Radio base station device and mobile communication system

• US 7,418,273 B2
• Filed: 06/19/2003
• Issued: 08/26/2008
• Est. Priority Date: 06/19/2003
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Tomoe, Naohito, Suyama, Syouhei
• Primary Examiner(s): Corsaro; Nick
• Assistant Examiner(s): Ajayi; Joel
• Application Number:
  US10/558,196
• Publication Number:
  US 20060215592A1
• Time in Patent Office: 1,895 Days
• Field of Search: None
• US Class Current: 455/561
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 69/22 Parsing or analysis of headers
• CPC Class Codes: H04W 36/0016 Hand-off preparation specially adapted for end-to-end data sessions
• CPC Class Codes: H04W 36/00692 using simultaneous multiple data streams, e.g. cooperative multipoint [CoMP], carrier aggregation [CA] or multiple input multiple output [MIMO] allocation of physical resources in CoMP or in CA H04L5/0035
• CPC Class Codes: H04W 36/02 Buffering or recovering information during reselection ; Modification of the traffic flow during hand-off
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• CPC Class Codes: H04W 40/248 Connectivity information update
• CPC Class Codes: H04W 40/36 due to handover
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]

Abstract

When carrying out a downlink handover, a source base transceiver station from which a mobile node is moving receives packets to be transmitted, via a wireless section, to the mobile node from an IP network, and copies and transfers them to a destination base transceiver station to which the mobile node is moving. On the other hand, when carrying out an uplink handover, the source base transceiver station compares the reliability of transport blocks which are received via a wireless section, from the mobile node and which are demodulated and decoded by the local station with that of transport blocks which are received via an IP network, from another base transceiver station and which are demodulated and decoded thereby, packetizes selected transport blocks with a better quality, and transmits them to a communications-partner node according to a route table, thereby implementing distribution of traffic via the IP network.

Claims

1. A base transceiver station apparatus comprising:

an analyzing means for analyzing a header of an IP packet received by the base transceiver station apparatus;

a routing means for transferring said IP packet to another base transceiver station based on a route table when a result of analyzing said header by said analyzing means indicates that said IP packet is not destined for the local base transceiver station, and for transferring said IP packet to a transmitting unit of the local base transceiver station when the result of analyzing said header by said analyzing means indicates that said IP packet is destined for the local base transceiver station; and

said transmitting unit including a means for, when transmitting a packet to a mobile node which is communicating with the local base transceiver station, acquiring a base station control packet sent from an RNC via said routing means, and dividing and converting transmission processing information on said mobile node into plural pieces of information in units of TTI in which information is transferred between L1 and MAC based on said base station control packet, said TTI being equal to a-time interval during which information is transmitted between layers of transport block set, an error correction coding means for inputting said transport blocks into which the transmission processing information is divided and converted, and for error correction coding said transport blocks, a modulating means for inputting the coded data outputted from said error correction coding means, and for modulating the coded data, and a transmitting means for converting digital baseband data which is the modulated, coded data output by said modulation means into an analog baseband signal, for converting a frequency of the analog baseband signal to a transmission carrier frequency, for performing a band limit on the analog baseband signal on the transmission carrier frequency and for amplifying it so that it has desired transmission power, and for separating signals lying within a transmission frequency band and signals lying within a reception frequency band from each other using a duplexer so as to transmit the analog baseband signal on the transmission carrier frequency and having the desired transmission power, as a radio signal, to said mobile node via a transmit/receive antenna.

2. The base transceiver station apparatus according to claim 1, further comprising:

a demodulating/calculating means for receiving a radio signal transmitted by the mobile node via the transmit/receive antenna, for separating signals lying within a transmission frequency band and signals lying within a reception frequency band from each other using a duplexer so as to amplify the received radio signal and perform a band limit on the received radio signal, for carrying out frequency conversion of the radio signal having a carrier frequency to generate an analog baseband signal, for converting the analog baseband signal into a digital baseband signal, for demodulating the digital baseband signal, and for calculating an SIR;

an error correction decoding means for performing error correction decoding on the demodulated data output from said demodulating/calculating means, and for calculating a CRC;

a packet generating/converting means for packetizing transport blocks which are the decoded data in units of TTI which are output by said error correction decoding means, the CRC indicating the decoded result, and an average SIR calculation result which is an average of calculation results of said SIR in units of said TTI into packets;

