JP5348218B2 - Wireless communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize data transmission in consideration of a handover. <P>SOLUTION: A mobile station transmitting second data depending on first data received from a wireless base station has: a detector detecting that a handover is performed; and a controller controlling so that a switching timing of a transmission destination of the second data comes after a switching timing of a reception channel of the first data when the detection is performed. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to a radio communication system, and preferably to a mobile radio communication system adopting a W-CDMA (UMTS) communication system.

HSDPA (High Speed Downlink Packet A) is one of the data transmission methods using radio.
ccess) is now in practical use (see Non-Patent Document 1). HSDPA is a scheme that enables high-speed packet transmission in the downlink direction, and a maximum transmission rate of about 14 Mbps is possible.

HSDPA employs adaptive coding and modulation (AMC), for example, adaptively switching between QPSK modulation and 16-value QAM according to the radio environment between the base station and the mobile station. It is characterized by that.

HSDPA adopts an H-ARQ (Hybrid Automatic Repeat reQuest) system. In H-ARQ, when a mobile station detects an error in received data from a base station, it makes a retransmission request to the base station. Since the base station that has received this retransmission request retransmits the data, the mobile station performs error correction decoding using both the already received data and the retransmitted received data. Thus, in H-ARQ, even if there is an error, the number of retransmissions is suppressed by effectively using already received data.

The main radio channel used for HSDPA is HS-SCCH (High Speed-Shared Co).
ntrol Channel), HS-PDSCH (High Speed-Physical Downlink Shared Channel)
HS-DPCCH (High Speed-Dedicated Physical Control Channel).

HS-SCCH and HS-PDSCH are both shared channels in the downlink direction (that is, the direction from the base station to the mobile station), and HS-SCCH is a parameter related to data transmitted on the HS-PDSCH. Is a control channel for transmitting. The various parameters include, for example, modulation type (Modulation Scheme) information indicating which modulation method to use, the number of spreading codes to be assigned (number of codes), a pattern of rate matching processing to be performed before transmission, etc. Information.

On the other hand, the HS-DPCCH is in the uplink direction (ie, the direction from the mobile station to the base station).
Individual control channels. For example, it is used by a mobile station when transmitting the result of whether data received from a base station via HS-PDSCH is acceptable or not as an ACK signal and a NACK signal (response signal) to the base station. When the mobile station fails to receive data (when the received data is a CRC error, etc.), a NACK signal as a retransmission request is transmitted from the mobile station, so that the base station performs retransmission control. Become. In addition, when the radio base station cannot receive an ACK signal or a NACK signal (in the case of DTX), it also performs retransmission control, so that the mobile station may enter a DTX state in which neither an ACK signal nor a NACK signal is transmitted. One of them.

In addition, the HS-DPCCH is also used to transmit reception quality information (for example, SIR) of a received signal from the base station measured by the mobile station to the base station as CQI information (Channel Quality Indicator). Then, the base station changes the downlink transmission format according to the received CQI information. In other words, if the CQI information indicates that the downlink radio environment is good, the transmission format is switched to a modulation method capable of transmitting data at a higher speed, and conversely, the CQI information is not good in the downlink radio environment. , The transmission format is switched to a modulation scheme that transmits data at a lower speed (that is, adaptive modulation is performed).
・ "Channel structure"
Next, a channel configuration in HSDPA will be described.
FIG. 1 is a diagram for illustrating a channel configuration in HSDPA. W-CDMA is
Since the code division multiplexing system is adopted, each channel is separated by a code.

First, the channels not described will be briefly described.
CPICH (Common Pilot Channel) is a downlink common channel, and is a wireless zone (
Transmitted to all mobile stations in the cell).

The CPICH is a channel used for channel estimation, cell search, and a timing reference for other downlink physical channels in the same cell in a mobile station, and is a channel for transmitting a so-called pilot signal.

Next, channel timing relationships will be described with reference to FIG.
As shown in the figure, each channel constitutes one frame (10 ms) with 3 × 5 = 15 slots (each slot corresponds to a length of 2560 chips). As explained earlier, CPIC
Since H is used as a reference for other channels, P-CCPCH (not shown) and HS
-The head of the SCCH frame coincides with the head of the CPICH frame. Where H
The head of the S-PDSCH frame is delayed by two slots with respect to HS-SCCH or the like, but after the mobile station receives the modulation type information via HS-SCCH, the demodulation corresponding to the received modulation type is performed. This is because HS-PDSCH can be demodulated by the method. HS-SCCH and HS-PDSCH constitute one subframe with three slots.

HS-DPCCH is an uplink channel, and it is about 7 from reception of HS-PDSCH.
It includes a slot (1 slot length) to be used for transmitting an ACK / NACK signal, which is a response signal for confirming reception, from the mobile station to the base station after 5 slots have elapsed.

The HS-DPCCH is also used to periodically transmit CQI information for adaptive modulation control to the base station. Here, the CQI information to be transmitted is, for example, CQI
The reception environment (for example, CPI) measured during the period from 4 slots to 1 slot before I transmission
Calculated based on CH SIR measurement results).

The matter regarding HSDPA mentioned above is disclosed by the following nonpatent literature 1, for example.
3G TS 25.212 (3rd Generation Partnership Project: Technical Specification Group Radio Access Network; Multiplexing and channel coding (FDD)) V6.2.0 (June 2004)

According to the background art described above, the radio base station transmits CPICH on a common channel,
The mobile station transmits the CPICH reception quality (CPICH reception SIR) measured in the measurement section (A1 portion) as a parameter (CQI) for adaptive modulation control (A2 portion).
Then, the radio base station transmits a transmission advance notice of data to be transmitted based on the parameters (A
3), and then the data subjected to adaptive modulation control is transmitted (part A4), and the mobile station transmits the reception result (ACK signal or NACK signal) of this data (part A5).

By this series of procedures, data is transmitted by adaptive modulation control from transmission of a signal that affects adaptive modulation control, and further, the transmission result of transmission data is transmitted. Therefore, data transmission based on adaptive modulation control is performed. It will be executed steadily.

However, from transmission of A1 until transmission of A3 (A4) or A5 is performed (1 of data transmission)
There is a problem that the time required for the cycle) is very long.

  Here, this problem will be described with reference to FIG.

FIG. 2 is a diagram for explaining an operation at the time of handover in which this problem becomes significant.

The mobile station moves from the wireless zone 1 (cell 1) toward the wireless zone (cell 2) and performs processing for switching the wireless zone (cell) from 1 to 2.

