We consider the problem of uplink/downlink scheduling in a multichannel wireless access point network where channel states differ across channels as well as users, vary with time, and can be measured only infrequently. We demonstrate that, unlike infrequent measurement of queue lengths, infrequent measurement of channel states reduce the maximum attainable throughput.We then prove that in frequency division multiplexed systems, a dynamic scheduling policy that depends on both the channel rates (averaged over the measurement interval) and the queue lengths, is throughput optimal. We also generalize the scheduling policy to solve the joint power allocation and scheduling problem. In addition, we provide simulation studies that demonstrate the impact of the frequency of channel and queue state measurements on the average delay and attained throughput.