a packet sending means for, when said mobile node is carrying out a handover to move from a source base transceiver station to a destination base transceiver station which is the local base transceiver station, sending the generated packets, into which the transport blocks and so on have been converted, to said source base transceiver station;

an output means for, when said mobile node is carrying out a handover to move from a source base transceiver station which is the local base transceiver station to a destination base transceiver station, acquiring the packets sent to the local base transceiver station, via the routing means and the means for dividing/converting each of the sent packets into transport blocks, for comparing reliability of a transport block contained in a payload of each of packets received by the local base transceiver station with that of a transport block contained in a payload of each of the packets sent from said destination base transceiver station by comparing said calculated CRC and average SIR of each of the received packets with those of each of the packets sent from said destination base transceiver station, and for outputting selected transport blocks; and

an RNC transmitting means for packetizing only the transport blocks outputted by said output means into packets, and for transmitting the packets to the RNC via an IP network.

3. The base transceiver station apparatus according to claim 1, further comprising:

a means for, when a difference between reception power of a cell search signal outputted by a source base transceiver station with which the mobile node is currently communicating and from which the mobile node is moving, and reception power of a cell search signal outputted by the local base transceiver station which provides a cell adjacent to that of the source base transceiver station falls within a predetermined threshold, receiving a connection request transmitted to the local base transceiver station, which provides the adjacent cell and which is determined to output a cell search signal whose reception power differs from that of the cell search signal outputted from the source base transceiver station by the threshold or less, from the mobile node, said connection request including an identifier of the source base transceiver station;

a means for packetizing a base-station-to-base-station message to carry out communications between the local base transceiver station and the source base transceiver station, in order to make a request of the source base transceiver station to transfer a packet destined for said mobile node to the local base transceiver station; and

a means for, when the local base transceiver station is the source base transceiver station, transferring the packet destined for said mobile node to another base transceiver station which provides a cell adjacent to that of the local base transceiver station and which is determined to output a cell search signal whose reception power differs from that of the cell search signal outputted from the local base transceiver station by the threshold or less in response to a packet transfer request from the other base transceiver station using the routing means, and for outputting the same packet to the local station'"'"'s transmitting unit using said routing means so as to transmit a radio signal associated with the packet from the local base transceiver station to the mobile node.

4. The base transceiver station apparatus according to claim 1, wherein the routing means includes a means for, when said mobile node is carrying out a handover to move from a source base transceiver station which is the local base transceiver station to a destination base transceiver station, and the analyzing means determines that the received IP packet is a packet which requests real time processing based on priority information and a flow label as a result of the analysis of the header of the received IP packet, giving a higher priority to the packet than to other packets so that it gets ahead of the other packets to output the packet to either a means, which is the transmitting means, for dividing and converting a packet into transport blocks, or a means for comparing generated transport blocks into which a packet is converted by the local base transceiver station, with transport blocks which are obtained from said received IP packet through said routing means and the means for dividing and converting said IP packet into the transport blocks, and which are generated and converted by the destination base transceiver station to select either the former transport blocks or the latter transport blocks, and for outputting the selected transport blocks.

5. A mobile communications system comprising:

two base transceiver station apparatus according to claim 1;

an IP network disposed between said two base transceiver station apparatus, for connecting between said two base transceiver station apparatus;

an IP backbone network which connects said IP network disposed between said two base transceiver station apparatus with another IP network; and

a boundary router which connects said two base transceiver station apparatus to said IP backbone network.

6. A mobile communications system comprising:

two base transceiver station apparatus according to claim 2;

an IP network disposed between said two base transceiver station apparatus, for connecting between said two base transceiver station apparatus;

an IP backbone network which connects said IP network disposed between said two base transceiver station apparatus with another IP network; and

a boundary router which connects said two base transceiver station apparatus to said IP backbone network.

7. A mobile communications system comprising:

two base transceiver station apparatus according to claim 3;

an EP network disposed between said two base transceiver station apparatus, for connecting between said two base transceiver station apparatus;

an IP backbone network which connects said IP network disposed between said two base transceiver station apparatus with another IP network; and

a boundary router which connects said two base transceiver station apparatus to said IP backbone network.

8. A mobile communications system comprising:

two base transceiver station apparatus according to claim 4;

an IP network disposed between said two base transceiver station apparatus, for connecting between said two base transceiver station apparatus;

an IP backbone network which connects said IP network disposed between said two base transceiver station apparatus with another IP network; and

a boundary router which connects said two base transceiver station apparatus to said IP backbone network.

