Data communication method, system, and transmitter and receiver constituting the system
The present invention concerns a data communication method for communicating packetized data via an interface between a transmitter and a receiver, wherein communication relies on a layered communication protocol stack comprising at least two protocol layers of different hierarchy level, wherein at least data communication on a lower one of the layers adopts a retransmission scheme for data packets for which an acknowledgment of receipt was not received at the transmitter, the method comprising the steps of initializing the retransmission scheme of the lower one of the layers by setting a condition parameter, wherein fulfilling the condition defined by the condition parameter represents an indication as to how to control the retransmission scheme, wherein initializing comprises setting said condition parameter of the lower one of the layers according to information forwarded from the higher one of said layers to the lower one of said layers, transmitting packet data from the transmitter via the interface to the receiver according to the retransmission scheme of the lower one of the layers, detecting that the condition is fulfilled during transmitting, and controlling said retransmission scheme of the lower one of said layers in response to the detecting.
1. A data communication method
for communicating packetized data
via an interface
between a transmitter and a receiver, wherein communication relies on a layered communication protocol stack
comprising at least two protocol layers of different hierarchy level,
wherein at least data communication on a lower one of said layers
adopts a retransmission scheme for data packets for which an acknowledgment of receipt was not received at the transmitter,
the method comprising the steps of:
initializing the retransmission scheme of the lower one of said layers by setting a condition parameter, wherein fulfilling the condition defined by the condition parameter represents an indication as to how to control the retransmission scheme,
wherein
initializing comprises
setting said condition parameter of the lower one of said layers
according to information forwarded from said higher one of said layers to said lower one of said layers,
transmitting packet data from the transmitter via the interface to the receiver according to the retransmission scheme of said lower one of said layers,
detecting that said condition is fulfilled during transmitting, and
controlling said retransmission scheme of said lower one of said layers in response to said detecting.
2. A method according to claim 1 , wherein
said condition parameter comprises at least one of a lapse of a specified time, a function of the radio conditions, a function of the amount of data remaining to be sent/received to complete a segment of data transmission, a function of the amount of system load, a function of the sequence number of the packet received/sent, and a function of the number of application level packets remaining to be sent/received.
3. A method according to claim 1 , wherein said controlling comprises:
acknowledging receipt of the packet data; and
continuing transmission of the subsequent packet via the lower one of said layers.
4. A method according to claim 2 , wherein said controlling comprises:
determining to either abort or not the transmission via the lower one of said layers, and;
informing the higher one of said layers about a need for retransmission.
5. A data communication system,
comprising at least a transmitter and a receiver,
and being adapted to communicate packetized data via an interface between said transmitter and said receiver,
wherein communication relies on a layered
communication protocol stack
comprising at least two protocol layers of different hierarchy level,
wherein at least data communication on a lower one of said layers
adopts a retransmission scheme for data packets for which an acknowledgment of receipt was not received at the transmitter,
wherein
at the receiver side, the receiver is configured in terms of the retransmission scheme of the lower one of said layers by a set condition parameter,
wherein fulfilling the condition defined by the condition parameter represents an indication as to how to control the retransmission scheme, and
wherein said configured condition parameter of the lower one of said layers is set according to properties of said higher one of said layers, said transmitter is adapted to transmit packet data
via the interface to the receiver according to the retransmission scheme of said lower one of said layers,
said receiver comprises a detecting means adapted to detect that said condition is fulfilled during reception of transmitted packet data, and
said receiver comprises a control means adapted to control said retransmission scheme of said lower one of said layers in response to an output of said detecting means.
6. A system according to claim 5 , wherein
said condition parameter comprises at least one of a lapse of a specified time, a function of the radio conditions, a function of the amount of data remaining to be sent/received to complete a segment of data transmission, a function of the amount of system load, a function of the sequence number of the packet received/sent, and a function of the number of application level packets remaining to be sent/received.
7. A system according to claim 5 , wherein said control means is adapted to acknowledge receipt of the packet data to thereby continue transmission of the subsequent packet data via the lower one of said layers.
8. A system according to claim 5 , wherein said control means is adapted to determine to either abort or not the transmission via the lower one of said layers, and:
inform the higher one of said layers about a need for retransmission.
9. A receiver
for use with a data communication system adapted to communicate packetized data via an interface between a transmitter and said receiver,
wherein communication relies on a layered communication protocol stack
comprising at least two protocol layers of different hierarchy level,
wherein at least data communication on a lower
one of said layers
adopts a retransmission scheme for data packets for which an acknowledgment of receipt was not received at the transmitter,
comprising
configuration means adapted to configure the receiver in terms of the retransmission scheme of the lower one of said layers by a set condition parameter,
wherein fulfilling the condition defined by the condition parameter represents an indication as to how to control the retransmission scheme, and
wherein said configuration means is adapted to set said configured condition parameter of the lower one of said layers according to properties of said higher one of said layers,
receiving means adapted to receive packet data transmitted from said transmitter via the interface to the receiver according to the retransmission scheme of said lower one of said layers, and
detecting means adapted to detect that said condition is fulfilled during reception of transmitted packet data, and
control means adapted to control said retransmission scheme of said lower one of said layers in response to an output of said detecting means.
10. A receiver according to claim 9 , wherein
said condition parameter comprises at least one of a lapse of a specified time, a function of the radio conditions, a function of the amount of data remaining to be sent/received to complete a segment of data transmission, a function of the amount of system load, a function of the sequence number of the packet received/sent, and a function of the number of application level packets remaining to be sent/received.
11. A receiver according to claim 9 , wherein said control means is adapted to acknowledge receipt of the packet data to the transmitter to thereby continue transmission of the subsequent packet data via the lower one of said layers.
12. A receiver according to claim 9 , wherein said control means is adapted to determine to either abort or not the transmission via the lower one of said layers, and;
inform the higher one of said layers about a need for retransmission.
13. A transmitter
for use with a data communication system adapted to communicate packetized data via an interface between said transmitter and a receiver,
wherein communication relies on a layered communication protocol stack comprising at least two protocol layers of different hierarchy level,
wherein at least data communication on a lower
one of said layers
adopts a retransmission scheme for data packets for which an acknowledgment of receipt was not received at the transmitter,
comprising
receiving means adapted to receive a feedback from external, and
control means adapted to control said retransmission scheme of said lower one of said layers in response to said received feedback.
14. A transmitter according to claim 13 , wherein
said control means is adapted to
continue transmission of the subsequent packet data via the lower one of said layers using said retransmission scheme, if the received feedback was a positive acknowledgment.
15. A transmitter according to claim 13 , wherein
said control means is adapted to
abort transmission via the lower one of said layers, and perform retransmission on the higher one of said layers, if the received feedback indicates that the retransmission scheme on the lower layer is to be stopped.
16. A method according to claim 2 , wherein said controlling comprises stopping additional duplicate acknowledgments from reaching the application.
17. A system according to claim 6 , wherein said control means is adapted to stop additional duplicate acknowledgments from reaching the application.
18. A receiver according to claim 9 , wherein said control means is adapted to stop additional duplicate acknowledgments from reaching the application.
19. A transmitter according to claim 13 , wherein
said control means is adapted to stop additional duplicate acknowledgments from reaching the application.