 with an RCP. When the preamble is repeated as an extended single opportunity, the second RCP is omitted for coverage extension. The guard sub-carriers are reserved at the edge of the non-synchronized physical ranging channel. The use of code-division multiplexing would allow a number of mobile stations to share the same ranging channel. The ranging channel for synchronized mobile stations is used for periodic ranging. The synchronized ranging channel starts at a configurable location (as defined in a downlink broadcast control message) and is frequency-division multiplexed with other control and data channels. In an FDM-based UL-PUSC zone, non-contiguous resource blocks are used for the ranging channel. The ranging channel for FDM-based UL-PUSC zone consists of six distributed LRUs. The transmission of the initial ranging signal by a non-synchronized mobile station is performed within two consecutive OFDM symbols, as shown at the bottom of Figure 10-16. The same ranging code is 10.3 Uplink control channels transmitted on the ranging channel in each OFDM symbol to avoid phase discontinuity between the two symbols. The transmission of the ranging signal by the synchronized mobile stations is performed within an OFDM symbol, as shown in Figure 10-16. The physical layer procedures for generation and detection of the initial ranging sequences are illustrated in Figure 10-17. The ranging preamble codes are grouped into initial ranging and handover ranging preamble codes. The initial ranging preamble codes are used for initial network entry, whereas handover ranging preamble codes are used for ranging with a target base station during handover. For a ranging code opportunity, each MS randomly chooses one of the ranging preamble codes from the available ranging preamble code set in a cell, except in the handover ranging case where a dedicated ranging code is assigned, the MS uses the assigned dedicated preamble code. Zadoff-Chu sequences with cyclic shifts are used to generate the ranging preamble codes for non- synchro