Effective SNR Based Handoff Scheme in Heterogeneous Cellular Environments

In cellular systems, a handoff process is defined to transfer an active call of an MS from one cell to another in order to provide a seamless service to this MS. Generally, a handoff decision is made based on received signal strength (RSS) values from the current base station (BS) and neighboring BSs. In the traditional mobile communication systems, measured RSS directly indicates the quality of the communication link because the same transmission/reception technologies are utilized for all devices. However, emerging cellular systems are defined to utilize various transmission/reception technologies, e.g., Multiple-Input Multiple-Output (MIMO), and different BSs and MSs might be capable of different technologies. Because RSSs do not indicate the quality of the link directly in such cases, we here propose to use a new metric, called effective SNR for handoff decision and show that the proposed scheme significantly improves the system performance when heterogeneous types of devices co-exist in the network.