ies the left-most segment of the spectrum among a number of contiguous RF carriers, the number of guard PRUs in the left edge of the carrier is zero. Furthermore, when an RF carrier occupies the right-most of segment of the Outer Permutation: Stage 2 Mini-Band Inner Permutation and Outer Permutation: Stage 1 Sub-band Permutation (N1=4) Permutation (N2=1) FFR Partitioning, DRU/CRU LRU Formation Subframe = Nsym OFDM Symbols PRU_1 PRU_2 Contiuous Allocations PRU_3 bands PRU_4 bands Inner Tone-Pair Permutation PRU_N-1 PRU_N-1 PRU_i PRU_N PRU_N Mini- PRU_1 bands PRU_4 PRU_2 PRU_3 PRU_3 Contiuous Allocations PRU_4 PRU_1 PRU_N-1 bands Inner Tone-Pair Permutation PRU_N PRU_2 Subframe = Nsym OFDM Physical Resource Units Symbols Permuted Sub-bands (18xNsym Sub-carriers) Permuted Mini-Bands FFR Groups, DRUs and CRUs Logical Resource Units FIGURE 9-24 An illustration of physical to logical resource mapping 9.8 Subchannelization and permutation CRU(FPo) A Tone 0OP004 A Tone DRU(FPo) 11011 122122 233233 3434P 454454 565565 CRU(FP1) 676676 7P77P7 P88P8 DRU(FP1) Sub-carrier Permutation CRU(FP) DRU(FP2) CRU(FP3) DRU(FP3) FIGURE 9-25 An example of downlink sub-carrier permutation (KSB = 7, FPCT = 4, FPS0 = FPS = 12, DFPSC = 2, DCASSBO = 1, DCASMBO = 1, DCAS = 2, Idcell = 2, BW = 10 MHz, and 2 spatial streams) [2] CHAPTER 9 The IEEE 802. 16m Physical Layer (Part I) RF Carrier N-1 RF Carrier N RF Carrier N+1 Integer Multiple of Sub-carrier Spacing Integer Multiple of Sub-carrier Spacing Guard Bands Logical Resource Units FIGURE 9-26 An example of data transmission using guard sub-carriers [2] spectrum among a number of contiguous RF carriers, the number of guard PRUs in the right edge of the carrier is zero [2]. The left and right guard PRUs are denoted as G-PRUL[0], G-PRUL[2], G-PRUL[NLG-PRU - and G-PRUR[0], G-PRUR[0], G-PRUR[NRG-PRU - 1], respectively, from the lowest frequency index. The guard PRUs are indexed by interleaving G-PRUL and G-PRUR, i.e., G-PRU[i] = G-PRUL[i/2] for even-valued i and G-PRU[i] = G-PRUR[(i 1)/2] for odd-