9. A base transceiver station apparatus comprising:

an analyzing means for analyzing a header of an IP packet received by the local base transceiver station;

a routing means for transferring said IP packet to another base transceiver station based on a route table when a result of analyzing said header by said analyzing means indicates that said IP packet is not destined for the local base transceiver station, and for transferring said IP packet to a transmitting unit of the local base transceiver station when the result of analyzing said header by said analyzing means indicates that said IP packet is destined for the local base transceiver station; and

said transmitting unit including a means for, when transmitting a packet to a mobile node which is communicating with the local base transceiver station, acquiring a base station control packet sent from an RNC via said routing means, and dividing and converting transmission processing information on said mobile node into plural pieces of information in units of TTI in which information is transferred between L1 and MAC based on said base station control packet, said TTI being equal to a time interval during which information is transmitted between layers of transport block set, an error correction coding means for inputting said transport blocks into which the transmission processing information is divided and converted, and for error correction coding said transport blocks, a modulating means for inputting the coded data outputted from said error correction coding means, and for modulating the coded data, and a transmitting means for converting digital baseband data which is the modulated, coded data output by said modulation means into an analog baseband signal, for converting a frequency of the analog baseband signal to a carrier frequency, for performing a band limit on the analog baseband signal and for amplifying it so that it has desired transmission power, and for separating signals lying within a transmission frequency band and signals lying within a reception frequency band from each other using a duplexer so as to transmit the analog baseband signal having the desired transmission power, as a radio signal, to said mobile node via a transmit/receive antenna,

and wherein said means for dividing and converting a packet into transport blocks comprises;

a storing means for outputting the divided and converted transport blocks to the error correction coding means at a next stage, and for storing the transport blocks in a temporary memory;

another storing means for outputting the transport blocks stored in said temporary memory to the error correction coding means in response to a resending request (NACK) from the mobile node again, and for storing said transport blocks in said temporary memory again;

an erasing means for erasing the transport blocks which the mobile node has finished receiving from said temporary memory in response to an acknowledgment signal (ACK) indicating the reception of the packet from said mobile node;

a means for, when said mobile node is carrying out a handover to move from a source base transceiver station which is the local base transceiver station to a destination base transceiver station, transferring the packet to the destination base transceiver station;

a handover means for, when said mobile node is carrying out a handover to move from a source base transceiver station to a destination base transceiver station and the local base transceiver station is either the source base transceiver station or the destination base transceiver station, performing a handover using SSDT so as to output the packet to the local station'"'"'s error correction coding means when determining that the local base transceiver station is a primary cell, and so as not to output the packet to the local station'"'"'s error correction coding means when determining that the local base transceiver station is a non-primary cell; and

a means for transferring the packet to either the local station'"'"'s internal circuit block or the destination base transceiver station regardless of whether a base transceiver station which has transmitted a packet to the mobile node last time is the source base transceiver station or the destination base transceiver station so as to resend the packet in response to said resending request when the local base transceiver station is a primary cell now.

10. The base transceiver station apparatus according to claim 9, further comprising:

a demodulating/calculating means for receiving a radio signal transmitted by the mobile node via the transmit/receive antenna, for separating signals lying within a transmission frequency band and signals lying within a reception frequency band from each other using a duplexer so as to amplify the received radio signal and perform a band limit on the received radio signal, for carrying out frequency conversion of the radio signal having a carrier frequency to generate an analog baseband signal, for converting the analog baseband signal into a digital baseband signal, for demodulating the digital baseband signal, and for calculating an SIR;

an error correction decoding means for performing error correction decoding on the demodulated data output from said demodulating/calculating means, and for calculating a CRC;

a packet generating/converting means for packetizing transport blocks which are the decoded data in units of TTI which are output by said error correction decoding means, the CRC indicating the decoded result, and an average SIR calculation result which is an average of calculation results of said SIR in units of said TTI into packets;

a packet sending means for, when said mobile node is carrying out a handover to move from a source base transceiver station to a destination base transceiver station which is the local base transceiver station, sending the generated packets, into which the transport blocks and so on have been converted, to said source base transceiver station;

an output means for, when said mobile node is carrying out a handover to move from a source base transceiver station which is the local base transceiver station to a destination base transceiver station, acquiring the packets sent to the local base transceiver station, via the routing means and the means for dividing/converting each of the sent packets into transport blocks, for comparing reliability of a transport block of each of packets received by the local base transceiver station with that of a transport block of each of the packets sent from said destination base transceiver station by comparing said calculated CRC and average SIR of each of the received packets with those of each of the packets sent from said destination base transceiver station, and for outputting selected transport blocks;

