Group Based Multi-beams Subchannel Assignment for mmWave Internet of Things Networks

Wireless millimeter wave (mmWave) communication technology is promising to meet the low size, low weight and high data rate requirements in body area, Internet of Things (IoTs) networks. To combat the high path loss of mmWave channel, large scale array is employed to form several directional and narrow shape beams to serve multiple users. However, although the beams are narrow overlapping area may exist between multiple directional beams. This paper studies the resource allocation problem for a multi-beams communication system, which is proved to be NP-hard. This paper proposes a group based multi-beams subchannel assignment algorithm based on orthogonal frequency division multiple access (OFDMA). The beam spatial reuse gain is exploited for the groups of nodes deployed in difference coverage area of these beams, named as non-overlapped groups. And the multiple user diversity gain is exploited for the groups of nodes covered simultaneously by several beams, named as overlapped groups. Simulations results show that the throughput of the proposed algorithm outperforms the heuristic algorithm which only exploits the beam spatial reuse gain or the multiple user diversity gain.