WiMAX in Niedersachsen
Today broadband Internet access is regarded as an important and strategic factor for enterprises, private households and also for the medical and the educational sector. Unfortunately, there is still a digital divide between urban and rural areas regarding a basic broadband Internet access. This digital divide is mainly caused by economic constraints. The development and implementation of wired broadband networks, especially in rural areas, is very cost intensive and costs often cannot be amortized in an acceptable period of time. A possible and promising solution is the implementation of hybrid broadband access networks, a combination of wired and wireless broadband access technologies by one network carrier. Within the WiMAX pilot project in Lower Saxony, a wireless access broadband technology, based on the IEEE 802.16e standard will be analyzed for its capability to provide reliable and economically justifiable infrastructure in one rural area in the northern part of Germany. The WiMAX project is run by the L3S Research Center, Leibniz Universität Hannover, the Technische Universität Braunschweig, one regional network carrier and a technology vendor.
The main research and development aspects of this project are:
Analysis and development of wave propagation models for rural areas: Depending on the topography and other parameters the capacity of a wireless broadband technology can vary. The main targets of this project are the analysis and development of a wave propagation model for rural areas to predict the capacity of WiMAX by using a simulation tool.
Prediction of coverage and achievable throughput: Inspired by the challenge to predict the coverage and more importantly the achievable throughput of the WiMAX base station before it was actual built, the communication systems group focuses on the development and evaluation of a simulation tool to calculate the physical layer data rates based on channel information.
The goal of this research is to generate a map of the achievable data transfer rates in the downlink at each location in the desired area which needs to be covered by a base station, based on the received signal strength and the channel information that can be measured prior to installation. Such a simulation framework aims at planning the coverage more reliably, especially in rural areas, and therefore gives an indication whether a wireless communication technology can meet the needs of the network providers.
Cooperative diversity: Though WiMAX is a promising technology that offers high data rate over a relatively large area, it still suffers from some limitations issues. These issues include low SINR and also poor signal reception especially at cell edges. Cooperative diversity has been considered as a way to overcome these issues as it can increase performance and reliability. In this research, some sample nodes with poor reception are marked and measured. Our intention is to find a spot/node with better reception that can be acted as a cognitive relay or cooperative node for the other nodes. It is expected to improve coverage and also performance in terms of BER.
Capacity and performance analysis: Effective data throughput, packet loss, jitter, delay and other Quality of Service (QoS) parameters are essential for a high user acceptance. Within this project the capabilities of real WiMAX infrastructure will be analyzed and compared with the QoS requirements of different future Internet applications.
Network simulation: Within this project a network simulation model will be developed to provide a holistic analysis of wireless broadband access networks regarding the QoS requirements of future Internet applications. Simulation results will be compared with measurement results from the real WiMAX network infrastructure.
Economic requirements: Besides various technological aspects the main parameters to integrate a new technology into the market are economic ones. Taking this into account, within this project a full analysis of CAPEX and OPEX (invest and operation) will be done. Based on the results, it will be determined whether WiMAX is a feasible solution to provide broadband access in rural areas of Europe.