an RNC transmitting means for packetizing only the transport blocks outputted by said output means, and for transmitting them to the RNC via an IP network;

a detecting means for detecting a primary cell/non-primary cell specification bit contained in the data which is received from said mobile node and which is demodulated;

another output means for dividing and converting a packet including said primary cell/non-primary cell specification bit into transport blocks, for storing the converted transport blocks in a temporary memory, and for outputting the converted transport blocks to an ARQ control means and a scheduling means which determine whether to resend a requested packet to the mobile node, or to transfer the requested packet to be resent to the destination base transceiver station; and

an updating means for updating the route table based on the primary cell/non-primary cell specification bit for transfer of the requested packet to be resent to the mobile node to the destination base transceiver station.

11. The base transceiver station apparatus according to claim 9, further comprising:

a means for, when a difference between reception power of a cell search signal outputted by a source base transceiver station with which said mobile node is currently communicating and from said mobile node is moving, and reception power of a cell search signal output by the local base transceiver station which provides a cell adjacent to that of the source base transceiver station falls within a predetermined threshold, receiving a connection request transmitted to the local base transceiver station, which provides the adjacent cell and which is determined to output a cell search signal whose reception power differs from that of the cell search signal outputted from the source base transceiver station by the threshold or less, from the mobile node, said connection request including an identifier of the source base transceiver station;

a means for, when the local base transceiver station provides the adjacent cell and is determined to output a cell search signal whose reception power differs from that of the cell search signal outputted from the source base transceiver station by the threshold or less, making a request of the source base transceiver station to transfer the packet destined for said mobile node to the other base transceiver station;

a means for, when the local base transceiver station is the source base transceiver station, transferring the packet destined for said mobile node to another base transceiver station which provides a cell adjacent to that of the local base transceiver station and which is determined to output a cell search signal whose reception power differs from that of the cell search signal outputted from the local base transceiver station by the threshold or less in response to a packet transfer request from the other base transceiver station using the routing means, and for outputting the same packet to the local station'"'"'s transmitting unit using said routing means so as to transmit a radio signal associated with the packet from the local base transceiver station towards the mobile node;

a means for, when the local base transceiver station is the source base transceiver station, transmitting the radio signal based on said primary cell/non-primary cell specification bit to the mobile node when the local base transceiver station is a primary cell, and for transmitting no radio signal to the mobile node when the local base transceiver station is a non-primary cell; and

a means for, when the local base transceiver station is the source base transceiver station, allowing only the local base transceiver station itself to store the transport blocks into which the packet is converted in the temporary memory in order to resend the packet to the mobile node.

12. A mobile communications system comprising:

two base transceiver station apparatus according to claim 9;

an IP network disposed between said two base transceiver station apparatus, for connecting between said two base transceiver station apparatus;

an IP backbone network which connects said IP network disposed between said two base transceiver station apparatus with another IP network; and

a boundary router which connects said two base transceiver station apparatus to said IP backbone network.

13. A mobile communications system comprising:

two base transceiver station apparatus according to claim 10;

an IP network disposed between said two base transceiver station apparatus, for connecting between said two base transceiver station apparatus;

an IP backbone network which connects said IP network disposed between said two base transceiver station apparatus with another IP network; and

a boundary router which connects said two base transceiver station apparatus to said IP backbone network.

14. A mobile communications system comprising:

two base transceiver station apparatus according to claim 11;

an IP network disposed between said two base transceiver station apparatus, for connecting between said two base transceiver station apparatus;

an IP backbone network which connects said IP network disposed between said two base transceiver station apparatus with another IP network; and

a boundary router which connects said two base transceiver station apparatus to said IP backbone network.

