Title :
Achievable information rates of PPM impulse radio for UWB channels and rake reception
Author :
Güney, Nazli ; Deliç, Hakan ; Alagöz, Fatih
Author_Institution :
Dept. of Electr. & Electron. Eng., Bogazici Univ., Istanbul, Turkey
fDate :
5/1/2010 12:00:00 AM
Abstract :
The performance of impulse radio is investigated for ultra-wideband (UWB) channels and orthogonal M-ary pulse position modulation (PPM) in terms of the maximum achievable information rate, where the outputs of the M-ary correlation receiver implemented through the rake structure with conventional maximal ratio combining are subject to either soft or hard decisions. The major difference observed between the soft- and hard-output systems is that at low values of the mutual information the minimum information bit energy to noise ratio required for reliable communication increases with the constellation size for the hard-output systems. Furthermore, it is demonstrated that independent of the type of the output, achievable rates are considerably low at medium-to-large signal-to-noise ratio (SNR) values in UWB channels compared to those in additive white Gaussian noise channels, as the frequency-selectivity of the UWB channel destroys the orthogonality of the transmitted PPM signals. Interference from other users and constellation size put additional constraints on the achievable rates at high SNR.
Keywords :
Gaussian channels; pulse position modulation; radio receivers; telecommunication network reliability; ultra wideband communication; Gaussian noise channels; M-ary correlation receiver; UWB channels; conventional maximal ratio combining; impulse radio; minimum information bit energy; orthogonal M-ary pulse position modulation; rake reception; ultra-wideband channels; Additive white noise; Diversity reception; Frequency; Information rates; Interference; Mutual information; Pulse modulation; RAKE receivers; Signal to noise ratio; Ultra wideband technology; Impulse radio, M-ary PPM, UWB, achievable rate, mutual information;
Journal_Title :
Communications, IEEE Transactions on
DOI :
10.1109/TCOMM.2010.05.080616