Experimental results for extensions to the IS-136 TDMA standard based on higher level modulation, coherent detection, and equal gain antenna combining

In previous work, techniques for improved end-user data rate extensions to the IS-136 North American TDMA standard were presented. These techniques were studied for operations in an indoor environment, particularly focused on the downlink (base station to terminal) channel. The indoor channel, with its slow fading characteristics, places special constraints on the system design, which were addressed through handset preselection antenna diversity and improved coding techniques. The work presented in this paper is twofold: to be able to demonstrate a complete end-to-end system, an enhanced IS-136 uplink had to be added to the prototype, leading to investigation of different methods of timing synchronization and diversity combining. In addition, previous standards activities have extended the scope of the original work to address operation in outdoor cellular environments where other receiver techniques were investigated