e wireless base station (WBS) and multiple user terminals (UTs). For each basic WBS there is an RF channel that can provide up to 64 combined TDMA and CDMA code channels. These can be combined to provide a user data rate of up to 2 Mbps. The RF carrier with sidebands occupies around 1.1 MHz at the - 3 dB point, and a 300 kHz guard band is allowed between neighbouring channels to allow adjacent channels to be used in the same cell. Two types of modulation are used. For data being transmitted at less than 384 kbps QPSK is used, but for rates above this it is modified for 16QAM. Each of the RF channels has eight TDMA slots and then for each of these it is possible to have 16 CDMA code channels by providing the 16 CDMA orthogonal codes. The CDMA codes are generated from specific Walsh codes, and then a further pseudo-random spreading code is applied. The system uses what is termed synchronous CDMA. This arises from the fact that to enable a very high level of interference reduction between mobiles, the spreading sequences are very accurately synchronized at the WBS. It is claimed that this virtually removes the co-channel interference from other code channels. In line with other cellular systems a number of 'channels' are defined to carry the various types of information required. Four common channels are defined, namely the Broadcast Control Channel, Forward Access Channel, Paging Channel and the Random Access Channel. The Cellular telecommunications 281 dedicated channels include the Dedicated Control Channel and the Dedicated Traffic Channel. Looking at the channels individually, the Broadcast Control Channel is a downlink channel that is used to broadcast system and cell specific information as well as messages such as time, weather, public informa- tion, etc., to the users in the cell. The Forward Access Channel is a downlink channel used to carry control information to a UT after the uplink access control signal is received. The channel may also carry short packets of information for the user. The Paging Channe