gth sequence has 2n -1 chips, where n is the number of stages in the shift registers. A The UMTS Network and Radio Access Technology property of the maximal length sequences implies that for an n - stage linear feedback shift register, the sequence repetition period in clock pulses is To = 2n - 1. When a linear feedback shift register generates a maximal sequence, then all its non-zero output se- quences result in maximal sequences, regardless of the initial stage. A maximal se- quence contains 2n-1-1 zeros and 2n 1 ones per period. Other characteristics of PN sequences, e.g. properties of maximal length PN sequences, auto-correlation, cross-correlation, and orthogonal functions are described in Ref. [23]. In the following we review additional WCDMA characteristics, such as power control and soft handover. 2.1.2.5 Power Control Characteristics Accurate and fast power control becomes imperative in WCDMA. It increases network stability and prevents near-far effect (UL) or cell blocking by overpowered MSs. Open loop or slow power control would not cope with the highly non-correlated fast fading be- tween UL and DL as a consequence of the large frequency separation. Chapter 4 describes the technical details of fast power control. The latter applies to both the UL and DL. In the 1st case, the BS balances the MS's power after comparing the received Signal-to- Interference Ratio (SIR) to a SIRtarget In the 2nd case, we aim to provide sufficient addi- tional power to MSs at the cell edges in order to minimise other-cell interference. The outer loop or slow power control adjusts the BS's reference SIR target based needs of a single or independent radio link. It aims to maintain constant quality estab- lished by the network through a target BER or FER for example. The RNC handles the command steps to lower or increase the reference SIR target- 2.1.2.6 Soft Handovers Characteristics While there is hard handover for carrier change or hierarchical cell transition, and inter- system hand over to pass from FDD to TDD or GSM, in