As shown in the figure, assuming that the handover process is just performed between the subframe 6 and the subframe 7, one cycle of data transmission is not completed for the data portion indicated by the dotted frame in the figure, which hinders data transmission. You can see that

This is because the transmission of the ACK signal indicating the reception result for the third to fifth subframes of HS-SCCH (and the corresponding subframe of HS-PDSCH) transmitted in cell 1 is transmitted to cell 2. Therefore, in cell 1, reception confirmation cannot be performed.

Also, the 7th to 10th subframes of HS-SCCH transmitted in cell 2 (and corresponding H
S-PDSCH subframe) is related to adaptive modulation control based on CQI for CPICH transmitted in cell 1, and is not adaptive modulation control according to the reception environment.

Furthermore, the sixth subframe of HS-SCCH (and the corresponding subframe of HS-PDSCH) is transmitted by the mobile station in the middle of the corresponding subframe of HS-PDSCH.
Switch the source cell for receiving from 1 to 2, resulting in an error.
The transmission notice by subframe is wasted.

Focusing on one cycle of data transmission, if problematic data is included in the cycle, the corresponding HS-SCCH, HS-PDSCH, CQI, and ACK signals are similarly troubled. be able to.

As described above, since one cycle of data transmission is long, a data portion having a problem in a wide range is included before and after the handover.

Accordingly, one of the objects of the present invention is to realize data transmission considering handover.

One of the objects of the present invention is to maintain a procedure for retransmission control at the time of handover.

It is to be noted that the present invention is not limited to the above-described object, and is an effect derived from each configuration shown in the best mode for carrying out the invention described later, and has an effect that cannot be obtained by the conventional technique. Can be positioned as one.

(1) In the present invention, in the mobile station that transmits the second data according to the first data received from the radio base station, a detection unit that detects that the handover is performed, and the detection is performed In addition, a mobile station comprising a control unit that controls the switching timing of the transmission destination of the second data later than the switching timing of the reception channel of the first data is used.
(2) Further, the switching of the transmission destination of the second data is performed at least before the timing of transmitting the second data according to the first data transmitted first after the switching of the reception channel of the first data. The mobile station according to claim 1, wherein the mobile station is used.
(3) Further, the first data is HS-PDSCH, and the second data is AC
The mobile station according to claim 1, wherein the mobile station is a K signal or a NACK signal.
(4) The second data transmission destination is switched in order by switching the CPICH reception channel, switching the CQI transmission destination, switching the HS-SCCH reception channel, and the HS-PDSCH reception channel. 2. After switching, characterized in that
The mobile station described is used.
(5) In addition, when the transmission destination for the second data is switched by the handover, the control unit controls the frequency or spreading code used for transmission before and after the handover to be different. The mobile station described in (1) is used.
(6) In addition, when switching the transmission destination for the second data by the handover, the control unit makes the frequency and spreading code used for transmission the same before and after the handover. The mobile station described in (1) is used.
(7) In the present invention, a radio base station that transmits first data and receives second data from the mobile station according to the first data detects that the mobile station performs handover. And a second data corresponding to the first data transmitted by the mobile station before switching the reception channel of the first data when the detection is performed, A radio base station comprising an acquisition unit that acquires second data transmitted from the mobile station later is used.
(8) In addition, the acquisition unit may acquire from another radio base station that forms a handover destination radio zone of the mobile station, or may acquire by itself without going through another radio base station. The radio base station described in (7) is used.
(9) When the second data acquired by the acquisition unit indicates a reception error,
The wireless base station according to (7), further comprising: a transfer processing unit configured to transfer the first data related to the reception error to the handover destination wireless base station.

According to the present invention, it is possible to provide a radio base station and a mobile station that consider handover.

  In addition, it is possible to suppress the data portion that hinders handover.

  In addition, the retransmission control procedure is easily maintained during the handover.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[A] Description of First Embodiment In this embodiment, the order of channels to be switched when performing handover is devised.

That is, the mobile station receives second data (for example, first data) in response to reception of first data (for example, data transmitted via the first channel HS-PDSCH) received from the radio base station. Response signal (ACK signal, N) transmitted via HS-DPCCH, which is the second channel.
ACK signal)) is transmitted, but when the detection unit of the mobile station detects that the handover is performed, the control unit of the mobile station compares the second data with the switching timing of the reception channel for the first data. The transmission destination switching timing is controlled later.

This facilitates transmission of the second data to the radio base station forming the handover source radio zone (cell).

In particular, when a response signal indicating the reception result for the first data transmission is transmitted as the second data and the radio base station performs the retransmission control according to the content of the second data, unnecessary retransmission control occurs. Less likely to do.

Hereinafter, taking the HSDPA described above as an example, this device will be specifically described with reference to the drawings.

Of course, the present invention can be applied not only to HSDPA but also to other wireless communication systems that perform handover processing. In this case, it is most preferable to apply to a system that performs retransmission control (further, adaptive modulation control or the like) as in HSDPA.
・ "Configuration of mobile communication system"
FIG. 3 shows an example of the configuration of the mobile communication system according to the present invention. Various mobile communication systems are conceivable. Here, as in the description of the background art, W-CDMA (UM
It is assumed that the mobile communication system is based on TS) and supports HSDPA.

In the figure, 1 is a core network, 2 and 3 are radio base station controllers (RNC: Radio Ne)
twork Controller), 4 and 5 are demultiplexers, and 61 to 65 are radio base stations (BS).
option) and 7 indicate mobile stations (UE: User equipment), respectively.

The core network 1 is a network for performing routing in the mobile communication system. For example, the core network can be configured by an ATM switching network, a packet switching network, a router network, or the like.

The core network 1 is positioned as a host device of the radio base stations 61 to 65, is connected to other public networks (PSTN), etc., and the mobile station 7 can also communicate with a fixed telephone or the like. Yes.

The radio base station control devices 2 and 3 are similar to the core network component devices, and the radio base station 61
˜65 and is equipped with a function to control these radio base stations 61 to 65 (management of radio resources to be used, etc.). Also, a function for performing control related to a handover process for switching communication with the mobile station 7 from communication with the handover source radio base station to communication with the handover destination radio base station (a handover process function to be described later) Part 13
Is also provided.
・ "Serving RNC, Drift RNC"
Here, the concept of serving RNC (S-RNC) and drift RNC (D-RNC) will be described.

When the mobile station 7 originates and receives a call, the radio base station controller that was initially responsible for the processing is called a serving RNC (referred to as RNC 2 in FIG. 1).

