的阻塞率,增强系统鲁棒性。更多还原

【Abstract】 With the development of communication technology, a greater and greater variety of mobile communication services turn up, and the high date rate traffics play more and more important part in future communication system, which have strong asymmetric characteristic between the uplink (UL) and downlink (DL) data rate. Furthermore, with increase of data rate, the transmission power is also enhanced and the impact on human and environment is growing. By calculation it shows that: under the restriction of electromagnetic radiation, the uplink transmission rate is easily limited, while the downlink rate has much margin, which can be much higher than the uplink transmission rate.Duplex technology is the way to achieve the resource allocation between UL and DL. Existing duplex schemes in present mobile communication systems include frequency division duplexing (FDD) and time division duplexing (TDD). In FDD scheme, the UL and DL signals are transmitted using different frequency bands, which are separated by a guard band. Meanwhile, in TDD scheme, the UL and DL signals are transmitted over the same frequency band but different time slots. TDD scheme has the advantage of flexibly adjusting UL and DL bandwidth by allocating different numbers of time slots. Yet, the crossed timeslot interference problem is very severe.To adapt to the asymmetric characteristic of future communication system, this paper has been analyzed and researched on relative asymmetry-adptive FDD technique. A novel asymmetric frequency division duplex (AFDD) is proposed, which can dynamically allocate the frequency points use according to the actual service circumstance. On this condition, the frequency distance between the matched UL and DL frequency points is also dynamically changing, and probably interference each other because of low frequency distance.Therefor, this paper proposes a duplex frequency-pair matching scheme based on dynamic frequency mapping, which can achieve flexible frequency-pair matching, and provide much more frequency-pairs which are met the separation requirement. It can well meet the service diversity and asymmetric characteristics. Furthermore, this paper establishes a model of frequency-pair dynamically matching. From the analysis it can see that: compared with FDD system, AFDD has great advantages, which can improve the frequency use ratio, decrease the new users’ block probability, and enhance the system robustness.更多还原