Multiple-Access Slightly Frequency-Shifted Reference Ultra-Wideband Communications for Dense Multipath Channels

The design of ultra-wideband (UWB) communication systems has proven to be challenging. Coherent systems require a rake receiver with many taps that is difficult to train, and transmitted-reference (TR) schemes require a wideband analog delay line whose implementation has proven extremely difficult. In response to this challenge, we have recently proposed the frequency-shifted reference (FSR-UWB) system, which leads to the replacement of the delay line in the receiver of the standard TR-UWB system with a mixer, and the resulting system is easily implemented. In this paper, the FSR-UWB idea is extended to provide multiple-access, and a performance analysis is presented. This analysis and the corresponding numerical results reveal that, due to the large bandwidth expansion of the UWB system, the FSR-UWB single-user receiver can still be successfully employed in lightly loaded systems; in other words, successful multiple- access can be achieved without the need for the wideband analog delay line of TR-UWB or the despreading circuitry generally associated with conventional multiple-access spread-spectrum systems. The result is an extremely simple architecture for wideband multiple-access communications in the wireless environment.

[1]  A. Dentinger,et al.  Delay hopped transmitted reference experimental results , 2002, 2002 IEEE Conference on Ultra Wideband Systems and Technologies (IEEE Cat. No.02EX580).

[2]  Dennis Goeckel,et al.  Slightly Frequency-Shifted Ultra-Wideband Radio , 2006 .

[3]  Zhengyuan Xu,et al.  A multiuser transmitted reference UWB transceiver for high data rate communication , 2005, MILCOM 2005 - 2005 IEEE Military Communications Conference.

[4]  R. Hoctor,et al.  Delay-hopped transmitted-reference RF communications , 2002, 2002 IEEE Conference on Ultra Wideband Systems and Technologies (IEEE Cat. No.02EX580).

[5]  Lei Feng,et al.  An oversampled channelized UWB receiver with transmitted reference modulation , 2006, IEEE Transactions on Wireless Communications.

[6]  Dennis Goeckel,et al.  Slightly Frequency-Shifted Reference Ultra-Wideband (UWB) Radio , 2007, IEEE Transactions on Communications.

[7]  Mario R. Casu,et al.  Implementation aspects of a transmitted-reference UWB receiver: Research Articles , 2005 .

[8]  D.L. Goeckel,et al.  FSR-UWB (TR-UWB without the Delay Element): Effect of Impulse Dithering and Experimental Results , 2006, 2006 IEEE International Conference on Ultra-Wideband.

[9]  Robert A. Scholtz,et al.  Multiple access performance of ultra-wideband transmitted reference systems in multipath environments , 2004, 2004 IEEE Wireless Communications and Networking Conference (IEEE Cat. No.04TH8733).

[10]  Moe Z. Win,et al.  Ultra-wide bandwidth time-hopping spread-spectrum impulse radio for wireless multiple-access communications , 2000, IEEE Trans. Commun..

[11]  Mario R. Casu,et al.  Implementation aspects of a transmitted-reference UWB receiver , 2005, Wirel. Commun. Mob. Comput..

[12]  D. L. Goeckel,et al.  Slightly frequency-shifted reference ultra-wideband (UWB) radio: TR-UWB without the delay element , 2005 .