Peter Moberg

Reducing Energy Consumption in LTE with Cell DTX

This paper discusses how energy consumption can be significantly reduced in mobile networks by introducing discontinuous transmission (DTX) on the base station side. By introducing DTX on the downlink, or cell DTX, we show that it is possible to achieve significant energy reductions in an LTE network. Cell DTX is most efficient when the traffic load is low in a cell but even when realistic traffic statistics are considered the gains are impressive. The technology potential for a metropolitan area is shown to be 90% reduced energy consumption compared to no use of cell DTX. The paper also discusses different drives for the increased focus on energy efficient network operation and also provides insights on the impact of cell DTX from a life cycle assessment perspective.

Performance and Cost Evaluation of Fixed Relay Nodes in Future Wide Area Cellular Networks

Future cellular networks are expected to provide significantly higher capacity than todays systems. This might require a denser access point deployment, with a potential increase in network deployment cost as a consequence. A promising way to reduce cost is a multi-hop deployment where wireless relay nodes (RN) are introduced to enhance capacity and coverage. In this paper, a deployment procedure for a static radio environment is considered, adding RNs incrementally as a complement to initially deployed macro base stations (BS). Different strategies of deploying BSs and RNs, providing equal service levels, are analyzed from a cost perspective. We develop a methodology that can determine and compare the most cost efficient deployment mixes of BSs and RNs. Further, we compare a deployment of macro BSs and relays with a deployment of macro BSs and micro BSs. Results show that relays are more cost efficient if the micro BS cost is between 10 and 15 % higher compared to the cost of an RN.

Cost Assessment and Optimization Methods for Multi-Node Radio Access Networks

The expected performance improvements of next-generation mobile radio access networks (RANs) can be achieved, e.g., by a flexible deployment of different types of radio access points (RAPs), such as intelligent relay nodes (RNs). To facilitate a cost-vs.-performance assessment of different deployment options, this paper presents a classification of different RAN cost components. Then, a method for deployment cost optimization is introduced which allows a comparison of the cost effectiveness of different RAN deployments by calculating optimum densities of different RAP types, based on a multi-dimensional iso-performance map. This method is first derived in theory and then demonstrated for two different deployment scenario examples.

WLC07-2: Simultaneous Routing and Resource Allocation in Multihop Wireless Networks using Optimization

Wireless multihop networks hope to provide increased total capacity and enhanced coverage at possibly low cost. In this paper, we are interested in the jointly optimal routing and power allocation, i.e. cross-layer design between the physical and the network layer. We formulate this as a convex mathematical programming problem, with objective function to minimize the total power, and propose a distributed solution method. Based on the theoretical results we implement a heuristic solution algorithm and study the performance on a set of test problems. We manage to establish convergence for the standard solution method and also for a more practically realistic model where the information passing between the nodes is limited.