Hybrid wireless-optical broadband access network (WOBAN) optimizes the cost and performance of an access network. A cost-effective way of increasing the capacity of the wireless part of a WOBAN is to assign multiple radios to the wireless nodes. An efficient channel assignment scheme is essential to reduce delay and contention in the wireless front-end of WOBAN. We study a channel assignment scheme that performs load balancing over the flows in WOBAN. We formulate this problem as an integer linear program (ILP) and solve it using a standard solver such as CPLEX. As expected, by assigning channels optimally, we lower the delay and balance the load across different channels.