Wideband Code Division Multiple Access Uplink Research Articles

Optimal implementation of novel WCDMA uplink outer loop power control algorithm

Wideband code division multiple access (WCDMA) uplink outer loop power control has been responsible for changing the signal to interference ratio (SIR) target value according to the SIR target control algorithms. Thus maintains the desired block error rate (BLER) for voice connections and transmission to target error rate (TTE) for data connections. During a call, the SIR target varies between implemented lower (sirMin) and upper boundaries (sirMax), which are fixed values on radio network control station (RNC). As possible solution for WCDMA uplink overload problems, a novel uplink outer loop power control algorithm with dynamic change of sirMax has been proposed. In this paper optimal implementation for dynamic change of sirMax has been investigated. Performance management statistic and general performance event handling (GPEH) data, for current uplink received signal strength indicator (UL RSSI) and required SIR target, have been obtained. Based on analysis from obtained data optimal implementation for dynamic change of sirMax has been proposed.

A New Technique for Capacity Enhancement in WCDMA Uplink with Synchronization

Cellular phones have experienced an exponential growth worldwide over the last decade with more than one billion cell phone users projected in the near future. On the other hand, service providers must support new technology and infrastructure in order to fulfill their customers' requirements. These requirements include the capacity of network. The large expectances created for Wide Band Code Division Multiple Access (WCDMA) are based on its flexibility for multimedia capabilities and the high capacity it will provide. However, the demanded traffic grows rapidly, and new capacity enhancements are required in order to satisfy the future needs. Uplink synchronization can be a method to reduce the multiple access interference (MAI) by exploiting the uplink orthogonality and thereby increase the capacity of WCDMA systems. In this paper, the performance of uplink synchronous WCDMA has been assessed in terms of the capacity gain relative to an equivalent asynchronous system. The capacity gain has been evaluated theoretically and by means of MATLAB simulations for scenarios with different orthogonality factors. Orthogonality of codes is directly dependent on synchronization which in turn increases the capacity gain. In this study, it is proposed that synchronization plays an important role in enhancing the capacity gain of uplink WCDMA system. Also, an alternative solution is proposed to increase the capacity in the uplink of a synchronized WCDMA system by introducing variable modulation.

Content aware optimization for video delivery over WCDMA

Abstract A content-aware networking framework for transmitting video on the uplink of a Wideband Code Division Multiple Access (WCDMA) cellular network is studied in this article. We consider a multi-user scenario and exploit the underlying structure of the video content to optimally schedule frames in order to minimize the total distortion of video quality across all users. In particular, we propose a novel Content-Aware Distortion Fair (CADF) scheme that determines, between multiple flows, the best set of frames to schedule using optimal transmit power, while meeting interference and delay constraints. The optimization problem is considered on the time scale of a single Group of Pictures, and is formulated as a restricted Multiple Knapsack Problem. A key contribution of this study is evaluating the CADF scheme on a Qualcomm 3G emulator, called “High data rate System Emulator 2” (HSE 2), and conducting rate control experiments with different types of emulated channel conditions. Our experimental results show that the CADF scheme significantly reduces video distortion, compared to the existing Foschini-Miljanic closed-loop distributed power control algorithm implemented on the WCDMA uplink. In the Appendix section, we also use the emulator to analyze the Traffic-to-Pilot resource allocation algorithm implemented on the reverse link of Evolution-Data Optimized (EV-DO) Revision-A by profiling over different traffic classes.

Characterisation of wideband code division multiple access uplink transmit power for typical mobile usage patterns

With the ever-increasing demand for higher data rates and longer talk times, designing low-power RF front ends in wideband code division multiple access (WCDMA) mobile handsets is an important task. However, the power efficiency of current WCDMA RF front ends, particularly power amplifiers, is very low over the range of typical output power levels. Thus, to improve the RF characteristics, it is important to understand typical output power requirements for WCDMA handsets in practical mobile usage conditions. In this study, the authors present a characterisation and analysis of WCDMA uplink power or handset transmit power for typical mobile usage patterns by location. Unlike previous studies, in this experimental study the authors take measurements using a real WCDMA phone over a commercial universal mobile telecommunications systems network while simulating practical mobile user behaviour. Specifically, the distribution and statistics of WCDMA uplink transmit power at various locations are investigated. Similar locations are then grouped to form four practical mobile usage scenarios, and their frequency histograms are analysed. Further, in each scenario the authors examine the dependency of uplink transmit power on several key factors (i.e. radio coverage, handset position and network loading) and the statistical properties of the transmit power variation.

WCDMA Uplink Interference Assessment from Multiple High Altitude Platform Configurations

We investigate the possibility of multiple high altitude platform (HAP) coverage of a common cell area using a wideband code division multiple access (WCDMA) system. In particular, we study the uplink system performance of the system. The results show that depending on the traffic demand and the type of service used, there is a possibility of deploying 3–6 HAPs covering the same cell area. The results also show the effect of cell radius on performance and the position of the multiple HAP base stations which give the worst performance.

W-CDMA uplink capacity and interference statistics of cigar-shaped microcells in over-ground train service with imperfect power control and finite transmitted power

The capacity and the interference statistics of the sectors of the shaped Wideband Code Division Multiple Access (W-CDMA) microcells serving over-ground trains are studied. A model of five microcells is used to analyze the uplink. The capacity and the interference statistics of the microcell are studied for different antenna sidelobe levels and different sector ranges. In the study, imperfect power control and limited transmitted power are assumed. The effect of the power assigned to the uplink pilot is taken into account. It is shown that, the sector capacity depends on the train's position. The uplink sector capacity limits (upper and lower) are presented. The lower capacity limit is given as a function of the sector range and the sidelobe level of the directive antenna used in each sector.

QoS-Aware Distributed Resource Management for a WCDMA Uplink

In this paper, a hybrid resource management system for the uplink in Universal Mobile Telecommunications System wideband code-division multiple access (WCDMA) with components in the Node-B and user equipment (UE) has been proposed. A rate scheduler in the client focuses on average packet delays as a means of abstracting application-specific requirements from the rest of the resource management scheme. It controls uplink transmission through variable spreading gain to optimize resource usage while meeting target delays. Service change requests from the distributed rate schedulers are collectively processed through interservice and intraservice priority queuing in a manner that is shown to exhibit fairness in allocation of resources when cumulative load exceeds system capacity. The performance of the proposed algorithm is explored through discrete-event simulations for three classes of traffic, namely voice, video, and data, over the WCDMA uplink in the presence of short-term Rayleigh fading, automatic repeat request, forward error correction, target transmission delays to meet the respective quality of service, and frame error rate targets in a "multicell" environment. The authors analyze two alternatives for distributed resource management with the UE or Node-B in control of rate scheduling and observe the fairness in resource allocation of both systems. Priority of speech, video, and data traffic is respected and reflected in 95th percentile transmission delays for heavily loaded systems