A method of transmitting packets by a mobile station in an OFDM system comprising the mobile station and a base station, wherein the mobile station comprises a processing unit, a queue for storing packets, and a network interface, the method comprising the steps of: making a bandwidth request to the base station, for each connection identifier of the mobile station for which there is a packet in the queue which is associated with the connection identifier; receiving a bandwidth allocation from the base station; determining if a size of the bandwidth allocation matches a size of a bandwidth required to transmit one or more delay-sensitive packets in the queue; transmitting with the network interface the most delay-sensitive packets in the bandwidth allocated by the base station if the size of the bandwidth allocation matches the size of the bandwidth required to transmit the one or more delay-sensitive packets using a modulation and coding scheme specified by the base station; in response to determining that the size of the bandwidth allocation does not match the size of the bandwidth required to transmit the one or more delay-sensitive packets, determining if the size of the bandwidth allocation is less than a size of a required bandwidth for any of the packets in the queue; fragmenting with the processing unit the most delay-sensitive packet to transmit a fragment of the most delay-sensitive packet with the network interface in the bandwidth allocated by the base station if the size of the bandwidth allocation is less than the size of the required bandwidth for any of the packets in the queue, using the modulation and coding scheme specified by the base station; using packing and/or fragmenting on packets by the processing unit to fit data into the allocated bandwidth, starting from the most delay-sensitive packets, to transmit with the network interface the most delay-sensitive packets in the bandwidth allocated by the base station, if the size of the bandwidth allocation is more than a required bandwidth for at least one of the packets in the queue, using the modulation and coding scheme specified by the base station, wherein packing is achieved when multiple service data units, SDUs, from the higher layer are packed into a single MAC protocol data unit, PDU. making a bandwidth request to the base station, for each connection identifier of the mobile station for which there is a packet in the queue which is associated with the connection identifier; receiving a bandwidth allocation from the base station; determining if a size of the bandwidth allocation matches a size of a bandwidth required to transmit one or more delay-sensitive packets in the queue; transmitting with the network interface the most delay-sensitive packets in the bandwidth allocated by the base station if the size of the bandwidth allocation matches the size of the bandwidth required to transmit the one or more delay-sensitive packets using a modulation and coding scheme specified by the base station; in response to determining that the size of the bandwidth allocation does not match the size of the bandwidth required to transmit the one or more delay-sensitive packets, determining if the size of the bandwidth allocation is less than a size of a required bandwidth for any of the packets in the queue; fragmenting with the processing unit the most delay-sensitive packet to transmit a fragment of the most delay-sensitive packet with the network interface in the bandwidth allocated by the base station if the size of the bandwidth allocation is less than the size of the required bandwidth for any of the packets in the queue, using the modulation and coding scheme specified by the base station; using packing and/or fragmenting on packets by the processing unit to fit data into the allocated bandwidth, starting from the most delay-sensitive packets, to transmit with the network interface the most delay-sensitive packets in the bandwidth allocated by the base station, if the size of the bandwidth allocation is more than a required bandwidth for at least one of the packets in the queue, using the modulation and coding scheme specified by the base station, wherein packing is achieved when multiple service data units, SDUs, from the higher layer are packed into a single MAC protocol data unit, PDU.