Candidate: Yigit Ozcan
Title: How Useful is Full Duplex in Cellular Networks? The Impact of Interference and Traffic Asymmetry in a Multi-Cell OFDMA Network
Date: June 13, 2019
Time: 10:00 AM
Place: EIT 3142
Supervisor(s): Rosenberg, Catherine
Abstract:
We consider cellular networks where full-duplex communications (FDC) are enabled at the base stations. The coexistence of uplink and downlink transmissions in co-channel cells creates new sources of interference that should be taken into account when studying the performance of FDC. When doing so, traffic asymmetry (TA), i.e., the fact that the downlink traffic is much larger than uplink, should also be considered. We investigate the performance gain that an FDC-enabled multi-cell OFDMA network has over a time division duplex (TDD) system considering all sources of interference and TA. For that, we formulate two system-wide scheduling problems (FDC and TDD), which are large sized MINLP problems. To tackle this problem, using two non-trivial transformations, we obtain more tractable signomial programming problems and solve them to quasi-optimality using an iterative algorithm, in which we convert them into geometric programming problems in each iteration. We then analyze the impact of each source of interference as well as of TA. We show that ignoring TA biases the results in favor of FDC. Our conclusion is that, FDC cannot double the performance of cellular networks for realistic interference models and a realistic value of TA. The gain gets higher in the case of i) equal amount of uplink and downlink traffic, ii) rural networks, iii) heterogeneous networks, or iv) crowded networks.