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US 8,477,682 B2Granted
Base station, terminal and wireless communication system
AssigneeHitachi, Ltd.
InventorsKeisuke Takeuchi, Rintaro Katayama, Tomonori Yamamoto, Koki Uwano
Life of this patent
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Abstract
Conventionally, different HARQ processes 801 and 802 (subframes T1 and T2) transmit data packets B and D, respectively. One data packet corresponds to one process and is retransmitted as necessary one by one on a process basis, degrading the usage efficiency of frequency and time resources. To solve this problem, downlink data packets B and D, when needed to be retransmitted, are spatially multiplexed in the different HARQ processes 801 and 802. The data packets are simultaneously retransmitted to the same terminal as process 805 (subframe T3).
Claims15
A base station that multiplexes and retransmits a plurality of independently retransmitted downlink data packets to an identical terminal and transmits one or more pieces of downlink control information for decoding the retransmitted downlink data packets to the same terminal,
- (1) wherein the base station, at subframe T1 in process P1, transmits data packet A as a first data packet using one of a first layer and a first channel and data packet B as a second data packet using one of a second layer and a second channel,
- provides downlink control information with process ID P1 as an identification number of a process associated with a relevant data packet, decoding information for a first data packet as decoding information applied to data packet A, and decoding information for a second data packet as decoding information applied to data packet B, and
- transmits one set of downlink control information containing information needed for decoding data packets A and B at the subframe T1;
- (2) wherein the base station, at subframe T2 different from subframe T1, transmits data packet C as a first data packet using one of a first layer and a first channel and data packet D as a second data packet using one of a second layer and a second channel,
- provides downlink control information with process ID P2, decoding information for a first data packet as decoding information applied to data packet C, and decoding information for a second data packet as decoding information applied to data packet D, and
- transmits one set of downlink control information containing information needed for decoding data packets C and D at the subframe T2;
- and
- (3) wherein, when one of data packets A and B is NAK'ed and one of data packets C and D is NAK'ed according to ACK/NAK indication received from the terminal, the base station retransmits NAK'ed data packets at subframe T3 to the terminal,
- selects one of a layer and a channel used for data packet re-transmission in process P1, assigns re-transmission to NDI for one of a layer number corresponding to the data packet and a packet number as identification information indicating one of initial transmission and re-transmission of the data packet, supplies decoding information applied to a data packet to be transmitted, assigns the value indicating initial transmission to NDI for one of the other layer number and packet number, and supplies decoding information and a dummy value to generate first downlink control information,
- defines one of a layer and a channel not selected for data packet re-transmission in process P1 as a layer used for data packet re-transmission in process P2, assigns the value indicating re-transmission to NDI for one of a layer number and a packet number corresponding to the data packet, supplies decoding information applied to a data packet to be transmitted, assigns the value indicating initial transmission to NDI for one of the other layer number and packet number, and supplies decoding information and a dummy value to generate second downlink control information, and
- retransmits the first downlink control information and the second downlink control information to the terminal at the subframe T3, each downlink control information containing information needed for decoding a data packet to be retransmitted.
8 more elements
A terminal that receives a re-transmission signal of a plurality of independently retransmitted and multiplexed downlink data packets from an identical base station and receives a plurality of control signals for decoding the downlink data packets from the same base station,
- (1) wherein the base station, at subframe T1 in process P1, transmits data packet A as a first data packet using one of a first layer and a first channel and data packet B as a second data packet using one of a second layer and a second channel to the terminal,
- provides downlink control information with process ID P1 as an identification number of a process associated with a relevant data packet, NDI representing one of initial transmission and re-transmission for a first data packet which has the value indicating initial transmission, decoding information for a first data packet as decoding information applied to data packet A, NDI for a second data packet which has the value indicating initial transmission, and decoding information for a second data packet as decoding information applied to data packet B, and
- transmits one set of downlink control information containing information needed for decoding data packets A and B at the subframe T1 to the terminal;
- (2) wherein the base station, at subframe T2 different from subframe T1, transmits data packet C as a first data packet using one of a first layer and a first channel and data packet D as a second data packet using one of a second layer and a second channel to the terminal,
- provides downlink control information with process ID P2, NDI for a first data packet which has the value indicating initial transmission, decoding information for a first data packet as decoding information applied to data packet C, NDI for a second data packet which has that value indicating initial transmission, and decoding information for a second data packet as decoding information applied to data packet D, and
- transmits one set of downlink control information containing information needed for decoding data packets C and D at the subframe T2 to the terminal;
- and
- (3) wherein, when one of data packets A and B is NAK'ed and one of data packets C and D is NAK'ed according to ACK/NAK indication received from the terminal, the base station retransmits NAK'ed data packets at subframe T3 to the terminal,
- selects one of a layer and a channel used for data packet re-transmission in process P1, assigns the value indicating re-transmission to NDI for one of a layer number corresponding to the data packet and a packet number as identification information indicating one of initial transmission and re-transmission of the data packet, supplies decoding information applied to a data packet to be transmitted, and assigns the value indicating initial transmission to NDI for one of the other layer number and packet number to generate first downlink control information,
- defines one of a layer and a channel not selected for data packet re-transmission in process P1 as a layer used for data packet re-transmission in process P2, assigns the value indicating re-transmission to NDI for one of a layer number and a packet number corresponding to the data packet, supplies decoding information applied to a data packet to be transmitted, and assigns the value indicating initial transmission to NDI for the other packet number to generate second downlink control information, and
- retransmits the first downlink control information and the second downlink control information to the terminal at the subframe T3, each downlink control information containing information needed for decoding a data packet to be retransmitted;
- (4) wherein, when receiving the two pieces of downlink control information at subframe T3 in such cases as described above, the terminal
- enables one of two bits of ACK/NAK indication correspondingly to one of ACK and NAK for a re-transmission packet decoded with reference to received downlink control information transmitted from a downlink control channel having a smaller downlink control channel number,
- enables the other one of two bits of ACK/NAK indication correspondingly to one of ACK and NAK for a re-transmission packet decoded with reference to received downlink control information transmitted from the other downlink control channel, and
- transmits one set of ACK/NAK indication indicating a result of decoding two data packets at subframe T3′.
