With the foreseeable explosive growth of small cell deployment, backhaul has become the next big challenge in the next generation wireless networks in terms of capacity and latency, especially for delay-sensitive services and network functionalities. Heterogeneous backhaul deployment using different wired and wireless technologies may be a potential solution to meet this challenge. Therefore, it is cardinal to evaluate and compare the performance characteristics of various backhaul technologies as a means to understand the effect of backhaul on the total network performance. In this paper, we propose relevant backhaul models and study the delay performance of promising technologies, including fiber, xDSL, millimeter wave (mmWave), and sub-6 GHz, which have different characteristics. Numerical results are presented to show the delay performance characteristics of different backhaul solutions.