Abstract: A transmission control apparatus for improving PCT bi-directional transmission performance in an end node or gateway node of an asymmetric bandwidth pre-allocated subscriber network. The transmission control apparatus includes a TCP classification module for acquiring a TCP ACK packet to be transmitted over an uplink during bi-directional transmission; a band-width estimation/prediction module for estimating bandwidth of a downlink corresponding to the uplink at a time when the ACK packet is acquired, predicting following bandwidth of the downlink according to the estimated bandwidth, and calculating a optimal window size of the downlink such that the predicted bandwidth maintains residual bandwidth enough to allow transmission of an ACK packet over the downlink link compared with the maximum bandwidth allocated to the downlink; and a controller for inserting the calculated optimal window size as a reception window size included in the ACK packet and delivering the ACK packet to a destination node.

Abstract: A method and system for estimating an average bandwidth in a wired/wireless communication network with a time-varying rate are provided. In a TCP network, differences between inter-arrival times and sequence numbers of current and previous Acks are calculated. The estimated bandwidth of the previous Ack and a sample bandwidth of the current Ack are calculated. The inter-arrival time of the current Ack is compared with the inter-arrival time of the previous Ack. A first weight to be multiplied by the estimated bandwidth of the previous Ack and a second weight to be multiplied by the sample bandwidth of the current Ack, according to the comparison, are determined. The bandwidth of the current Ack is estimated by weighting the estimated bandwidth of the previous Ack with the first weight, and weighting the sample bandwidth of the current Ack with the second weight.