摘 要

在TD-SCDMA系统中，有一个问题，非急救语音服务掉线概率不理想时，我们使用动态分配算法。为了解决这个问题，我们提出了一种新的算法，它被称为保护信道预留队列移动边界动态信道分配。该算法在预留信道的情况下，对非紧急语音服务服务的调用，以保持阻塞概率为服务，引入无患者客户，并结合数据包进行借阅。仿真结果表明，与移动边界算法相比，该算法降低了非紧急话音业务的丢包率，维护了多种业务的阻塞概率，减少了数据包丢失的概率数据业务。

当这项研究开始，TD-SCDMA（时分同步码分多址）仍在研发阶段，但现在，这项技术已被广泛使用。然而，在我国的TD-SCDMA试验期间，从2006年开始，一些干扰问题已经在网络规划和初始化阶段特别受到关注。干扰一直是一个问题，在任何网络和本论文的工作目标都是在有干扰的情况下提高网络覆盖和容量。本文基于TD-SCDMA网络的工作原理及干扰的形成原因，对传统N频技术的网络提出了改进。本文引入的同心圆蜂窝的概念，并加入一个中继网络，使其他用户可以利用蜂窝的边缘。这种整体的方法不仅优化了抗干扰的能力，并且在不增加更多节点基站的前提下增加了网络覆盖。

关键词：TD-SCDMA；可移动边界动态信道分配；不耐烦顾客；信道保留

Abstract II

摘要 III

Chapter 1 Introduction

1.1 Introduction of TD-SCDMA 1

1.2 3G Mobile Networks 3

Chapter 2 Radio Access Technique in TD-SCDMA

2.1 The Frame Structure of TD-SCDMA 7

2.2 Combined TDMA/TDD and CDMA operation 8

2.3 Joint Detection in TD-S CDMA 9

2.4 Smart Antennas 10

2.5 Dynamic Channel Allocation 11

2.6 Terminal Synchronisation 12

2.7 N-Frequency in TD-SCDMA 13

2.8 Concentric Circles Cell 14

2.9 Multi-carrier HSDPA in TD-SCDMA 15

2.10 Relay Networks 16

2.11 Summary 18

Chapter 3 A Dynamic Channel Allocation in TD-SCDMA System

3.1 Queue Movable Boundary Dynamic Channel Allocation Algorithms 19

3.2 The Design Ideas of Channel Reservation Movable Boundary Algorithm 20

3.3 Performance Analysis 22

3.3.1 New User Access 22

3.3.2 Loop Detection 23

3.4 Simulation Results and Analysis 23

3.4 Conclusion 29

Abbreviations 30

References 33

Acknowledgements 35

Chapter 1

Introduction

1.1 Introduction of TD-SCDMA

TD-SCDMA mobile communication system is the first generation system of telecommunications technology in China which has independent intellectual property rights. In TD-SCDMA system, many key technologies are used, including duplex time division, smart antennas, joint detection and dynamic channel allocation, etc. Among these technologies, the dynamic channel allocation played an important role in reducing interference, increasing system capacity and improving the quality of service, so that the limited sources can well serve the growing number of user. According to the 3GPP standard, DCA can be divided into slow dynamic channel allocation (SDCA) and fast dynamic channel allocation (FDCA). SDCA refers to allocate resources to cells in TD-SCDMA system, while FDCA is allocate resources for the user of application access, and according to the system status the resources to be adjusted, which have been allocated.

At present, the system of TD-SCDMA study of the allocation of fast dynamic channel mainly concentrated in the high-priority voice service, mobile border algorithm, call allocation priority handoff channel strategies, through the slot allocation algorithm based fast dynamic channel interference. There are a few research on TD-SCDMA system in another country, because it was raised originally TD-SCDMA system in China, and the search for channel allocation in this system is still not deep. At present, it is more research on the method of allocation of channel strategy movable border [1]. This method is M.J.Fisher and others. The World Health Organization put forward in the future allocation of dynamic mobile border channel strategy (MB_DCA) which is suitable for applications of wireless communications system.

In this strategy, all time slots are divided into two parts which are data service time slots and voice service time slots. When service transfer is processing, if the voice service time slots are idle, data service datapackets in the buffer queue can be transmitted by borrowing the voice service time slots. But when a voice call comes in, the voice service can seize the voice time slots borrowed by data services for voice communications. Then a hybrid data rate, small grouping borrowed MB_DCA algorithm (MRG_MB_DCA) has been proposed , compared with the original MB_DCA, on the base of not affecting the probability of call blacking, this algorithm reduces the probability of data packet loss and improves the system resources utilization, but the article has not considered the voice service priority; based on MRG_MB_DCA channel reserved for handoff calls, the PCR_MB_DCA has been proposed , the algorithm reduces the blocking probability of voice handoff calls and improves the performance of data services; queue movable boundary dynamic channel allocation (QMB_DCA) has been proposed, it reduces probability of blocking and probability of dropped call in low priority service, but the probability of dropped call in high priority service does not improve.

To solve these problems, it is proposed allocation of movable garrison dynamic channel Canal ease queue limits (PCR_QMB_DCA), the algorithm improves the queue movable border allocation of the vital channel (QMB_DCA). Algorithms PCR_QMB_DCA reserved channels for the service call dropped, which dropped voice non-emergency call service, which reduces the possibility of inviting declined for voice calls. Since the client PCR_QMB_DCA gave no patience, so as to ensure the possibility of obstruction unchanged on the basis of the smallest decline prospect. Taking into account the level of the different services of data and different possibilities service, and reduce the loss of possibilities package.

One of the main challenges for 3G mobile systems is mastering both symmetric circuit switched services (such as speech or video) as well as asymmetric packet switched services such as mobile Internet access. To face this challenge, TD-SCDMA combines two technologies: an advanced TDMA/TDD system with an adaptive CDMA component operating in synchronous mode.

This section outlines the basic technological principles on which the TD-SCDMA technology is based :

• TDD (Time Division Duplex) allows uplink and downlink of the link on the same bandwidth and does not require associated with gangs. In TDD, and moves in the uplink and downlink frequency channel link itself, but at different times [2]. It is possible to change the shift points duplex and transfer power from the transmission to the descending or vice versa, so better use of the spectrum. It allows symmetric and asymmetric data services.

• TDMA (Time Division Multiple Access) is a digital technique that divides each frequency channel into multiple time-slots and thus allows transmission channels to be used by several subscribers at the same frequency.