WIRELESS BASE STATION DEVICE USING COLLABORATIVE HARQ COMMUNICATION SYSTEM, WIRELESS TERMINAL DEVICE, WIRELESS COMMUNICATION SYSTEM, AND WIRELESS COMMUNICATION METHOD
In a transmission device on a serving eNB side, a first packet transmission unit performs an operation of transmitting a retransmission data packet. On the other hand, in a transmission device on a collaborative eNB side, a second packet transmission unit performs an operation of transmitting a new data packet corresponding to information transferred from the serving eNB by the packet transfer unit. The control information about a communication to a UE by the serving eNB and the collaborative eNB is communicated by using only a PUCCH from the UE to the serving eNB and a PDCCH from the serving eNB to the UE. The serving eNB and the collaborative eNB perform communications of a new data packet and communication control information etc. through an X2 interface.
1 . A wireless communication system in which a first wireless base station device and a second wireless base station device perform a collaborative transmission process for realizing the process to allow the wireless terminal device not to discard a packet on which decoding has failed but to combine the packet with a retransmitted packet and decode a resultant packet while controlling the retransmission of the packet according to transmission status information returned from the wireless terminal device, comprising:
the first wireless base station including a first processor; and
the second wireless base station including a second processor;
wherein
the first processor is configured to
transmit as a first packet a new data packet or a retransmission data packet corresponding to a retransmit request from the first wireless base station device to the wireless terminal device when the retransmit request is issued to the collaborative transmission process by the wireless terminal device; and to
transfer information about a second packet different from the first packet between the new data packet and the retransmission data packet from the first wireless base station device to the second wireless base station device; and
the second processor is configured to
transmit the second packet according to information transferred from the first base station in synchronization with a transmission process of the first packet from the second wireless base station device to the wireless terminal device when the retransmit request is issued.
2 . The wireless communication system according to claim 1 , wherein:
each of the first wireless base station device and the second wireless base station device has a memory; and
the first wireless base station device holds information about a packet on which a collaborative transmission process is performed for the wireless terminal device in the memory of the first wireless base station device; and
the second wireless base station device does not hold the information about a packet on which a collaborative transmission process is performed for the wireless terminal device in the memory of the second wireless base station device.
3 . The wireless communication system according to claim 1 , wherein
the first packet is the retransmission data packet, and the second packet is the new data packet.
4 . The wireless communication system according to claim 3 , wherein
the first processor is configured to read information about the retransmission data packet from the memory of the first wireless base station device, and to transfer the information to the second wireless base station device.
5 . The wireless communication system according to claim 1 , wherein
the first processor is configured to communicate between the first wireless base station device and the wireless terminal device control information about a communication to the wireless terminal device by the first wireless base station device and control information about a communication to the wireless terminal device by the second wireless base station device.
6 . The wireless communication system according to claim 5 , wherein
the first processor is configured to perform:
a transmission of the control information from the first wireless base station device to the wireless terminal device through a physical downlink control channel; and
a reception of the control information from the wireless terminal device to the first wireless base station device through a physical uplink control channel.
7 . The wireless communication system according to claim 6 , wherein
the physical uplink control channel includes at least individual channel quality indication information for each of the first wireless base station device and the second wireless base station device, and precoding matrix indication information and rank indication information common to the first wireless base station device and the second wireless base station device.
8 . The wireless communication system according to claim 6 , wherein
the physical downlink control channel includes at least individual modulation and coding scheme information and individual precoding information for each of the first wireless base station device and the second wireless base station device.
9 . The wireless communication system according to claim 1 , wherein
the control information from the wireless terminal device to the first wireless base station device includes transmission status information indicating a reception result of a packet from the first wireless base station device and a reception result of a packet from the second wireless base station device, respectively.
10 . The wireless communication system according to claim 1 , wherein
the first processor is configured to transfer the communication control information relating to the second wireless base station device for communication from the first wireless base station device to the wireless terminal device and information relating to a transmission timing of the second packet by the second wireless base station device.