Thereafter, when the mobile station 7 continues to communicate and moves in the right direction, the radio area formed by the radio line base station 64 subordinate to the RNC 3 from the radio area (cell) formed by the radio base station 63 subordinate to the serving RNC 2 (Cell).

At that time, since it is necessary to switch the radio base station 6 that performs radio communication with the mobile station 7, so-called handover processing (hard handover processing) is performed.

That is, the mobile station 7 switches so that the data transmitted to the radio base station 63 is transmitted to the radio base station 64. Further, the reception state received from the radio base station 63 is switched to the reception state received from the radio base station 64 (the data reception channel is switched to the handover destination).

Similarly, on the wireless base station side, the data transmission state from the wireless base station 63 to the mobile station 7 is switched to the data transmission state from the wireless base station 64 to the mobile station 7, and the channel for receiving data from the mobile station 7 is wirelessly connected. Switching from the base station 63 to the radio base station 64 is performed.

On the other hand, when exchanging data about the mobile station 7 with the core network side, the RNC serving as the window is a single RNC (serving RNC).

Therefore, the RNC 3 managing the handover destination radio base station 64 transfers the received signal from the mobile station 7 to the serving RNC 2 (may be transferred via the core network 1,
In the case where a direct connection line is provided between the RNCs 2 and 3, the transfer is performed via this direct connection line instead of the core network 1).

Then, for the mobile station 7, the RNC 2 functioning as a serving RNC receives the data received from the mobile station 7 via the subordinate radio base station before the handover process, and the mobile station 7 transferred from the RNC 3 after the handover process. The received data from is transferred to the core network 1 side.

  The RNC 3 is referred to as a drift RNC with respect to the serving RNC.

Of course, the same applies when a signal is transmitted in the downlink direction (from the core network 1 side to the mobile station 7 direction). First, if the signal is transmitted from the core network 1 to the serving RNC 2 and before the handover process, the serving RNC 2 If the mobile station 7 transmits data via the subordinate radio base station and the handover process is performed, the serving RNC 2
3 is transmitted to the mobile station 7 via the radio base station 6 under the drift RNC 3.

In addition, by assigning the functions of RNCs 2 and 3 to the radio base station 6 and the core network 1 side,
NC can also be omitted. For example, a handover processing function unit is provided on the core network 1 side, and a radio channel assignment control function and the like are given to the radio base station 6.

The example described above is a handover between radio base stations under different RNCs, but is also executed between radio base stations under the same RNC (for example, between 61 to 63). In this case, if the RNC is a serving RNC, the RNC transmits data from the mobile station 7 received by the subordinate radio base station to the core network 1 without being transferred to other RNCs. Data received from the network 1 can be transmitted from the subordinate radio base station to the mobile station 7 without being transferred to another RNC.

Even within one radio base station, for example, when a plurality of radio areas (sectors (cells)) are formed using a plurality of antennas, a handover process may be performed between sectors (cells). it can.

The demultiplexers 4 and 5 are provided between the RNC and the radio base station apparatus.
3, the signal addressed to each radio base station received from 3 is separated and output to each radio base station, and the signal from each radio base station is multiplexed and delivered to the corresponding RNC.

Of course, this demultiplexer can also be omitted by directly connecting the radio base station controller and a plurality of radio base stations.

The radio base stations 61 to 63 perform radio communication with the mobile station 7 while the radio resources are managed by the RNC 2 and the radio base stations 64 and 65 are managed by the RNC 3.

The mobile station 7 is located in the radio area (cell) of the radio base station 6, thereby establishing a radio line with the radio base station 6 and communicating with other communication devices via the core network 1. In addition, even when moving, it is possible to continue communication with other communication devices by switching the wireless base station of the communication partner by the handover process.

The above is the outline of the operation of the mobile communication system in the first embodiment shown in FIG. 3, but the configuration and operation of each node will be described in detail below.
・ "Radio base station controller 2 (3)"
FIG. 4 is a diagram illustrating a radio base station controller (RNC: Radio Network Controller).

In the figure, 10 is a first interface unit for communication with the demultiplexing device, 11 is a control unit for controlling the operation of each unit, and 12 is a second interface unit for communication with the core network side.

Preferably, as the first and second interface units, an interface unit that performs transmission according to the ATM system can be employed. Of course, transmission according to other methods can also be performed.

The control unit 11 controls the operation of each unit and performs handover processing function units 13 and 3G that perform the processing (transfer processing, radio channel allocation, etc.) related to the handover processing described above.
It also includes an upper layer processing unit 14 such as an RLC (RLC: Radio Link Control) layer defined in the PP mobile communication system.

Next, an operation when a signal from the core network 11 side is transmitted to the demultiplexer 4 (5) side will be described.

The control unit 11 sends the signal received from the core network 1 side to the second interface unit 12.
The data (for example, variable-length packet data) obtained by performing the termination process in (1) is divided into predetermined lengths to generate a plurality of RLC PDUs (Packet Data Units), for example.

The control unit 11 writes the serial number in the sequence number area of each divided RLC PDU in order to assign a serial number to each PDU. This sequence number is the mobile station 7 and the PD
Used to find out-of-order in U. When out-of-order occurs, a PDU sequence number that could not be received correctly from the mobile station is transmitted in order to perform retransmission control in the RLC layer, and this sequence number is received. Control unit 11 (upper layer processing function unit 14)
Retransmits the transmitted RLC PDU to the mobile station 7 (the transmitted RLC PDU is stored as a record in a memory or the like).

Now, the control unit 22 that has generated the RLC PDU collects a plurality of RLC PDUs, and performs HS processing.
-A signal in a format according to PDSCH FP (frame protocol) is generated, given to the first interface unit 20, for example, converted into ATM cells, and then sent to the demultiplexer 4 (5) side.
・ "Radio base stations 61-65"
FIG. 5 is a diagram illustrating a radio base station 6 (BS).

In the figure, reference numeral 15 denotes a first interface unit that performs termination processing on a signal that is separated and transmitted as a signal addressed to the own device from the demultiplexer 4 (5). The radio | wireless transmission / reception part for performing is shown.

Reference numeral 17 denotes data to be transmitted for retransmission in order to perform retransmission control by the H-ARQ described above, or data to be transmitted on the HS-PDSCH that is a shared channel, The memory | storage part for storing is shown.

Reference numeral 18 denotes a control unit that controls each unit and includes a downlink signal generation unit 19, an uplink signal processing unit 20, a retransmission management unit 21, an adaptive modulation management unit 22, an acquisition unit 23, a transfer processing unit 24, and a detection unit 25. .

