cdma2000 physical layer: An overview

cdma2000 offers several enhancements as compared to TIA/EIA-95, although it remains fully compatible with TIA/EIA-95 systems and allows for a smooth migration from one to the other. Major new capability include: 1) connectivity to GSM-MAP in addition to IP and IS-41 networks; 2) new layering with new LAC and MAC architectures for improved service multiplexing and QoS management and efficient use of radio resource; 3) new bands and bandwidths of operation in support of various operator needs and constraints, as well as desire for a smooth and progressive migration to cdma2000; and 4) flexible channel structure in support of multiple services with various QoS and variable transmission rates at up to 1 Mbps per channel and 2 Mbps per user. Given the phenomenal success of wireless services and desire for higher rate wireless services, improved spectrum efficiency was a major design goal in the elaboration of cdma2000. Major capacity enhancing features include: 1) turbo coding for data transmission; 2) fast forward link power control; 3) forward link transmit diversity; 4) support of directive antenna transmission techniques; 5) coherent reverse link structure; and 6) enhanced access channel operation. As users increasingly rely on their cell phone at work and at home for voice and data exchange, the stand-by time and operation-time are essential parameters that can influence customer´s satisfaction and service utilization. Another major goal of cdma2000 was therefore to enable manufacturers to further optimize power utilization in the terminal. Major battery life enhancing features include: 1) improved reverse link performance (i.e., reduced transmit power per information bit); 2) new common channel structure and operation; 3) quick paging channel operation; 4) reverse link gated transmission; and 5) new MAC states for efficient and ubiquitous idle time operation. This article provides additional details on those enhancements. The intent is not to duplicate the detail- d cdma2000 radio access network specification, but rather to provide some background on the new features of cdma2000 and on the qualitative improvements as compared to the TIA/EIA-95 based systems. The article is focused on the physical layer structure and associated procedures. It therefore does not cover the MAC, LAC, radio resource management [1], or any other signaling protocols in any detail. We assume some familiarity with the basic CDMA concepts used in TIA/EIA-95.