Opportunistic Scheduling of Machine Type Communications as Underlay to Cellular Networks Samad Ali, Nandana Rajatheva Centre for Wireless Communications, University of Oulu, Oulu, Finland samad.ali@oulu.fi,
[email protected].fi Abstract—In this paper we present a simple method to exploit number of devices trying to access the network, novel solutions the diversity of interference in heterogenous wireless communica- should be developed to increase the spectral efficiency of the tion systems with large number of machine-type-devices (MTD). wireless communication systems. We consider a system with a machine-type-aggregator (MTA) as underlay to cellular network with a multi antenna base In this paper, we focus on providing solutions for massive station (BS). Cellular users share uplink radio resources with number of MTDs. One of the methods of providing connec- MTDs. Handling the interference from MTDs on the BS is the tivity for MTC is by capillary networks [8], [9]. In capil- focus of this article. Our method takes advantage of received lary networks, MTC nodes transmit data to a machine-type- interference diversity on BS at each time on each resource block aggregator (MTA) and then MTA forwards collected data to and allocates the radio resources to the MTD with the minimum interference on the BS. In this method, BS does not need to take the cellular network. In this paper, we assume that MTC node the interference from MTD into account in the design of the to MTA communication link is an underlay link to cellular receive beamformer for uplink cellular user, hence, the degrees of communications.