Retransmission method with soft combining in a telecommunications system
First Claim
1. A data transmission method in a communications system, comprising the steps oftransmitting data packets from a transmitter to a receiver, using an automatic repeat request mechanism for retransmissions, said mechanism including combining initially transmitted and retransmitted versions of the data packet, sending, in association with each packet retransmission, outband signaling information which unambiguously indicates when the initial version of the data packet was transmitted, combining the retransmitted version of the data packet with at least the initial version of the data packet indicated by said outband signaling information at the receiver.
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Accused Products
Abstract
An automatic repeat request mechanism (such as Type II/III hybrid ARQ) which includes (soft or hard) combining of initially transmitted and retransmitted versions of a packet, is provided for retransmission of erroneous packets. According to the present invention, in association with each retransmission, there is outband signaling from a transmitter to a receiver that unambiguously indicates when, e.g. the exact time or physical location, the first transmission of the packet was carried out, so that it is possible to combine the retransmitted version with the previous version(s) of the packet. Soft combining requires that the initial packet and the retransmitted packet be identical. In an embodiment of the invention, in order to overcome this problem, the information that needs to be changed between the initial transmission and the retransmission(s) of a packet is sent outband with other outband signaling information. Thus, the retransmitted packet can be maintained unchanged and the requirement for identical packets in soft combining is met.
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Citations
36 Claims
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1. A data transmission method in a communications system, comprising the steps of
transmitting data packets from a transmitter to a receiver, using an automatic repeat request mechanism for retransmissions, said mechanism including combining initially transmitted and retransmitted versions of the data packet, sending, in association with each packet retransmission, outband signaling information which unambiguously indicates when the initial version of the data packet was transmitted, combining the retransmitted version of the data packet with at least the initial version of the data packet indicated by said outband signaling information at the receiver.
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14. A communications system, comprising
means for transmitting data packets from a transmitter to a receiver, an automatic repeat request mechanism for retransmissions, said mechanism including combining initially transmitted and retransmitted versions of the data packet, means for sending, in association with each packet retransmission, outband signaling information which unambiguously indicates when the initial version of the data packet was transmitted, means for combining the retransmitted version of the data packet with at least the initial version of the data packet indicated by said outband signaling information at the receiver.
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27. A transmitter unit in a communications system, comprising
means for transmitting data packets to a receiver, an automatic repeat request mechanism for retransmissions, means for sending, in association with each packet retransmission, outband signaling information which unambiguously indicates when the initial version of the data packet was transmitted, in order to enable the receiver to combine the retransmitted version of the data packet with at least the initial version of the data packet indicated by said outband signaling information at the receiver.
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32. A receiver unit in a communications system, comprising
means for receiving data packets from a transmitter, an automatic repeat request mechanism for retransmissions, said mechanism including combining initially transmitted and retransmitted versions of the data packet, means for receiving from the transmitter, in association with each packet retransmission, outband signaling information which unambiguously indicates when the initial version of the data packet was transmitted, means for combining the retransmitted version of the data packet with at least the initial version of the data packet indicated by said outband signaling information.
Specification