We point out the unstable operation of reverse traffic management in the cdma2000 1xEV-DO system, and propose a new rate control scheme that controls the reverse traffic load more precisely. The proposed scheme is modeled as a multidimensional Markov process and compared with the conventional scheme. The analysis results show that the proposed rate control scheme has a lower overload probability and higher reverse link throughput than the conventional one.

In order to improve the forward link capacity of cdma2000 HRPD (High Rate Packet Data) or CDMA2000 1xEV-DO, it is significant to overcome multi-path interference. This paper focuses on FDE (Frequency Domain Equalization) with MMSE (Minimum Mean Square Error) criterion. On top of that, backward compatibility with HRPD should be maintained, in other words common channels such as the pilot channel should not be changed. Thus, the PN (Pseudo Noise) spread pilot block without CP (Cyclic Prefix) signals has to be dealt with for FDE. However, this will cause the conventional channel estimation accuracy to deteriorate. In order to improve the estimation accuracy of the conventional method, this paper presents a MRC (Maximal Ratio Combining) spectrum estimator, IPI (Inter-Path Interference) canceller, and path searcher. The results obtained from computer simulations reveal that the proposed method can improve the PER (Packet Error Rate) performance significantly. If compared with Rake combiner and TDE (Time Domain Equalization) with NLMS (Normalized Least Mean Square) scheme, the maximum data rates at a fixed PER of 1% can be increased by 5 to 8 times and 1.25 to 2.67 times, respectively.

The uplink performance of WCDMA with voice and World Wide Web (WWW) traffic over Dedicated Channel (DCH)/Common Packet Channel (CPCH) is investigated. The probability of voice packet dropping and average data packet delay are obtained by system level simulation. The system level simulation is conducted based on received Signal-to-Interference Ratio (SIR) with imperfect power control. In addition, we show that the performance of CPCH in terms of probability of data packet dropping is superior to that of DCH for transmitting WWW traffic. Furthermore, we obtain the supportable number of voice users when the target probability of voice packet dropping is set to be 10-2. The supportable number of data users is also found around knee area of average data packet delay.

Radio packet schedulers are currently being implemented in cdma2000 1x and 1xEV. cdma2000 1x stems from TIA/EIA-95 that was optimised to support circuit-based voice communications and is now extended to support high speed data transmission up to 153.6 kbps. 1xEV is primarily for wireless Internet access and can support up to maximally 2.4 Mbps. Compared with other 3G mobile systems that focus on voice services and guaranteed quality of the services, 1xEV exploits the delay-tolerant transmission of the packet data services so as to achieve spectral efficiency and reduce the cost of providing such services. Supporting multimedia transfer including real-time as well as delay-tolerant data transmission, however, is a must in designing packet schedulers for future mobile systems. In this letter, we address design issues of a packet scheduler by comparing two existing different schedulers: WQDS (Weighted Queuing Rate Scheduler) for cdma2000 1x and PFRS (Proportional Fairness Rate Scheduler) for 1xEV. Comparisons are made on the structure of schedulers as well as by numerical evaluations of performance.

The frequent and time-independent packet loss due to signal noise in the wireless network has been a major obstacle in providing a persistent end-to-end bandwidth in the integrated environment of wired and wireless networks. One approach to cope with this is to develop an efficient transport mechanism which appropriately adapts to the dynamics of the wireless part of the network so that the end-to-end throughput is maximised. The success of new transport mechanisms depends on the quality of information obtained, in particular, from the wireless network. This paper presents a novel mechanism to assess accurately the transmission quality of the wireless part of the integrated CDMA2000 1X networks using the NAK rate obtained from the underlying RLP protocol stack. The experiment results show that the proposed mechanism correctly measures the wireless transmission quality of the CDMA2000 1X network.

The future third generation mobile communications system, named IMT-2000, is expected to provide mobile users with voice, high-rate data and their combined multi-media services with the same QoS as in the fixed networks. As a radio access standard for the IMT-2000, W-CDMA and cdma2000 have been selected in Europe and North America, respectively. In this paper, we present an analytic model of the cdma2000 data mobile servicing a connected data service. In order to do this, we first model the traffic generated at mobile by a discrete-time Batch Markovian Arrival Process (D-BMAP). Next, we model the Radio Link Protocol (RLP) Queue in the cdma2000 MAC protocol by a D-BMAP/D/1 queueing system with batch service and setup times. Finally, we analyze this queueing system and get the performance measures such as the mean delay and the loss probability. Analytic results are compared with simulation ones for accuracy.