Here, the downlink signal generation unit 19 performs downlink signals (CPICH, HS-SCCH, HS-PD
Data to be transmitted as data such as SCH), and the upstream signal processing unit 20
CQI information, ACK signal, NACK signal, etc. are extracted from (HS-DPCCH).

In addition, the retransmission management unit 21 manages retransmission control related to H-ARQ, and the acquisition unit 23 transmits CQI information and a response signal transmitted from another radio base station and transmitted from the mobile station 7, as will be described later. Conversely, the transfer processing unit 24 has a function of transferring the CQI information and the response signal received from the mobile station 7 to another radio base station.

The detection unit 25 detects that the mobile station 7 performs a handover. For example, based on reception quality information, handover request information, etc. transmitted from the mobile station 7, it is detected from the handover processing function unit 13 of the radio base station control device 2 (3) that the mobile station is to be handed over. can do. Of course, it can also detect itself based on the received signal from the mobile station 7.

  Next, the processing operation of data received from the demultiplexer 4 (5) will be described.

First, the HS-PDSCH frame received via the first interface unit 15 is input to the control unit 18.

The control unit 18 sends an MA addressed to a certain mobile station included in the received HS-PDSCH frame.
The Cd PDU is stored in the storage unit 17.

When it is detected that data can be transmitted to the mobile station via the shared channel HS-PDSCH, the MAC-d PDU addressed to the mobile station is stored from the storage unit 17.
Are sequentially extracted to generate a MAC-hs PDU including a plurality of MAC-d PDUs.
Note that the number of MAC-d PDUs to be extracted is selected so as to be within a transport block size determined by CQI information or the like.

The MAC-hs PDU forms one transport block and becomes a source of data transmitted to the mobile station 7 via the HS-PDSCH.

Note that the MAC-hs PDU includes a transmission sequence number (TSN) that is a sequence number assigned to each MAC-hs PDU, and even if the HS-PDSCH is transmitted to the mobile station 7 by being divided into a plurality of processes. The transport blocks can be rearranged according to the sequence number.

The MAC-hs PDU generated by the control unit 18 is stored in the storage unit 17 and input to the downlink signal generation unit 19 to perform error correction coding and error in order to perform retransmission control by H-ARQ. By performing processing such as detection coding, one subframe of HS-PDSCH is formed, and given to the radio transmission / reception unit 16 together with other signals, HS-PDSC
It is transmitted to the mobile station 7 via H.

However, as described above, prior to transmission of the HS-PDSCH, a transmission advance notice to the mobile station 7 is performed via the HS-SCCH.

That is, the control unit 18 gives data to be transmitted via the HS-SCCH to the downlink signal generation unit 19 before transmission of the HS-PDSCH, and the downlink signal generation unit 19 uses the HS-SCCH based on the given data. 1 subframe is generated and provided to the wireless transmission / reception unit 16.

The mobile station 7 that received the HS-PDSCH and received the HS-SCCH notice of transmission,
The reception result (ACK signal or NACK signal) of HS-PDSCH is transmitted via S-DPCCH.

When the uplink signal processing unit 20 of the radio base station 6 performs reception processing of the uplink signal (HS-DPCCH or the like) from the mobile station 7 and detects that the reception result is a NACK signal, the retransmission management unit 21
Notify

The retransmission management unit 21 reads the MAC-hs PDU that has failed to be transmitted from the storage unit 17,
Again, the signal is given to the downlink signal processing unit 19 to cause the wireless transmission / reception unit 16 to perform retransmission.

On the other hand, when the uplink signal processing unit 20 detects that the reception result of the HS-PDSCH is an ACK signal, the retransmission control is unnecessary, so the control unit 18 transmits the next new transport block. Therefore, the untransmitted (waiting for transmission order) MA stored in the storage unit 17
The C-d PDU is read, a new MAC-hs PDU is generated, and the downlink signal generation unit 19
To control the transmission to the wireless transmission / reception unit 16.

The above is the operation related to H-ARQ (retransmission control) in the radio base station. As described above, in HSDPA, since the radio base station 6 performs adaptive modulation control, the mobile station 7 periodically performs the operation. Receive CQI information.

Since the CQI information is received by the uplink signal processing unit 20, the uplink signal processing unit 20 gives this CQI information to the adaptive modulation management unit 22.

The CQI information corresponds to the reception quality (for example, reception SIR) of the downlink signal (for example, CPICH) transmitted from the radio base station 6 and received by the mobile station 7.

For example, a total of 30 types of CQI information 1 to 30 are prepared, the mobile station 7 selects and transmits CQI information corresponding to the reception quality, and the adaptive modulation management unit 22 receives the CQI information received from the mobile station 7.
The transmission format corresponding to the I information is designated to the radio transmission / reception unit 16 and the downlink signal generation unit 19, and the adaptive modulation / modulation control according to the format is executed.

As a transmission format, TBS (Transport Bl indicating the number of bits to be transmitted in one subframe is used.
ock Size) number of bits, number of spreading codes used for transmission, number of codes, QPSK,
A modulation type indicating a modulation method such as QAM can be mentioned.

Accordingly, by defining the CICH so that the better the SIR of the CPICH (the larger the SIR), the larger the CQI, and the larger the CQI, the corresponding number of TBS bits and the number of spreading codes are increased. The better the downlink signal reception quality, the higher the transmission speed is controlled (in contrast, the worse the reception quality is, the lower the transmission speed is controlled).

Since it is necessary to notify the mobile station 7 of these transmission formats, the adaptive modulation management unit 22 provides a notice before transmission of the HS-PDSCH that performs transmission by adaptive modulation control, as described above. As the HS-SCCH data to be transmitted, transmission format information is given to the downlink signal generation unit 19 and the transmission format information is transmitted to the mobile station 7 via the radio transmission / reception unit 16.

The above is the basic configuration and operation of the radio base station 6, but as described above, one radio base station 6 may form a plurality of radio areas (cells).

FIG. 6 shows a configuration in the case where one radio base station forms a plurality of radio areas.

Each configuration is basically the same as that in FIG. 5, but a plurality of (three in this case) wireless transmission / reception units 16 and control units 18 are provided for each wireless area (cell), and the first interface Part 1
5 is distributed to the corresponding control units 181 to 183, and the control unit 181.
183 to 183 execute processing equivalent to the control unit 18 described earlier (adaptive modulation control, retransmission control, etc.) separately for each assigned radio area.

Note that the storage unit 17 can also be used in common by each control unit.
・ "Mobile station 7"
Next, the configuration and operation of the mobile station will be described.