12 more elements
The base station that multiplexes and retransmits a plurality of independently retransmitted downlink data packets to an identical terminal and transmits one or more pieces of downlink control information for decoding the retransmitted downlink data packets to the same terminal,
- (1) wherein the base station, at subframe T1 in process P1, transmits data packet A as a first data packet using one of a first layer and a first channel and data packet B as a second data packet using one of a second layer and a second channel to the terminal,
- provides downlink control information with process ID P1 as an identification number of a process associated with a relevant data packet, none for Swap representing correspondence between a set of first and second data packets and a set of first and second layers, NDI representing one of initial transmission and re-transmission for a first data packet which has the value indicating initial transmission, decoding information for a first data packet as decoding information applied to data packet A, NDI for a second data packet which has the value indicating initial transmission, and decoding information for a second data packet as decoding information applied to data packet B, and
- transmits one set of downlink control information containing information needed for decoding data packets A and B at the subframe T1 to the terminal;
- (2) wherein the base station, at subframe T2 different from subframe T1, transmits data packet C as a first data packet using one of a first layer and a first channel and data packet D as a second data packet using one of a second layer and a second channel to the terminal,
- provides downlink control information with process ID P2, NDI for a first data packet which has the value indicating initial transmission, decoding information for a first data packet as decoding information applied to data packet C, NDI for a second data packet which has the value indicating initial transmission, and decoding information for a second data packet as decoding information applied to data packet D, and
- transmits one set of downlink control information containing information needed for decoding data packets C and D at the subframe T2 to the terminal;
- and
- (3) wherein, when one of data packets A and B is NAK'ed and one of data packets C and D is NAK'ed according to ACK/NAK indication received from the terminal, the base station retransmits NAK'ed data packets at subframe T3 to the terminal using layers for transmission at subframes T1 and T2,
- selects one of a layer and a channel used for retransmitting a data packet in a first re-transmission process, assigns the value indicating re-transmission to NDI for a packet number corresponding to the data packet, supplies decoding information applied to a data packet to be transmitted,
- defines one of a layer and a channel not selected for data packet re-transmission in a first re-transmission process as one of a layer and a channel used for data packet re-transmission in a second re-transmission process, assigns the value indicating re-transmission to NDI for a packet number corresponding to the data packet, supplies decoding information applied to a data packet to be transmitted to generate one set of downlink control information, and
- retransmits one set of downlink control information to the terminal at the subframe T3, the downlink control information being needed for decoding each data packet to be retransmitted.
8 more elements
A terminal that receives a re-transmission signal of a plurality of independently retransmitted and multiplexed downlink data packets from an identical base station and receives a plurality of control signals for decoding the downlink data packets from the same base station,
- (1) wherein the base station, at subframe T1 in process P1, transmits data packet A as a first data packet using one of a first layer and a first channel and data packet B as a second data packet using one of a second layer and a second channel to the terminal, and
- transmits one set of downlink control information containing information needed for decoding data packets A and B at the subframe T1 to the terminal;
- (2) wherein the base station, at subframe T2 different from subframe T1, transmits data packet C as a first data packet using one of a first layer and a first channel and data packet D as a second data packet using one of a second layer and a second channel to the terminal,
- transmits one set of downlink control information containing information needed for decoding data packets C and D at the subframe T2 to the terminal;
- and
- (3) wherein, when one of data packets A and B is NAK'ed and one of data packets C and D is NAK'ed according to ACK/NAK indication received from the terminal, the base station retransmits NAK'ed data packets at subframe T3 to the terminal using layers for transmission at subframes T1 and T2,
- selects one of a layer and a channel used for retransmitting a data packet in a first re-transmission process, assigns the value indicating re-transmission to NDI for a packet number corresponding to the data packet, supplies decoding information applied to a data packet to be transmitted,
- defines one of a layer and a channel not selected for data packet re-transmission in a first re-transmission process as one of a layer and a channel used for data packet re-transmission in a second re-transmission process, assigns the value indicating re-transmission to NDI for a packet number corresponding to the data packet, supplies decoding information applied to a data packet to be transmitted to generate one set of downlink control information, and
- retransmits one set of downlink control information to the terminal at the subframe T3, the downlink control information being needed for decoding each data packet to be retransmitted;
- and
- (4) wherein, as a response to the downlink control information, the terminal enables a bit of ACK/NAK indication representing information about a first data packet in accordance with a result of decoding the first data packet, enables a bit of ACK/NAK indication representing information about a second data packet in accordance with a result of decoding the second data packet, and transmits one set of ACK/NAK indication to the base station using an uplink control channel.
8 more elements
Dependencies are inferred from the claim text.