 consists of the following steps [2]: The MS selects a ranging opportunity using random backoff based on a binary truncated exponential algorithm. iv After selecting the ranging opportunity, the MS chooses a ranging sequence (alternatively known as ranging preamble) from the set of permissible initial ranging sequences. The selected ranging sequence is sent to the BS within the selected ranging opportunity. The binary exponential backoff or truncated binary exponential backoff refers to an algorithm used to space out repeated re-transmissions of the same block of data. As an example, the re-transmission of frames in Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) and Carrier Sense Multiple Access with Collision Detection (CSMA/CD) networks, where this algorithm is part of the channel access method used to send data over these networks. The re-transmission is delayed by an amount of time derived from the slot time and the number of attempts to re-transmit. After n collisions, a random number of slot times between 0 and 2nd - 1 is chosen. For the first collision, each sender might wait 0 or 1 slot times. After the second collision, the senders might wait 0, 1, 2, or 3 slot times, and SO forth. As the number of re-transmission attempts increases, the number of possibilities for delay increases. The "truncated" simply means that after a certain number of increases, the exponentiation stops, i.e., the re-transmission timeout reaches a ceiling, and thereafter does not increase any further [9]. 4.1 IEEE 802. 16m mobile station state diagrams Failed Operation Path Normal Operation Path From Initialization or Idle State Ranging and UL Synchronization To Initialization State or Power ON/ Basic Capability Negotiation MS Authentication, Authorization and Key Exchange Registration with Serving BS To Connected State Initial Service Flow Establishment FIGURE 4-4 Access state procedures in the IEEE 802.16-2009 standard and IEEE 802.16m [3] The BS responds with ranging acknowledgement MAC control message within a