中文摘要：

异构无线网络环境下，无线终端可以采用多种接人技术（UMTS、LTE、WLAN等）进行通信．针对异构无线网络中带宽资源受限的问题，提出了一种基于带宽资源分配的网络选择策略．该策略首先以用户的信息传输速率作为目标函数，以带宽资源限制作为约束条件，采用凸优化理论得到最大化的信息传输速率，然后根据获得最大化信息传输速率所需的带宽资源和接入网络可提供的带宽资源，将用户分配到最合适的网络中，可以避免盲目接入造成的资源浪费．与已有的网络选择策略不同，提出的策略以带宽受限情况下最大化整体网络的信息传输速率和带宽利用率为目标．理论分析和仿真实验证明该文提出的网络选择策略可以获得较高的网络吞吐量和资源利用率．

英文摘要：

In heterogeneous wireless networks, a mobile terminal can transmit over multiple radio access technologies, such as UMTS, LTE and WLAN. A new network selection strategy based on bandwidth resource allocation is proposed to manage the problem caused by the limited bandwidth resource. The transmission rate is formulated as an object function with the constraint of bandwidth resource. An optimal rate solution is obtained by applying the convex theory. Then the user accesses the proper network according to both the demand for bandwidth resource and the available bandwidth resource of network which can avoid resource wasting. Compared with the previous network selection strategies, the proposed strategy focuses on maximizing the total transmission rate and the bandwidth utilization with the bandwidth resource constraint. Both the mathematical analysis and simulations show that the proposed network selection strategy can obtain higher throughput and resource utilization.