Flow rate control and resource allocation policy with security demands in OFDMA networks

OFDMA-based network performs well in maximizing the overall throughput, and meanwhile, problems with security requirements are focused to satisfy the increasing needs of confidential data transmissions. According to information theory, however, secure transmission undesirably antagonizes larger flow rate, thus a tradeoff is expected to balance these two matters. In this paper, we consider a downlink situation in OFDMA network, where all users request secure transmission from the base station yet the resources including power and subcarriers are limited such that an appropriate policy on resource allocation can play an instrumental role. Dynamic queueing and Lyapunov optimization are two highlights in this process. We utilize dynamic queueing so that merely instantaneous state of the network is enough, which is advantageous for easier implementations. On the other hand, by the means of Lyapunov optimization, we also prove our algorithm can obtain a performance of flow rate admission extremely close to the optimal. Applying this policy can reduce computational complexity significantly but still perform close to optimality.