Challenges in low-cost wireless data transmission

Second- and third-generation (2G and 3G) wireless systems have been designed primarily for voice, a connection-oriented, delay-sensitive service requiring a specified bit rate. In contrast, data services are often connectionless, delay insensitive, and have no specific bit-rate requirements. These differences suggest that ubiquitous (anytime/anywhere) coverage may not be a strict requirement for wireless data networks and in fact may needlessly complicate the design. This line of thought leads to systems that provide isolated high bit-rate "pockets" of coverage close to base station antennas through multilevel modulation and increased spectrum reuse allowed by pocket isolation. Specific issues that are relevant for such tier architectures range from the physical layer extending to radio resource management and even application layers. We describe some issues for wireless data targeting the following: transceiver techniques and radio resource management.