FIG. 7 shows the configuration of the mobile station 7. In the figure, 30 indicates a wireless transmission / reception unit for performing wireless communication with the wireless transmission / reception unit 16 of the wireless base station 6, and 31 indicates an input / output unit for input of voice, data, etc., and reception voice, data output Indicates.

Reference numeral 32 denotes a storage unit that stores various necessary data, and is also used to temporarily store data in which a reception error has occurred in order to realize H-ARQ.

Reference numeral 33 denotes a control unit that controls each unit. The CPICH processing unit 34, the HS-SCCH processing unit 35, the HS-PDSCH processing unit 36, the HS-DPCCH processing unit 37, and the upper layer processing unit 3
8. A detection unit 39 is provided.

The CPICH processing unit 34 performs reception processing of CPICH continuously transmitted from the radio base station 6 in a measurement section or the like, and measures the reception quality (reception SIR) measurement result in the HS-DPCCH processing unit 37.
To give. In addition, phase information on the IQ plane of the pilot signal obtained by the CPICH reception processing is given to the HS-SCCH processing unit 35, the HS-PDSCH processing unit 36, and the like to perform synchronous detection (
Channel compensation).

Note that the mobile station 7 periodically transmits CQI information for adaptive modulation control to the base station via the HS-DPCCH while receiving the HSDPA service. Here, the CQI information to be transmitted is, for example, CQI information corresponding to a result measured in a period from 3 slots before to 1 slot before CQI transmission.

The correspondence between the reception quality (reception SIR) and the CQI information is stored in the storage unit 32,
The CQI information to be transmitted can be determined by selecting the CQI information corresponding to the reception quality.

The HS-SCCH processing unit 35 performs HS-SCCH reception processing transmitted from the radio base station 6 for each subframe, and sends a transmission advance notice that data will be transmitted to the local station via the HS-PDSCH. Check if it has been.

That is, the first part of the HS-SCCH is received, and it is detected whether or not it has been transmitted to the own station based on the decoding result (for example, likelihood information) after multiplying by the code unique to the own station.

Here, when it is detected that it has been transmitted to its own station, the reception processing of the remaining second part is completed, and reception error detection is performed based on the error detection bits added to the entire first and second parts. I do. When the HS-SCCH processing unit 35 detects an error, the following process in the HS-PDSCH processing unit 36 can be interrupted because the detection of the advance notice is an error.

Now, the HS-SCCH processing unit 35 that has detected that there is a transmission notice addressed to its own station notifies the HS-PDSCH processing unit 36 to receive one subframe of the HS-PDSCH after two slots.

At that time, the code information and the modulation type information notified from the wireless base station 6 in part 1 of the HS-SCCH are also notified.

As a result, the HS-PDSCH processing unit 36 can start the HS-PDSCH reception process, and then transmits information necessary for other reception processes included in the remaining second part to the HS-S.
By obtaining from the CCH processing unit 35, HS-PDSCH reception processing (derate matching, error correction decoding, etc.) is completed, and error detection of the decoding result is performed.

Now, the HS-PDSCH processing unit 36 adds a CRC to the decoding result for the HS-PDSCH.
The HS-DPCCH processing unit 37 is notified of the presence or absence of an error. Also, the MAC obtained by decryption
-Hs Performs rearrangement processing (reordering) based on the TSN included in the PDU, and delivers the reordered data to the upper layer processing function unit 38.

The higher layer processing function unit 38 determines whether or not the sequence number included in the MAC-d PDU has an out-of-order, detects the out-of-order, and provides a dedicated channel separately provided for the radio base station controller 2 (3). And performing retransmission control in the RLC layer.

The received data acquired in order is sequentially output from the input / output unit 31 in a corresponding output format (audio output, image output, etc.).

The HS-DPCCH processing unit 37 stores a parameter (parameter CQI used for adaptive modulation control in the radio base station 6) corresponding to the reception quality given from the CPICH processing unit 34 in the storage unit 32 (CQI table). Select based on HS-DPCCH
To the wireless base station 6 via Further, in response to the error presence / absence notification from the HS-PDSCH processing unit 36, the HS-DPCCH processing unit 37 transmits the reception result as a response signal (ACK signal, NACK signal) via the HS-DPCCH.

That is, the HS-DPCCH processing unit 37 gives an ACK signal to the radio transmission / reception unit 30 if there is no error, and sends a NACK signal to the radio transmission / reception unit 30 if there is an error.

The detection unit 39 detects that a handover is necessary. For example, the mobile station 7 can be detected by notifying the handover instruction from the radio base station or the radio base station controller by transmitting the measured reception quality information to the radio base station.

With the above configuration, the mobile station 7 checks the HS-SCCH every subframe, and is notified that data transmission via the HS-PDSCH is performed to the mobile station 7.
One subframe of HS-PDSCH after the slot is received, demodulated, and decoded (turbo decoding) to obtain a decoding result, and whether reception is possible is determined by CRC calculation using CRC bits. The data is stored in the storage unit 32 and the NACK signal is sent to the HS-DPC.
It transmits to the radio base station 6 via the CH.

When retransmission is executed by the radio base station 6, the data stored in the storage unit 32 and the retransmitted data are combined and then decoded (turbo decoding). Perform CRC check again.

If it is determined that the CRC check is possible, the HS-DPCCH processing unit 37 performs HS-D
Control is performed to transmit an ACK signal to the radio base station 6 via the PCCH.

Further, rearrangement processing (reordering) is performed based on the TSN included in the MAC-hs PDU obtained by decoding, and the MAC-d PDU (RLC PDU) included in the transport block after the rearrangement is obtained. Delivered to the upper layer processing function unit 38.

The upper layer processing function unit 38 performs rearrangement (reordering) using the sequence number included in the RLC PDU, detects out of order, and checks the polling bit.

Here, when the out-of-order is detected, the RLC processing function unit of the mobile station 17 transmits the PDU that has not been correctly received for retransmission control in the RLC layer via the separately established dedicated physical channel (DPCH). The sequence number is transmitted to the radio base station controller 2 (3).

The ACK signal whose transmission is controlled by the upper layer processing function unit 38 of the mobile station 7 and the sequence number of the PDU that could not be received correctly are transmitted via the radio base station 6 and the demultiplexer 4 (5) to the radio base station controller 2. Sent to (3).

When the control unit 11 of the radio base station control device 2 (3) receives the sequence number that could not be correctly received from the upper layer processing unit 38 of the mobile station 7, the control unit 11 receives data (HS-PDSCH) to be retransmitted by retransmission control processing. Frame) is read from a storage unit (not shown) and retransmitted.

