Introduction

This chapter aims to exploit the key finding of Chapter 3 and apply it to the TDD air interface of UMTS (UTRA-TDD). The significant finding of the previous chapter is that ideal synchronisation is not necessarily a prerequisite to obtaining the maximum capacity in a TD-CDMA/TDD network. This has led the author to develop a novel technique which is called the time slot (TS)-opposing method. In this chapter this method is used to develop a centralised dynamic channel assignment (DCA) algorithm.

The approach in this chapter is as follows: first, in section 4.2 a simple centralised DCA algorithm used in a single cell is studied. This investigation aims to find an upper bound of the network performance when combining the TS-opposing technique with a DCA algorithm. Second, in section 4.3 the TS-opposing algorithm is investigated in a cellular TD-CDMA/TDD network. For this approach it is assumed that a group of BSs (following the so called bunch concept (Mihailescu et al., 1999)) is connected to a radio network controller (RNC).

TS-opposing technique applied to a single cell

In this investigation an idealised deployment scenario is assumed to investigate the new TS-opposing mechanism. This means that a TS-opposing algorithm is employed with the aim of improving the capacity only with respect to a single cell. The capacity obtained thereby is then compared with the capacity of an equivalent FDD interface.

A cluster of seven hexagonal cells is assumed with the cell of interest (COI) in the centre.