Analytical Performance Evaluation of Time-hopping Pulse Position Amplitude Modulation Ir-uwb Systems under Multi User Interference

Trends in modern communication systems place high demands on low power consumption, high speed transmission and anti-interference characteristics. Therefore impulse radio ultra–wideband (IR-UWB) [1] radio systems have recently gained increased popularity. Since IR-UWB symbols are transmitted with short pulses (< 2 ns), in IR-UWB systems, energy has been spread over the frequency bands of up to 10 GHz. UWB pulses have to follow strict regulations concerning power and spectrum restrictions defined by local authorities, like the Federal Communications Commission (FCC) [2] in the USA. Because of power and spectral properties of transmitted UWB pulses, different type of orthogonal pulse shapes are being used to provide higher spectral efficiency [3], [4]. Derivation of Gaussian pulse and modified Hermite pulses (MHP), usually called Hermites [5], provide wide range of variety pulse combinations for IR-UWB transmission and for that reason these are the most common pulse shapes. The state-of-the art in IR-UWB systems presents many applicable modulation methods like Pulse Amplitude Modulation (PAM), PPM, Pulse Shape Modulation (PSM), on-off-keying (OOK), binary phase-shift keying (BPSK) and Pulse Interval Modulation (PIM) [6]. A combination of these modulation techniques (hybrid techniques) can provide system improvements in terms of the error probability, a higher data rate, a less complex receiver or less power consumption. Many hybrid techniques for IRUWB communication systems have been applied recently, such as Biorthogonal Pulse Position Modulation (BPPM) [7], OOK-PSM [8], PPM-PSM [9], hybrid ShapeAmplitude Modulation [10], and Multi Pulse PositionAmplitude Modulation [11]. Since the first time that multiple-access time hopping (TH) UWB systems was