The above is the description of the configuration and operation of each device. Hereinafter, the operation at the time of handover will be described in detail.
・ Operation during handover
・ "Destination switching timing of response signal (ACK signal, NACK signal)"
FIG. 8 shows both uplink and downlink frame formats for explaining a channel switching procedure at the time of handover.

First, it is assumed that the mobile station 7 is in a wireless zone (in a cell) of any one of the wireless base stations 6 in FIG. 3 and is receiving HSDPA service. Here, it is assumed that the mobile station 7 is within the radio zone of the radio base station 61.

In this case, the mobile station 7 transmits the first data (for example, HS-) transmitted from the radio base station 61.
(Data received via PDSCH) is received by the HS-PDSCH processing unit 36 (HS of FIG. 8).
-Refer to the black portion of PDSCH), and the HS-DPCCH processing unit 37 sends the response signal (for example, a signal indicating the reception result of the ACK signal, the NACK signal, etc.) to the radio base station 61 as the second data. (Refer to the black-painted portion of HS-DPCCH in FIG. 8).

Based on the second data, the control unit 33 of the radio base station 61 performs retransmission control to retransmit data transmitted via the HS-PDSCH or to transmit new data.

However, as described with reference to FIG. 2, when a handover occurs in the middle, a data portion that causes trouble occurs (see data surrounded by a dotted frame in FIG. 2).

However, in FIG. 8, the control unit 33 of the mobile station 7 switches the channel for receiving the HS-PDSCH (switching from the radio base station 61 to 62) at timing C2 (within the seventh subframe) in the figure. At least at a later timing (eg, timing D1, D2 or any timing in between (preferably at the beginning of the slot)),
The HS-DPCCH processing unit 34 is controlled to switch the transmission destination of the response signal or the entire HS-DPCCH (switching from the radio base station 61 to 62).

Further, if the HS-PDSCH channel is switched at timing C1 (the head of the seventh subframe), timing D3 at least after timing C1.
From this point, a response signal (ACK signal, NACK signal) is transmitted toward the radio zone (cell 2) formed by the radio base station 62 that is the handover destination.

Here, D3 indicates a reception result of the HS-PDSCH already transmitted in the handover source radio zone before the timing C1, and a response signal (see F7 in the figure) transmitted after the timing C1 is the handover source. This is to transmit to the wireless zone. Of course, the transmission destination of the response signal (D1 or D2 after that)
Alternatively, the transmission destination of the entire HS-DPCCH) can be switched to the handover destination.

That is, it is guaranteed that the response signal transmitted before the switching is transmitted to the handover source radio zone by switching the transmission destination after the transmission of any of the response signals indicated by F7 to F10 is completed. It becomes.

Most preferably, the destination of all response signals F7 to F10 can be the handover source by switching after F10 is transmitted or by completing the switching by D2 at the latest.

When HS-PDSCH is switched at timing C1 or C2, the response signal to HS-PDSCH that starts transmission first after switching is transmitted in the eleventh subframe in the figure, but from this transmission timing, It is meaningful to switch the transmission destination of the response signal before D2, which is the previous timing.

In other words, since the HS-PDSCH is switched so as to be received from the handover destination radio base station, the response signal is switched so as to be transmitted to the handover destination radio base station accordingly, and the retransmission control cycle can be maintained. Because it can.

The detection unit 39 of the mobile station 7 needs to detect D3, D1, D2, etc., which are timings after C1 or C2 which are HS-PDSCH switching timings.
, C2, for example, can be easily recognized by being notified from the handover processing function unit 13 of the radio base station control device 2, and therefore any of 1.5 slot to 12.5 slot after this C1 as a reference It is only necessary to detect the switching timing that is the timing of 1) or the switching timing that is any timing after 1.5 slots to 10.5 slots after C2.

The handover source and destination radio base stations are also notified of the timings C1 and C2 from the radio base station controller 2 etc. Thus, the response signal can be accurately acquired.

In this embodiment, handover between different radio base stations has been described. However, the present invention can also be applied to handover within one radio base station having a plurality of sectors. In this case, not between different radio base stations, What is necessary is just to replace with the process in a different control part (181,182,183).
・ "Transfer process"
Further, in FIG. 8, even if the mobile station 7 switches the transmission destination of the response signal before transmitting any of the response signals indicated by F7 to F10, the radio base station 6 side can cope with it. It is also possible to facilitate retransmission control.

That is, in this case, the response signal (FN (N = N =
7 to 10)) are transmitted to the handover destination radio base station 62 while corresponding to the data received from the handover source radio base station 61 via the HS-PDSCH. The detection unit 25 of the base station 62 detects that the mobile station 7 has performed a handover, and the transfer processing unit 24 uses the response signals having different transmission destinations to form a radio base station 61 that forms a handover source radio zone. Is controlled to be transferred via the line Iur.

As a result, the handover source radio base station 61 can acquire the response signal transferred from the handover destination radio base station 62 by the acquisition unit 23, and can provide the response signal to the retransmission management unit 21. Can be done.

If the response signal transmission destination switching timing is devised as described above, the uplink signal processing unit 20 can directly acquire the response signal from the mobile station 7. The processing unit operates as an acquisition unit.

The above is the explanation of the idea about the switching timing of the transmission destination of the HS-DPCCH (response signal (ACK signal, NACK signal) indicating the reception result) as the second data. Furthermore, the switching timing of the CPICH reception channel is further described. It is more desirable to devise the above.
・ "CPICH reception channel switching timing"
For example, the control unit 33 (handover processing function unit 39) of the mobile station 7 switches the channel for receiving the HS-SCCH at the timing C1 (the top of the seventh subframe) in FIG. 8 (from the radio base stations 61 to 62). Switching), but at least before that (timing A1,
The CPICH processing unit 34 is controlled to switch the CPICH reception channel (switch from the radio base station 61 to 62) at A2 or the head of any slot between them.

For example, at timing A1 (about 0.5 slot of the third subframe), CPIC
If the H reception channel is switched, CPICH is received from the radio zone (cell 2) formed by the handover destination radio base station 62 over the period from 0.5 slot to 3 slots of the third subframe. It becomes.

Therefore, the CQI information that starts transmission with a one-slot delay after completion of CPICH reception (see timing B1) corresponds to the reception quality of CPICH received from the handover destination radio base station 62.

Therefore, this CQI information is transmitted, and as a result, the radio base station 62 (adaptive modulation management unit 22)
, The transmission format information at the time of transmission advance notice on the HS-SCCH (refer to the seventh subframe) transmitted by the radio base station 62 at a timing C1 delayed by about 5.5 slots from the transmission of this CQI information, This CQI information can be reflected. Of course, when transmitting HS-PDSCH that is transmitted with a delay of two slots, it is possible to transmit in this transmission format as well.

