This proposal outlines the requirements for developing an enabling technology referred to as Ultra Wideband Multicarrier Code Division Multiple Access (also known as UW-CDMA). UW-CDMA will emerge as the ultra-wideband wireless backbone for the mobile industry, enabling a substantial increase in bandwidth for low-cost hand-held communication devices.
The development of UW-CDMA will redefine the bandwidth paradigm by transforming wireless bandwidth from a scarce resource into an available commodity. This transformation will occur when UW-CDMA provides communication channels through which wireless services are delivered. Service providers will employ UW-CDMA to deliver services based on market demands. Bandwidth will be traded as a commodity which can be purchased in advance, or at the time of demand. For example, a wireless service provider who wants to offer video conferencing services (1) purchases bandwidth at low cost from a UW-CDMA network, (2) develops the wireless video conferencing services he wants to offer customers, and (3) sells his service to his customers. This allows wireless-service providers to focus on the services provided to end users with a guaranteed bandwidth for delivering their service.
A UW-CDMA network provides a large number and variety of communication services because UW-CDMA:
1. offers ultra-wide bandwidth in a market traditionally limited to small, high-cost frequency bands; and 2. provides superior performance in the most challenging conditions, including multipath fading.
UW-CDMA provides ultra-widebandwidth by using multiple frequency bands simultaneously. For example, UW-CDMA can occupy the three unlicensed frequency bands in the ranges of 902-928 MHz, 2400-2485 MHz, and 5725-5850 MHz, and not interfere with the licensed frequencies between these bands. UW-CDMA fills available gaps in the frequency spectrum to enable ultra-wideband services, and UW-CDMA can provide these services without requiring expensive, high-frequency microwave components.
UW-CDMA provides frequency diversity and improved signal quality by redundantly transmitting information signals on different carrier frequencies. However, this redundancy does not diminish the bandwidth efficiency. In fact, superior bandwidth efficiency is achieved because the carriers combine to produce signals that are orthogonal in the time domain. As a result, each user attains the performance of N-fold frequency-diversity gain, where N is very large.
Multiple users share the UW-CDMA wireless connection by use of a sophisticated version of multiple carrier-code division multiple access (MC-CDMA). In each frequency band in which a user transmits a signal, an applied phase is employed as part of a spreading code. The collection of all applied phases acts as the spreading code. Complex phases are applied such that desired signals are received and combined to create the N-fold diversity gain, whereas undesired signals cancel.
This proposal outlines the development of UW-CDMA. Successful completion of this project will bring the dream of anytime, anywhere, anything wireless access one giant leap closer to reality. ***
