st. Notification Channel (NCH) The purpose of this channel is to inform the mobile about voice broadcast calls; it operates only to the downlink. Paging Channel (PCH) The PCH channel is used to inform the MS about terminating a call. Random Access Channel (RACH) The RACH channel is for MS access requests and location updates for instance; it operates to the uplink direction only. Dedicated Control Channels Slow Associated Control Channel (SACCH) This is used for monitoring the link, e.g. transmitting the measurements supporting the handover (HO) decision making. The SACCH is always connected to the TCH. The SDCCH, as do all the dedicated control channels, operates in both directions (uplink and downlink) and is a point-to-point channel. Stand-alone Dedicated Control Channel (SDCCH) This channel is used for signalling, e.g. in the call setup phase, for assignment of the traffic channel and in location updates. Fast Associated Control Channel (FACCH) This channel is used in critical signalling cases; it takes the burst from the TCH to transmit signalling. The critical situation is, for example, the handover. Capacity Enhancement Techniques Capacity enhancement techniques can be used if the required capacity is higher than can be provided by macro cells. One example of enhancement techniques is frequency hopping. The theory will be explained in the frequency planning section (Section 2.7.3). Micro and pico cells are another example of how to offer extra capacity. Radio Network Planning and Optimisation 2.6.2 GPRS and EGPRS Capacity Planning The following sections consider the dimensioning for a mixed traffic profile of GPRS / EGPRS and GSM voice. Note that GPRS and EGPRS data is able to perform in a discontinuous mode with resources being allocated as and when available (capacity on demand) while GSM voice requires a continuous connection for extended periods (tens of seconds). For the purposes of this discussion, all GPRS examples that are provided can also be directly applied to EGPRS capacity planning. Another im