The Third Generation Partnership Project's Long Term Evolution-Advanced is considering the use of relaying for cost-effective throughput enhancement and coverage extension. While analog repeaters have been used to enhance coverage in commercial cellular networks, the use of more sophisticated fixed relays is relatively new. The main challenge faced by relay deployments in cellular systems is overcoming the extra interference added by the presence of relays. Because most prior work on relaying does not consider interference, good relay strategies for cellular networks are not widely known. This paper analyzes the performance of several emerging half-duplex relay strategies in the context of interference- limited cellular systems: one-way relays, two-way relays, and shared relays. The performance benefits of each relay strategy as a function of location, sectoring, and frequency reuse is compared with local base station coordination. One-way relaying is shown to provide modest gains over single-hop cellular networks in some regimes. Shared relaying is shown to approach many of the gains of local base station coordination at reduced complexity, while two-way relaying further reduces complexity but only works well when the relay is very close to the mobile device. Frequency reuse of one, where each sector and cell reuses the same spectrum, is shown to have the highest network throughput. Simulations with realistic channel models provide performance comparisons that reveal the importance of interference mitigation in multihop cellular networks.