eives the relay control channels from the access station in the access zone or in the relay zone, if the RS coexists with a time-division transmit and receive RS, in order to retain synchronization of relay control channels. A time-division transmit and receive RS may maintain its synchronization by listening to the relay preamble transmitted by its super-ordinate station. 4.4 State transitions in relay stations From Initialization State Ranging and Uplink Synchronization To Initialization State Basic Capability Negotiation RS Authentication, Authorization, and Key Exchange Registration with Serving BS Neighbor Station Measurement Report and Access Station Selection To Operational State Configure Relay Operation Parameters Failed Operation Path Normal Operation Path FIGURE 4-19 Procedures in the access state of an IEEE 802.16m relay A simultaneous transmit and receive RS may maintain its synchronization by listening to the frame start/relay preamble of its super-ordinate station. A transparent RS may maintain its synchronization by listening to the preamble transmission from its super-ordinate station. According to the procedures specified in [10], in the Operational State, a non-transparent RS transmits its own frame start preamble at the frame indicated by the Action Frame Number parameter in the RS configuration message [10]. The frame number used by the non-transparent RS with unique BS identification takes into account the RS Frame Offset parameter [10]. If an RS Frame Offset is not provided, the RS uses the same frame number as its super-ordinate station, i.e., the RS considers the RS Frame Offset is zero. The relay frame configuration may be changed during the Operational State in a quasi-static manner using the RS configuration message, or in a dynamic manner using relay frame control header. The Frame Configuration parameter may be transmitted in RS configuration message to CHAPTER 4 IEEE 802. 16m System Operation and State Diagrams indicate the mechanism that must be followed for determining the frame s