 TSEQ. There are five random access preamble formats CHAPTER 9 The IEEE 802. 16m Physical Layer (Part I) specified by the standard, as shown in Table 9-26, where the parameter values depend on the frame structure and the random access configuration. Higher layers control the preamble format. Each random access preamble occupies a bandwidth corresponding to six consecutive resource blocks for both frame structures. The transmission of a random access preamble, if triggered by the MAC layer, is restricted to certain time and frequency resources. These resources are enumerated in increasing order of the subframe number within the radio frame and the physical resource blocks in the frequency domain, such that index 0 correspond to the lowest numbered physical resource block and subframe within the radio frame. The random access preambles are generated from Zadoff-Chu sequences with a zero correlation zone. The network configures the set of preamble sequences the UE is allowed to use. There are 64 preambles available in each cell. The set of 64 preamble sequences in a cell is found by including first, in the order of increasing cyclic shift, all the available cyclic shifts of a root Zadoff-Chu sequence with the logical index RACH_ROOT_SEQUENCE, where RACH_ROOT_SEQUENCE is broadcast as part of the system information [107]. The random access procedure in 3GPP LTE consists of four steps. In step 1, the preamble is sent by UE. The time/frequency resource where the preamble is sent is associated with a Random Access Radio Network Temporary Identifier (RA- RNTI). In step 2, a random access response is generated by the eNB and sent on the downlink shared channel. It is addressed to the UE using the temporary identifier and contains a timing advance value, an uplink grant, and a temporary identifier C-RNTI. Note that the eNB may generate multiple random access responses for different UEs which can be concatenated inside one MAC protocol data unit. The preamble identifier is contained in the MAC sub-header of each random acces