Similarly, in the eighth to tenth subframes, the adaptive modulation management unit 22 of the handover destination radio base station 62 can acquire the CQI information selected by the mobile station 7 based on the CPICH transmitted by the own station. It will be possible.

Accordingly, the handover processor function unit 39 of the mobile station 7 switches the reception quality measurement channel (CPICH) to the handover destination at the timing A1 before the timing C1 (C2), so that the HS-SCCH ( HS-PDSCH) has a problem after switching the receiving channel to the handover destination (for example, adaptive modulation control is not working properly)
Data will be reduced.

In addition, as a result, as shown in FIG. 8, the data portions (CQI, A
As a result, the CK signal) will be safe and one or more data transmission cycles will be improved.

Even when the control unit 33 switches the CPICH reception channel at the timing A2, the CQI information transmitted at the timing B2 in the figure and the corresponding HS-SCCH, 2 transmitted at the 10th subframe, 2 Since the slot-delayed HS-PDSCH and the ACK signal transmitted at the timing in the fourteenth subframe are similarly troublesome,
At least one data transmission cycle will be improved.

The handover processing function unit 39 of the mobile station 7 needs to detect timings A1, A2, etc., which are timings earlier than the timing C1, but the timing C1 is detected from the handover processing function unit 13 of the radio base station control device 2. By being notified, it can be easily recognized,
11.5 slots before (A1), 2.5 slots before (A2), etc.
It can be used as the switching timing of the transmission source radio base station for receiving the PICH. Other timings may be based on C1.

In addition, the handover source and destination radio base stations are notified of the timing C1 from the radio base station control device 2 or the like, so that any mobile base station can move as well as the mobile station. By specifying the reception timing of the CQI information whose transmission is started before the timing C1 from the station, the CQI information can be accurately acquired.

In this embodiment, handover between different radio base stations has been described. However, the present invention can also be applied to handover within one radio base station having a plurality of sectors. In this case, not between different radio base stations, What is necessary is just to replace with the process in a different control part (181,182,183).
・ "CQI destination switching timing"
Furthermore, the handover processing function unit 39 of the mobile station 7 that has switched the CPICH reception channel (to the handover destination) at the timing A1 receives the switched radio base station 62.
The CQI information selected according to the reception quality (reception SIR) of CPICH received from is transmitted, and the transmission destination is preferably a timing that is the transmission timing of the reception quality measured in the measurement period starting from the timing A1. It is preferable to switch at B1 (after timing A1 and before timings C1 and C2).

This is because the mobile station 7 moves the HS-SCCH reception channel to the handover destination (radio base station 62
This is because the CQI information necessary for generating the HS-SCCH to be received first after switching to (1) can be directly transmitted to the radio base station 62.

Of course, the transmission destination of the CQI information can be switched at timing B2 (after timings A1, A2, and C1).

However, in this case, the CQI information transmitted to the radio base station 61 in the period from the timing B1 to the timing B2 (however, this CQI information is based on the reception quality of the CPICH received from the radio base station 62). Is preferably transferred from the radio base station 61 to the radio base station 62.

That is, the wireless base station 61 recognizes that it is the handover source wireless base station (for example, the wireless base station control device 2 is instructed to hand over the mobile station 7 from the subframe 7 to the wireless base station 62). As shown in FIG. 5, since the transfer processing unit 24 is included, the CQI information received from the mobile station 7 is transferred to the handover destination radio base station 62 by the transfer processing unit 24. is there.

Therefore, before the CQI information is transmitted from the mobile station 7, the radio base station 62 acquires the CQI information received from the radio base station 61 via the radio base station controller 2 by the acquisition unit 23 and performs adaptive modulation. It can be given to the management unit 22.

In addition, when switching the transmission destination of the CQI information at timing B1, the uplink signal processing unit 20 of the radio base station 62 receives the CQI information directly from the mobile station 7. In this case, the uplink signal processing unit 20 acquires the CQI information. It will function as a part.

As described above, the retransmission control, adaptive modulation control, and composite control thereof are smoothly performed by devising the switching timing of each channel. Preferably, the switching timing of the CPICH reception channel (to the handover destination) It is desirable to perform switching in the order of switching timing of the transmission destination of CQI information (to the handover destination), switching timing of the HS-SCCH reception channel (to the handover destination), and switching timing of the transmission destination of the response signal.

For example, CPICH channel switching is performed at timing A1, and CTCH is performed at timing B1.
The transmission destination of QI information is switched, the reception channel of HS-SCCH is switched at C1, the reception channel of HS-PDSCH is switched at C2, and the transmission timing of response signals is switched at D1 to D2. It is desirable.

In the above-described embodiment, an example in which HS-SCCH and HS-PDSCH are continuously assigned to one mobile station 7 has been described. However, since it is a shared channel, it may be assigned to another mobile station. However, the mobile station that is the destination of the data to be improved by this embodiment can benefit from this improvement.

In addition, when the handover is performed between different RNCs, as described above, the serving RNC performs the lead processing, but the CQI information from the transfer processing unit 24 of the handover destination radio base station The serving RNC or the like (which may also be referred to as a drift RNC) transmits the CQI information to the drift RNC, and transmits the CQI information to the radio base station under the control of the drift RNC and the handover destination radio base station. It is sufficient to execute the transfer.

[B] Description of Second Embodiment In the first embodiment, the operation is described when there is no difference in frame timing between the handover source and handover destination radio zones (cells) or they can be ignored.

In addition, since it is easy to synchronize the frame timing between sectors in one radio base station, the situation as in the first embodiment is likely to occur.

However, in this embodiment, a case will be described in which there is a difference in frame timing between the handover source and handover destination radio zones (cells).

For example, handovers between different radio base stations (especially handover to different frequencies) and handovers to radio base stations under different RNCs (especially handovers of different frequencies) are in the situation as in the second embodiment. I think it tends to be.

FIG. 9 is a diagram showing a frame configuration when there is a frame timing shift (G in the figure) between the handover source and handover destination radio zones (cells).

When there is a deviation G in the frame timing before and after the handover, a process for compensating (absorbing) this deviation is required.

In this embodiment, after the mobile station 7 switches the HS-PDSCH reception channel, the HS-PDSCH transmission start timing C2 that is first received from the handover destination radio base station 6 is 2 from the top of the subframe 7. Consider not only the slot but also the G delay.

