rrestrial radio access network) is separated into two elements. The RAN-specific part migrates into the RAN server, whereas the cell-specific control functions become a part of the AP, which connects antenna elements by optical fiber. Cell-specific processing of user traffic (packet data convergence protocol, PDCP; radio link control, RLC; MAC; etc.) is exclusively performed by the AP. The antenna elements are only responsible for signal transmis- sion and reception. Each AP selects some of them to serve a certain mobile terminal (MT) to construct a generalized distributed cell (group cell). This generalized dis- tributed radio access network architecture is presented in Figures 2.1 and 2.2. 2.2.2.1.2 Definition and Construction Method of Generalized Distributed Cell-Group Cell Based on multiantenna transmission techniques, the generalized distributed cell is characterized by several adjacent cells that use the same resources (such as fre- quency, code, or time slot) to communicate with a specific MT and use different resources to communicate with different MTs. The generalized distributed cell is different from the cluster system in current cellular communication systems in that the cells in the cluster use different resources to communicate with MTs. Figure 2.2 describes a typical generalized distributed cell-based wireless com- munication system in which each AP has several separated antenna elements (AEs). © 2009 by Taylor & Francis Group, LLC Evolution from TD-SCDMA to FuTURE (SGSN) lu_cu IP Network- Server- lu Cth lu C*. Figure 2.1 Generalized distributed radio access network. AP1 has 9 AEs and AP2 connects with 10 AEs. If the AEs in the area are indexed by 1-9 and the size of the generalized distributed cell is 3, three generalized distrib- uted cells are connected with AP1 in this area: generalized distributed cell 1 of AEs 1, 2, and 3 area), generalized distributed cell 2 of AEs 4, 5, and 6 (IIIIII area), and generalized distributed cell 3 of AEs 7, 8, and 9 ( area). This is a fixed User A User B Multi-h