Communication apparatus, communication method and program

Abstract

A communication apparatus includes an error detection unit conducting error detection on N packet data units received in N transmission processes; a first transmission unit transmitting an affirmative response signal or a first retransmission request signal depending on a result of the error detection; a storage unit storing an affirmatively responding packet for forwarding to an upper layer; a second transmission unit, if affirmatively responding packets are not consecutive, determining whether a missing packet must be retransmitted and transmitting a second retransmission request signal; and a forwarding unit reordering the packet data units and forwarding the packets in the storage unit to the upper layer.

1 . A communication apparatus for receiving data in accordance with an N process SAW based hybrid ARQ method, comprising:
 an error detection unit conducting error detection on N packet data units received in N transmission processes;   a first transmission unit transmitting an affirmative response signal or a first retransmission request signal depending on a result of the error detection;   a storage unit storing an affirmatively responding packet for forwarding to an upper layer;   a second transmission unit, if affirmatively responding packets are not consecutive, determining whether a missing packet must be retransmitted and transmitting a second retransmission request signal; and   a forwarding unit reordering the packet data units and forwarding the packets in the storage unit to the upper layer.   
     
     
         2 . The communication apparatus as claimed in  claim 1 , wherein the second retransmission request signal is generated if a retransmission process for the missing packet is not being carried out or if an error is detected in the missing packet even after completion of the retransmission process for the missing packet. 
     
     
         3 . The communication apparatus as claimed in  claim 1 , wherein the order of packets is determined with identification numbers assigned to the respective packet data units. 
     
     
         4 . A method of receiving data in accordance with an N process SAW based hybrid ARQ method, comprising the steps of:
 conducting error detection on N packet data units received in N transmission processes;   transmitting an affirmative response signal or a first retransmission request signal depending on a result of the error detection;   storing an affirmatively responding packet for forwarding to an upper layer and determining order of the packets;   if the determined order is not consecutive, determining whether a missing packet must be retransmitted and transmitting a second retransmission request signal; and   reordering the packet data units and forwarding the packets in the storage unit to the upper layer.   
     
     
         5 . The method as claimed in  claim 4 , wherein the second retransmission request signal is generated if a retransmission process for the missing packet is not being carried out or if an error is detected in the missing packet even after completion of the retransmission process for the missing packet. 
     
     
         6 . A program causing a communication apparatus to receive data in accordance with an N process SAW based hybrid ARQ method, comprising the steps of:
 conducting error detection on N packet data units received in N transmission processes;   transmitting an affirmative response signal or a first retransmission request signal depending on a result of the error detection;   storing an affirmatively responding packet for forwarding to an upper layer and determining order of the packets;   if the determined order is not consecutive, determining whether a missing packet must be retransmitted and transmitting a second retransmission request signal; and   reordering the packet data units and forwarding the packets in the storage unit to the upper layer.   
     
     
         7 . The program as claimed in  claim 6 , wherein the second retransmission request signal is generated if a retransmission process for the missing packet is not being carried out or if an error is detected in the missing packet even after completion of the retransmission process for the missing packet.