Here, the HS− transmitted from the handover source radio base station prior to the timing C2.
For PDSCH, the response signal is transmitted in accordance with the frame timing of the handover source radio base station, and for HS-PDSCH transmitted from the handover source radio base station after timing C2, the response signal is sent to the handover destination. Since transmission is performed in accordance with the frame timing of the radio base station, this shift is compensated between D1 and D2 in FIG.

That is, the transmission interval between the response signal transmission in the 10th frame and the transmission timing D2 of the response signal in the frame 11 is an interval obtained by adding the 2-slot shift time G. Is compensated.

In addition, as described above, when switching the transmission destination of CQI information is performed before switching timing C1 of the HS-SCCH reception channel (for example, timing B in the figure),
The I information is transmitted to the handover destination radio base station, and the response signal has a period (B to D1) in which it is transmitted to the radio base station before the handover.

In this period, the mobile station's 7 HS-DPCCH signal processing unit 37 includes a portion that transmits the CQI information and the response signal in a time-overlapping manner. By transmitting and transmitting to the handover destination radio base station at frequency f2 (f1 and f2 are different frequencies), overlapping transmission can be performed.

In addition, transmission is performed with a spreading code C1 for a handover source radio base station, and transmission is performed with a spreading code C2 for a handover destination radio base station (C1 and C2 have different spreading code patterns). be able to.

The other CPICH reception channel switching timing is CQI information (the seventh subframe in the figure) used for the HS-SCCH (about the seventh subframe in the figure) transmitted first after the HS-SCCH reception channel switching. CPICH to be performed to specify (within 4 subframes)
Start timing A2 (may be within the range of A1 to A2) of the reception quality measurement period of A1, and A1
It is desirable to compensate for the deviation between A2 and A2. It should be noted that processing necessary for switching the reception channel can be performed between A1 and A2.

[C] Description of Third Embodiment FIG. 10 is a diagram showing a frame configuration when there is a frame timing shift (G in the figure) between the handover source and handover destination radio zones (cells).

When there is a deviation G in the frame timing before and after the handover, a process for compensating (absorbing) this deviation is required.

In this embodiment, after the mobile station 7 switches the HS-PDSCH reception channel, the HS-PDSCH transmission start timing C2 that is first received from the handover destination radio base station 6 is 2 from the top of the subframe 7. Consider not only the slot but also the G delay.

Here, HS-PDSCH reception channel switching is performed from timing D1 at which a response signal for HS-PDSCH transmitted before switching of HS-SCCH and HS-PDSCH reception channels performed in C1 or C2 is completed. HS-PDSCH sent later
Response signal and C in any of the period up to timing D2 for transmitting the response signal
It is assumed that channel switching of the entire HS-DPCCH, which is a channel for transmitting QI information, is performed.

For example, as shown in the figure, until the timing D1, the entire HS-DPCCH (both CQI information and response signal) is transmitted in accordance with the transmission frame of the handover source radio base station, and at least from the timing D2, the handover destination radio is transmitted. HS according to the transmission frame of the base station
-By performing transmission of the entire DPCCH (both CQI information and response signal), the compensation of the shift time G is compensated by forming between the other mings D1 and B.

In this example, since the same transmission, reception frequency, spreading code, etc. are used before and after handover, and the radio base station of the communication partner can be simply switched, the load on the mobile station is small. It will be over.
[D] Description of Fourth Embodiment In the first embodiment, before switching the reception channel for the HS-PDSCH, the response signal for the HS-PDSCH transmitted from the handover-source radio base station is sent to the handover-source radio base. In this embodiment, countermeasures are taken when the response signal transmitted or transferred last to the handover source radio base station is a NACK signal (reception error). .

That is, the handover source radio base station 6 determines that the last transmitted or forwarded response signal is N
If it is an ACK signal, the transfer processing unit 24 reads out data related to the NACK signal from the storage unit 17 and transfers it to the handover destination radio base station.

Then, the handover destination radio base station stores the transferred data in the storage unit 17,
The data is stored as retransmission data to be transmitted to the mobile station 7, and the retransmission management unit 21 is notified to the mobile station 7 that retransmission is necessary.

In addition, when transferring by the transfer processing unit 24, it is desirable to transfer parameters required for retransmission control together. For example, by transferring information such as Xnd when performing retransmission control, the mobile station 7 can be made aware of retransmission.

It is a figure for showing the channel structure in HSDPA. It is a figure for demonstrating the operation | movement at the time of a hand-over. It is a figure which shows the mobile communication system which concerns on this invention. It is a figure which shows the radio base station control apparatus which concerns on this invention. It is a figure which shows the wireless base station (the 1) which concerns on this invention. It is a figure which shows the wireless base station (the 2) which concerns on this invention. It is a figure which shows the mobile station which concerns on this invention. It is a figure for demonstrating the operation | movement at the time of the handover which concerns on this invention. It is FIG. (1) for demonstrating the operation | movement (with frame shift | offset | difference) at the time of the handover which concerns on this invention. FIG. 8 is a diagram (part 2) for explaining the operation (with frame shift) at the time of handover according to the present invention;

1 Core network 2, 3 RNC
4, 5 Demultiplexer 6 Radio base station 7 Mobile station 10 First interface unit 11 Control unit 12 Second interface unit 13 Handover processing function unit 14 Upper layer processing function unit 15 First interface unit 16 Wireless transmission / reception unit 17 Storage unit 18 Control unit 19 Downstream signal generation unit 20 Upstream signal processing unit 21 Retransmission management unit 22 Adaptive modulation management unit 23 Acquisition unit 24 Transfer processing unit 25 Detection unit 30 Radio transmission / reception unit 31 Input / output unit 32 Storage unit 33 Control unit 34 CPICH processing unit 35 HS-SCCH processing unit 36 HS-PDSCH processing unit 37 HS-DPCCH processing unit 38 Upper layer processing function unit 39 Detection unit

Claims (2)

A base station,
Receiving a first signal transmitted from the base station via a shared channel, receiving a second signal transmitted from the base station according to the first signal, and according to a second signal; A mobile station that transmits a third signal to the base station,
When the mobile station performs handover, the mobile station receives the first signal from the handover destination base station before stopping the transmission process via the channel that transmits the third signal to the handover source base station. A wireless communication system, which starts processing. The channel for transmitting the third signal to the base station of the handover source before stopping the process of receiving the second signal transmitted from the base station of the handover source when the mobile station performs the handover wireless communication system according to claim 1 wherein before stopping the transmission process, characterized that you start the reception processing of the first signal from the handover destination base station through.

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