抄録

Heterogeneous wireless systems, such as a combination of mobile broadband wireless access (MBWA) and wireless local area network (WLAN), are candidates to achieve large capacity in next generation mobile communication systems. For capacity expansion, small cells of multiple wireless networks are deployed densely in these systems. Many cells overlap. Therefore, users must discover many cells at once for cell selection. Consequently, radio resources are used intensively for cell selection. Cell selection errors occur in dense small cell environments. As described herein, a channel quality map construction scheme using multi-Global Navigation Satellite System (GNSS) signals for heterogeneous wireless networks is proposed. The scheme uses positioning information and the average of signal strength for cell selection. Using positioning information, users can select cells which have a better channel quality quickly and easily. The proposed scheme is considered to be useful to optimize data traffic offloading in the heterogeneous wireless network. The 50 % user throughput and system throughput of the proposed scheme by comparison with the conventional scheme which uses measured instantaneous signal strength was studied. Computer simulation results show that the proposed scheme can improve the 50 % user throughput by 68 % in comparison with the conventional scheme. In addition, the system throughput is enhanced by 10 % compared with the conventional scheme. Furthermore, based on measured data, the positioning accuracy with multi-GNSS signals is a realizable level for the channel quality map construction scheme. This report describes the developed channel quality map construction scheme prototype system.