nel transmission is the same as for the traffic channel. Multiple users are allowed to share a control LRU. The effective number of data sub-carriers in an LRU depends on the number of allocated pilots and control channel information fields. The distributed resource units contain a group of sub-carriers that are spread across distributed resource allocations within a frequency partition. The size of the DRU is equal to that of the PRU. The minimum unit for forming the DRU in the uplink is a tile. The uplink tile size is 6 X Nsym, where Nsym is the number of OFDM symbols in the uplink subframe. The UL multi-cell resource mapping consists of sub-band partitioning, mini-band permutation, and frequency partitioning, similar to the procedure described for the downlink. The PRUs are first divided into sub-bands and mini-bands as illustrated in Figure 9-23. Similar to downlink subchannelization, a sub-band comprises N1 adjacent PRUs and a mini-band consists of N2 adjacent PRUs where N1 = 4 and N2 = 1. The sub-bands are suitable for frequency- selective allocations as they can provide a continuous allocation of PRUs in the frequency-domain. The mini-bands are suitable for frequency-diversity allocations and are permuted in the frequency-domain. The number of sub-bands is denoted by KSB. The number of PRUs allocated to sub-bands is LSB = N1 X KSB. The Uplink Sub-band Allocation Count (USAC) parameter is used to determine the value of KSB, depending on the system bandwidth. The USAC parameter is broadcast via the secondary superframe header. The remaining PRUs are allocated to mini-bands. The number of mini-bands in an allocation is denoted by KMB. The number of PRUs allocated to mini-bands is LMB = N2 X KMB. The total number of PRUs is NPRU = LSB + LMB. The maximum number of sub-bands is given by the Nsub where Nsub = NPRU/N1. The relationship between USAC and KSB values for system bandwidths of 5, 10, and 20 MHz are given in reference [2]. The PRUs in the uplink are partitioned and reordered into two groups of sub-band P