Hyung-Sub Kim

Resource allocation policy to avoid interference between cellular and D2D Links/ and D2D links in mobile networks

To cope with data communication explosion, the alternative, “D2D communication” which enables mobile devices to communicate each other without base station is studied. D2D providing service at a lower cost than cellular network is advantageous for user and also helpful when infra system is out of order by natural disaster. Even if D2D communication has a lot of benefits, that the D2D communication interferes cellular links as well as D2D link each other should be managed. This paper proposes a radio resource allocation policy for D2D link. Firstly, in frequency domain, by introducing D2D belt concept (the area where users cannot user frequency available only for D2D link) orthogonality between cellular links and D2D links is guaranteed in frequency domain. Secondly, by allocating un-overlapping subframe to D2D links, the interferences between D2D links can be eliminated.

Inter-cell Interference Coordination for Uplink Non-real-time Data in CDMA Systems

CDMA systems, interference is one of very important criteria to evaluate system performance. Interference is classified into inter-cell and intra-cell interference. While the intra-cell interference is generated by mobiles sharing the same base station, inter-cell interference is generated by the mobiles connected to different base stations. Many inter-cell interference mitigation schemes have been proposed to improve system performance. Most of them focus only on the downlink transmission. As for the downlink transmission, only one mobile is allowed to receive data from the base station at a moment except the broadcast service. However, as for the uplink transmission, multiple mobiles may have access to the base station simultaneously. The uplink inter-cell interference management is, therefore more difficult and important than the downlink. In this paper, we propose the inter-cell interference coordination scheme for uplink non-real-time transmission. This scheme shuts down a cell that injects lots of interference. The design of this scheme is based on the assumption that each base station applies the proportional fairness (PF) algorithm to the scheduling of uplink packets. The simulation results show that we can achieve improved system throughput by applying the proposed scheme.

Iterative power control to mitigate the interference between D2D and CDMA uplink services

To cope with data communication explosion, the alternative, “D2D communication” which enables mobile devices to communicate each other without base station is studied. Even though D2D communication has a lot of benefits (infra-less communication providing service at a lower cost and etc), the interference induced by D2D links is inevitable problem where D2D and cellular links share same radio channels. On the assumption that the D2D link uses the same uplink cellular channel in a CDMA system, this paper proposes a heuristic and iterative power control algorithm which approaches to the optimal solution maximizing the total uplink cellular throughput.