A Traffic Aware Energy Saving Scheme for Multicarrier HSPA+

In the near future, an increase in cellular network density is expected to be one of the main enablers for the newly introduced challenging capacity goals. This development will lead to an increase in the network energy consumption. In this context, we propose an energy efficient dynamic scheme for HSDPA+ (High Speed Downlink Packet Access-Advanced) systems aggregating several carriers. In the proposed scheme the network adapts dynamically to the network traffic. The scheme evaluates whether node-B deactivation is feasible without compromising the user flow throughput. Furthermore, instead of progressive de-activation of carriers and/or node-B switch-off, we evaluate the approach where feasible combination of inter-site distance and number of carriers is searched to obtain best savings. The solution exploits the fact that re-activation of carriers might permit turning off the BSs earlier at relatively higher load than existing policies, which provides the highest energy saving. Remote electrical downtilt is also considered as a means to reduce the utilization of lower modulation and coding schemes (MCS) in the new extended cells. This approach promises significant energy savings when compared with existing policies not only for low traffic hours but also for medium load scenarios.