Đang chuẩn bị liên kết để tải về tài liệu:
Các mạng UTMS và công nghệ truy cập vô tuyến P8

RESOURCE AND NETWORK MANAGEMENT INTRODUCTION Operating a 3G network involves managing resources and Network Elements (NE). This chapter covers these two aspects to complete the deployment issues started in Chapter 7. Resources here refer primarily to the radio resources and NE refers to the 3G building blocks, i.e. elements in the CS, PS and radio access networks. | The UMTS Network and Radio Access Technology Air Interface Techniques for Future Mobile Systems Jonathan P. Castro Copyright 2001 John Wiley Sons Ltd Print ISBN 0-471-81375-3 Online ISBN 0-470-84172-9 Q Resource and Network Management 8.1 Introduction Operating a 3G network involves managing resources and Network Elements NE . This chapter covers these two aspects to complete the deployment issues started in Chapter 7. Resources here refer primarily to the radio resources and NE refers to the 3G building blocks i.e. elements in the CS PS and radio access networks. 8.2 Radio Resource Management and Signalling Power control constitutes one of the major tasks of Radio Resource Management RRM . Other tasks such as admission control load control and packet scheduling also correspond to RRM however we will not emphasize them in this section. Power control aims to minimize interference levels in order to maintain an expected transmission quality in the air-interface. The UTRA FDD mode depends on soft blocking to efficiently manage multi-rate services. This takes place according to appropriate RRM algorithms covered in Chapter 4. 8.2.1 Managing Power Power control becomes more critical in the FDD than in the TDD mode. Thus this section concentrates primarily on managing power in WCDMA. The impacts on handover are also presented. In WCDMA all users share the same RF band separated by spreading codes. As a result each user appears as a random noise to other users. Non-controlled individual power can therefore interfere unnecessarily with those sharing the same frequency band. To illustrate the need for power control Figure 8.1 shows two MSs in the UL. MS1 gets closer to the BS than MS1 now if there was no power control both MSs would transmit at their fixed power PT. But since MS1 is closer it would have higher power than that of MS2 if we assume that the distance of the latter is three times greater than that of MS1. Thus if the required SNR S Nrequired is 1 3 then S N1 3 .