Combination of OFDM and CDMA for high data rate UWB

Abstract

For Wireless Personal Area Network (WPAN) systems, resource allocation between several users within a piconet and the coexistence of several piconets are very important points to take into consideration for the optimization of high data rate Ultra Wide Band (UWB) systems. To improve the performance of the Multi Band OFDM (Orthogonal Frequency Division Multiplex) solution proposed by the Multi Band OFDM Alliance (MBOA), the addition of a spreading component in the frequency domain is a good solution since it makes the resource allocation easier and also offers a better robustness against the channel frequency selectivity and narrowband interferences. The Spread Spectrum -Multi Carrier -Multiple Access (SS-MC-MA) system proposed in this paper offers not only the advantages of Multi Carrier -Coded Division Multiple Access (MC-CDMA) brought by frequency spreading but also a more effective dynamic resource allocation in a multi-user and multi-piconet context. These improvements are obtained without increasing the complexity of the radiofrequency part compared to the classical MBOA solution. RésuméPour les systèmes WPAN (Wireless Personal Area Networks), la gestion des ressources entre plusieurs utilisateurs d'une même picocellule ainsi que la co-existence de plusieurs picocellules sont des points importants à prendre en compte lors de l'optimisation d'un système Ultra Large Bande (ULB) haut débit. Afin d'améliorer les performances de la solution Multi Band OFDM (Orthogonal Frequency Division Multiplex) proposée par l'alliance MBOA (Multi Band OFDM Alliance), l'ajout d'une composante d'étalement selon l'axe fréquentiel s'avère une bonne solution pour faciliter la gestion des ressources, qui offre en outre une meilleure robustesse vis-à-vis de la sélectivité en fréquence du canal et des interférences à bande étroite. Le système SS-MC-MA (Spread Spectrum -Multi Carrier -Multiple Access) que nous proposons, bénéficie non seulement des avantages du MC-CDMA (Multi Carrier -Coded Division Multiple Access) apportés par l'étalement fréquentiel mais permet également une allocation dynamique des ressources plus efficace dans un contexte multi-utilisateurs et multi-picocellules. Ces améliorations peuvent être obtenues, sans augmenter la complexité du segment radiofréquence par rapport à la solution MBOA.

WITHDRAWN: A Survey on the Performance Analysis of NOMA-Assisted Cognitive Radio Sensor Networks

“…The computational requirements, in terms of the number of multiplications and additions, have been summarized as follows [40][41] [42].…”

Combination of OFDM and Spread Spectrum for High Data Rate UWB: optimization of the spreading length

“…The analytic expression of the SI power associated to the data hk(t) Xk E ak(z, b)0 (t -Tk(z) -Tk(z, b)) (5) j for the case of a synchronous SS-MC-MA transmission is z= b=O given by:…”