On the power spectral density of UWB signals in IEEE 802.15.3a

Abstract

Ultra Wide-Band (UWB) radio uses base-band pulses of very short duration, thereby spreading the energy of radio signal very thinly over gigahertz. Power Spectral Density (PSD) of UWB signals consists of continuous and discrete components. Since the discrete component contributes more to PSD than continuous component, it presents greater interference to other narrow-band wireless systems. UWB was approved by the FCC for commercial deployment in 2002. In order to ensure negligible mutual interference, the FCC has specified emission limits for UWB applications. UWB is now under consideration as an alternative physical layer technology for wireless PAN in IEEE 802.15.3a. However, little study has been reported on PSD issues in IEEE 802.15.3a. This paper presents analysis on PSD of UWB signals in IEEE 802.15.3a systems, and on what frame reversion can achieve in reducing the PSD.

Performance Comparison of UWB Pulse Modulation Schemes under White Gaussian Noise Channels

“…In this work, we assumed L = 1 (no losses in the system hardware). The pulse waveform is the 5th derivative of a monocyclic Gaussian pulse and its PSD is given by [13] …”

“…where N 0 is the thermal noise power, SNR spec is the system requirement SNR, and H( f ) is the frequency response of the indoor channel, which can be expressed as [13] …”

Comparisons of various pulse shapes for DS-UWB signals over the UWB channel

“…The difference between the DS-UWB signal and the conventional DSSS signals is that DS-UWB signals has no carrier and pulse shaping waveforms are band-pass signals. The below equation gives the PSD of a bipolar DS-UWB signal for a single user using random bits and chips Mo and Gelman [13],…”

“…The SNR for the reference path in (10) is independent from the user, i.e., it is the same for any user, and can be written as (13) where (α r ) is the random variable with log normal distribution, and all other terms are deterministic. Hence, the SNR of a path γ r is a random variable with log normal pdf given by Simon and Alouini [24] p γ r (γ r ) = 10/ ln 10 √ 2πσ 2 γ r exp − (10 log 10 γ r − μ r ) 2 2σ 2…”

Analysis of power spectral density of ultra wideband waveforms for pulse shape modulation

“…However, PSD of baseband modulation for a time-hopped sequence of UWB pulse shapes consists of continuous and discrete components. The discrete components do not convey any information but cause PSD to increase (Mo and Alexander, 2004). These spikes are to be reduced by proper design of UWB pulse shapes so as to conform to the FCC regulations.…”