15. A base transceiver station apparatus comprising:

an analyzing means for analyzing a header of an IP packet received by the base transceiver station apparatus;

a routing means for transferring said IP packet to another base transceiver station based on a route table when a result of analyzing said header by said analyzing means indicates that said IP packet is not destined for the local base transceiver station, and for transferring said IP packet to a transmitting unit of the local base transceiver station when the result of analyzing said header by said analyzing means indicates that said IP packet is destined for the local base transceiver station; and

said transmitting unit including a means for, when transmitting a packet to a mobile node which is communicating with the local base transceiver station, acquiring a base station control packet sent from an RNC via said routing means, and dividing and converting transmission processing information on said mobile node into plural pieces of information in units of TTI in which information is transferred between L1 and MAC based on said base station control packet, said TTI being equal to a time interval during which information is transmitted between layers of transport block set, an error correction coding means for inputting said transport blocks into which the transmission processing information is divided and converted, and for error correction coding said transport blocks, a modulating means for inputting the coded data outputted from said error correction coding means, and for modulating the coded data, and a transmitting means for converting digital baseband data which is the modulated, coded data output by said modulation means into an analog baseband signal, for converting a frequency of the analog baseband signal to a carrier frequency, for performing a band limit on the analog baseband signal and for amplifying it so that it has desired transmission power, and for separating signals lying within a transmission frequency band and signals lying within a reception frequency band from each other using a duplexer so as to transmit the analog baseband signal having the desired transmission power, as a radio signal, to said mobile node via a transmit/receive antenna,

wherein said means for dividing and converting a packet into transport blocks comprises;

a storing means for outputting the divided and converted transport blocks to the error correction coding means at a next stage, and for storing the transport blocks in a temporary memory;

another storing means for outputting the transport blocks stored in said temporary memory to the error correction coding means in response to a resending request (NACK) from the mobile node, and for storing said transport blocks in said temporary memory again;

an erasing means for erasing the transport blocks which the mobile node has finished receiving from said temporary memory in response to an acknowledgment signal (ACK) indicating the reception of the packet from said mobile node; and

a first transferring means for, when said mobile node is carrying out a handover to move from a source base transceiver station which is the local base transceiver station to a destination base transceiver station, transferring the packet to the destination base transceiver station;

a handover means for, when said mobile node is carrying out a handover to move from a source base transceiver station to a destination base transceiver station and the local base transceiver station is either the source base transceiver station or the destination base transceiver station, performing a handover using SSDT so as to output the packet to the local station'"'"'s error correction coding means when determining that the local base transceiver station is a primary cell, and so as not to output the packet to the local station'"'"'s error correction coding means when determining that the local base transceiver station is a non-primary cell; and

a second transferring means for transferring the packet to either the local station'"'"'s internal circuit block or the destination base transceiver station regardless of whether a base transceiver station which has transmitted a packet to the mobile node last time is the source base transceiver station or the destination base transceiver station so as to resend the packet in response to said resending request when the local base transceiver station is a primary cell now;

a means for receiving an MIMO transmission request signal, which is transmitted by said mobile node when receiving cell search signals transmitted by two or more base transceiver stations including the local base transceiver station, each of the two or more cell search signals having reception power which exceeds a predetermined threshold, determining that it can carry out communications with the two or more base transceiver stations simultaneously, and requiring higher-speed packet communications, via the transmit/receive antenna, and for detecting MIMO transmission request data from the error correction decoding means;

a means for transferring transport blocks to the two or more base transceiver stations which have transmitted cell search signals having reception power exceeding the predetermined threshold and which have IP addresses respectively corresponding to cell identifiers which are transmitted from the mobile node;

a means for deriving parameters required for MIMO transmission including a coding rule, a modulation rule, and a number of pilot symbols for estimation of a transmission route via which data is to be transmitted to the mobile node based on transfer rate information which is included in the detected MIMO transmission request data and which is requested by the mobile node; and

a means for, when the local base transceiver station has been communicating with the mobile node since before receiving the MIMO transmission request signal, transferring transport blocks to a cell identifier of the local base transceiver station, and for packetizing the parameters required for MIMO transmission including said encoding rule, said modulation rule, and said number of pilot symbols into packets to transmit them onto an IP network.

16. The base transceiver station apparatus according to claim 15, further comprising:

a demodulating/calculating means for receiving a radio signal transmitted by the mobile node via the transmit/receive antenna, for separating signals lying within a transmission frequency band and signals lying within a reception frequency band from each other using a duplexer so as to amplify the received radio signal and perform a band limit on the received radio signal, for carrying out frequency conversion of the radio signal having a carrier frequency to generate an analog baseband signal, for converting the analog baseband signal into a digital baseband signal, for demodulating the digital baseband signal, and for calculating an SIR;

an error correction decoding means for performing error correction decoding on the demodulated data output from said demodulating/calculating means, and for calculating a CRC;

a packet generating/converting means for packetizing transport blocks which are the decoded data in units of TTI which are output by said error correction decoding means, the CRC indicating the decoded result, and an average SIR calculation result which is an average of calculation results of said SIR in units of said TTI into packets;

