Sidelink Grouping Method For Multicasting D2d Signaling Messages With Considerations Of Sidelink Transmission Power

The fifth generation mobile communication network will use a high frequency band for a wide bandwidth. However, since the high frequency band also involves high propagation loss and blockage, it is difficult to avoid coverage holes in a communication area. We are studying device-to-device (D2D) relay to fill these coverage holes. This is used where mobile terminals (MTs) in the coverage holes relay user traffic to the other MTs connected to a base station by a sidelink (SL), which is a link between MTs of D2D relay. To use a D2D relay, unicast signaling messages from the base station are needed to control the SL. When the number of SLs increases, the number of signaling messages increases proportionately. To reduce the signaling messages for SLs, we proposed a method of grouping MTs with SLs and multicasting signaling messages per group. However, since the proposed method assigns the same SL resource to a group, a certain distance between MTs is required to avoid interference between SLs. This means that the proposed method cannot be applied to crowded areas such as a stadium. To deal with this, we propose a new grouping method based on the SL transmission power. By conducting simulation evaluations, we show that our new proposed method can reduce the required number of control channel resources by 55% compared to the conventional method.