A study of DiffServ based QoS issues in next generation mobile networks

To provide data rates of the order of hundreds of Mbps and multimedia services, standardization efforts for next generation (4G) systems are focusing on target technologies and seamless connectivity through various types of networks, including wireline networks and WLANs. Different types of multiple access techniques, such as the ones based on multicarrier CDMA and OFDM (orthogonal frequency division multiplexing) have been proposed. There is a need for functional integration of the multiple networks, and, with the evolution of IPv6 and QoS support for IP networks, an IP based interconnectivity is best suited. A QoS aware adaptive radio resource management technique based on multi-code multicarrier CDMA is discussed. We develop a novel radio access method and develop algorithms for allocating and controlling radio network resources so that system performance can be maximized and guaranteed QoS for multimedia services can be provided within the DiffServ environment.

A study of DiffServ based QoS issues in next generation mobile networks

To provide data rates of the order of hundreds of Mbps and multimedia services, standardization efforts for next generation (4G) systems are focusing on target technologies and seamless connectivity through various types of networks, including wireline networks and WLANs. Different types of multiple access techniques, such as the ones based on multicarrier CDMA and OFDM (orthogonal frequency division multiplexing) have been proposed. There is a need for functional integration of the multiple networks, and, with the evolution of IPv6 and QoS support for IP networks, an IP based interconnectivity is best suited. A QoS aware adaptive radio resource management technique based on multi-code multicarrier CDMA is discussed. We develop a novel radio access method and develop algorithms for allocating and controlling radio network resources so that system performance can be maximized and guaranteed QoS for multimedia services can be provided within the DiffServ environment.

Wavelet based multicarrier CDMA system

Emerging demands for high data rate services, high user capacity and low power consumption systems are the key driving forces behind the continued technology evolution in wireless communications. Multicarrier Modulation techniques support variety of services requiring different data rates and different QoS (quality of service) levels. Multicarrier CDMA is a wireless communication system that can be seen as a combination of direct sequence CDMA and Orthogonal Frequency Division Multiplexing techniques. The main benefits of this system are its robustness to inter symbol interference and multipath propagation in fading channels. This paper studies and simulates the Discrete Wavelet Transform based Multicarrier CDMA and compares it with the Discrete Fourier Transform based one using different number of sub carriers, and different modulation techniques. The results shows that the Wavelet based system outperforms the Fourier based one since it has lower bit error rate BER performance, lower peak to verage power ratio PAPR and higher user capacity.

Multi-code Multicarrier CDMA: Performance Analysis

A new multi-code multicarrier code division multiple access (MC-MC-CDMA) system is proposed and analyzed in afrequency selective fading channel. By allowing each user to transmit an M-ary code sequence, the proposed MC-MC-CDMA system can support various data rates as required by next generation standards without increasing the interference which is common in general multicarrier CDMA systems. The bit error rate of the system is analytically derived in frequency selective fading, with Gaussian noise and multiple access interference. The results show that the proposed MC-MC-CDMA system clearly outperforms both single-code multicarrier CDMA (MC-CDMA) and single-carrier multi-code CDMA in a fixed bandwidth allocation.This indicates that MC-MC-CDMA can be considered for next generation cellular systems.