a packet sending means for, when said mobile node is carrying out a handover to move from a source base transceiver station to a destination base transceiver station which is the local base transceiver station, sending the generated packets, into which the transport blocks and so on have been converted, to said source base transceiver station;

an output means for, when said mobile node is carrying out a handover to move from a source base transceiver station which is the local base transceiver station to a destination base transceiver station, acquiring the packets sent to the local base transceiver station, via the routing means and the means for dividing/converting each of the sent packets into transport blocks, for comparing reliability of a transport block of each of packets received by the local base transceiver station with that of a transport block of each of the packets sent from said destination base transceiver station by comparing said calculated CRC and average SIR of each of the received packets with those of each of the packets sent from said destination base transceiver station, and for outputting selected transport blocks;

an RNC transmitting means for packetizing only the transport blocks outputted by said output means, and for transmitting them to the RNC via the IP network;

a detecting means for detecting a primary cell/non-primary cell specification bit contained in the data which is received from said mobile node and which is demodulated;

another output means for dividing and converting a packet including said primary cell/non-primary cell specification bit into transport blocks, for storing the converted transport blocks in a temporary memory, and for outputting the converted transport blocks to an ARQ control means and a scheduling means which determine whether to resend a requested packet to the mobile node, or to transfer the requested packet to be resent to the destination base transceiver station; and

a means for updating the route table based on the primary cell/non-primary cell specification bit for transfer of the requested packet to be resent to the mobile node to the destination base transceiver station,

wherein said error correction decoding means comprises an MIMO transmission request signal detecting means for detecting whether or not the decoded data includes an MIMO transmission request,

when detecting the MIMO transmission request, said MIMO transmission request signal detecting means notifies the detection to a base station control unit,

said base station control unit comprises a means for deriving parameters required for MIMO transmission such as a coding rule, a modulation rule, information which is to be transmitted to the mobile node for estimation of a transmission route, based on transfer rate information which is requested by said mobile node and which is included in the MIMO transmission request data, and a means for generating transport blocks and a base-station-to-base-station communication message for transferring the parameters required for MIMO transmission based on identifier information indicating base transceiver stations which are determined to provide cell search signal reception power which exceeds the predetermined threshold by the mobile node as a result of performing cell search, the identifier information being contained in the MIMO transmission request data, and for packetizing and transmitting them to base transceiver stations having IP addresses which respectively correspond to identifiers of said base transceiver stations which are determined to provide cell search signal reception power which exceeds the predetermined threshold by the mobile node, and

said base transceiver station apparatus further comprises a means for determining transport blocks which are to be transmitted to other base transceiver stations which perform MIMO transmission based on the transfer rate information included in said MIMO transmission request, and a number of the cell identifiers of said plurality of base transceiver stations.

17. The base transceiver station apparatus according to claim 15, wherein each of the other base transceiver stations which perform MIMO transmission comprises a means for, in the base station control unit which manages control of the local base transceiver station, analyzing a base-station-to-base-station message from packets received from a base transceiver station which has been communicating with the mobile node since before the MIMO transmission request is made,

and said base station control unit comprises a means for controlling the error correction coding means and modulating means of the local base transceiver station, based on MIMO transmission parameters contained in the base-station-to-base-station message, to carry out MIMO transmission.

18. A mobile communications system comprising:

two base transceiver station apparatus according to claim 15;

an IP network disposed between said two base transceiver station apparatus, for connecting between said two base transceiver station apparatus;

an IP backbone network which connects said IP network disposed between said two base transceiver station apparatus with another EP network; and

a boundary router which connects said two base transceiver station apparatus to said IP backbone network.

19. A mobile communications system comprising:

two base transceiver station apparatus according to claim 16;

an IP network disposed between said two base transceiver station apparatus, for connecting between said two base transceiver station apparatus;

an IP backbone network which connects said IP network disposed between said two base transceiver station apparatus with another IP network; and

a boundary router which connects said two base transceiver station apparatus to said IP backbone network.

20. A mobile communications system comprising:

two base transceiver station apparatus according to claim 17;

an IP network disposed between said two base transceiver station apparatus, for connecting between said two base transceiver station apparatus;

an IP backbone network which connects said IP network disposed between said two base transceiver station apparatus with another IP network; and

a boundary router which connects said two base transceiver station apparatus to said IP backbone network.