11 . The wireless communication system according to claim 1 , wherein
the first processor is configured to control centrally at least assignment of the wireless terminal device, assignment of communication resources, and control of transmission timing relating to the collaborative transmission process.
12 . A wireless terminal device which performs a communication in a wireless communication system according to claim 1 , comprising: a third processor;
wherein
the third processor is configured to
perform a receiving process on the retransmission data packet when the retransmit request is issued; and to
perform, when the third processor successfully performs a receiving process on the retransmission data packet, a successive interference cancellation process on a received signal received by the wireless terminal device through a retransmission data packet on which the receiving process has been successfully performed, and perform the receiving process on the new data packet according to a resultant received signal.
13 . The wireless terminal device according to claim 12 , wherein
the third processor is configured to determine whether or not the collaborative transmission process is to be performed and to determine the first wireless base station device and the second wireless base station device performing the process when the execution of the collaborative transmission process is determined.
14 . The wireless terminal device according to claim 12 , wherein
the third processor is configured to make the determination according to information about reception power for a reference signal to be received from each wireless base station device currently in communication.
15 . The base station device which performs a communication in the wireless communication system according to claim 1 , comprising a processor;
wherein
the processor is configured to
transmit to the wireless terminal device as a first packet the new data packet or a retransmission data packet corresponding to a retransmit request when the base station device operates as the first wireless base station device and when the retransmit request to the collaborative transmission process is issued in the wireless terminal device;
transfer information relating to a second packet different from the first packet between the new data packet and the retransmission data packet to the second wireless base station device when the base station device operates as the first wireless base station device, and when the retransmit request is issued; and to
transmit the second packet according to information transferred from the first wireless base station device to the wireless terminal device in synchronization with the first packet by the first wireless base station device when the base station device operates as the second wireless base station device, and when the retransmit request is issued.
16 . A wireless communicating method in which a first wireless base station device and a second wireless base station device perform a collaborative transmission process for realizing the process to allow the wireless terminal device not to discard a packet on which decoding has failed but to combine the packet with a retransmitted packet and decode a resultant packet while controlling the retransmission of the packet according to transmission status information returned from the wireless terminal device, comprising:
transmitting by a first processor in the first wireless base station device as a first packet a new data packet or a retransmission data packet corresponding to a retransmit request from the first wireless base station device to the wireless terminal device when the retransmit request is issued to the collaborative transmission process by the wireless terminal device;
transferring by the first processor information about a second packet different from the first packet between the new data packet and the retransmission data packet from the first wireless base station device to the second wireless base station device; and
transmitting by a second processor in the second wireless base station device the second packet according to information transferred in the packet transferring step in synchronization with a transmission process of the first packet in the first packet transmitting step from the second wireless base station device to the wireless terminal device when the retransmit request is issued.
17 . A wireless communication system in which a plurality of wireless base station devices perform, a collaborative transmission process on a wireless terminal device, comprising:
the wireless terminal device including a processor;
wherein
the processor is configured to
receive a control channel only from a first wireless base station device; and to
receive data collaboratively transmitted by at least the first wireless base station device and the second wireless base station device based on the received control channel.
18 . The wireless communication system according to claim 17 , wherein
the first wireless base station device is a serving base station device for the wireless terminal device.
19 . A wireless communication terminal device which receives data from a plurality of wireless base station devices in a collaborative transmission, comprising a processor;
wherein
the processor is configured to
receive a control channel only from a first wireless base station device; and to
receive data collaboratively transmitted by at least a first wireless base station device and a second wireless base station device based on the received control channel.
20 . The wireless terminal device according to claim 10 , wherein
the first wireless base station device is a serving base station device for the wireless terminal device.
21 . A wireless communication method in which a plurality of wireless base station devices perform, a collaborative transmission process on a wireless terminal device, comprising:
receiving a control channel only from a first wireless base station device by a processor in the wireless terminal device; and
receiving by the processor data collaboratively transmitted by at least the first wireless base station device and the second wireless base station device based on the received control channel.
22 . The wireless communication method according to claim 21 , wherein
the first wireless base station device is a serving base station device for the wireless terminal device.