D FIVE TASK GROUP DOCUMENT GROUP LETTER BALLOT NESCOM CRITERIA BALLOT RECIRCULATION RECIRCULATION REFINEMENT AND COMMENT AND COMMENT RESOLUTION RESOLUTION Review ballot NesCom & comments, modify Call for Interest Standards Board Review proposals draft (CFI) review as needed Standards Board approval Recirculation Study Group Investigates Start work in Create and and disapprove forming a project refine draft comment Working Group resolution Produce PAR and 5 Criteria No changes and no new disapproves, 75% approveland Working Group approves Working Group Working Group forwarding to sponsor ballot? ballot EC review EC approves Forward PAR to NesCom FIGURE 1-5 The IEEE 802 standardization process [32] 1.2 Introduction to the IEEE 802. 16 standards IEEE 802.16 standard in December 2005, when the IEEE 802.16e project was accomplished and was refined and improved through a series of corrigenda and amendments (see Table 1-4). Therefore, the IEEE 802.16 standards have evolved from line-of-sight (LOS) single-carrier fixed- wireless technology to Non-LOS (NLOS) multi-carrier mobile broadband wireless technology over the past decade. 1.2.1 Evolution of the IEEE 802.16 Standards The amendments and revisions of the IEEE 802.16 standard have preserved the essence of their base standards. Various physical layers were combined with the original IEEE 802.16 standard medium access control protocols (i.e., single carrier, OFDM 256, and OFDMA physical layers); however, depending on the capabilities of the physical layer, some changes in the data link layer protocols were made (e.g., handover and power management schemes were added to support mobility in IEEE 802.16e). The principles of IEEE 802.16 data link layer protocols were inherited from DOCSISvi standard. While this philosophy might have worked well for the fixed versions of the IEEE 802.16 standard, it has caused some inefficiency in support of mobility in the later amendments/revisions of the standard. The evolved IEEE 802.16 standards have not necessarily maintained backward 