Relevance Based Power Saving Mechanism in a Multi-RAT User Equipment

摘要

In a mobile device or user equipment (UE) with multiple radio access technologies (RATs) an essential procedure to enable mobility across all RATs is to search for suitable cells in each supported RAT. The search procedure includes measurement of signal strength of the cells and receiving of network parameters, e.g., system information in LTE cell. To perform the search procedure it involves power consumptions by each of the RAT access stratum (RAT-AS) in a UE. In this paper, the authors propose a novel mechanism to selectively switch OFF less relevant access stratums of the dormant RATs. This paper defines a set of parameters for this purpose. These parameters are (1) user preference, (2) ratio of number of cells with Received Signal Strength Identifier (RSSI) above a defined threshold to the number of cells searched, (3) ratio of the number of cells searched to maximum number of cells that can be searched within a given power usage limit, (4) ratio of the number of cells suitable for mobility procedures to number of cells searched. Based on these parameters criteria are defined which are used to switch OFF irrelevant RATs in a UE. Simulation results show that for lesser number of cells searched (around 30% of maximum possible), the ratio of the number of cells searched to maximum number of cells that can be searched within a given power limit is the preferred parameter for switching OFF an irrelevant RAT-AS. Whereas for higher number of cells searched, user preference is the preferred option to switch OFF an irrelevant RAT-AS.