JP2012124910A - Mobile station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a data transmission taking into account a handover capable of reducing a data part which may cause a problem, while maintaining a procedure for an adaptive modulation control.SOLUTION: A mobile station receives a first signal indicating a transmission format of data to be transmitted from a base station, receives a second signal including the data transmitted from the base station in accordance with the first signal, and transmits a third signal to the base station in accordance with the second signal. The mobile station has a control part to start a reception processing of the first signal from a handover destination base station before stopping a transmission processing via a channel for transmitting the third signal to the handover source base station when a handover is performed.

Description

  The present invention relates to a mobile station in a wireless 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 a QPSK modulation method and a 16-value QAM method according to the radio environment between a base station and a 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 the mobile station when transmitting the result of whether data received from the base station via HS-PDSCH is acceptable or not as a response signal (ACK signal, NACK 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). The base station changes the downlink transmission format according to the received CQI information. In other words, when the CQI information indicates that the downlink radio environment is good, the transmission format is switched to a modulation scheme 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, the heads of P-CCPCH and HS-SCCH frames coincide with the heads of CPICH frames. Where HS-PDSCH
The beginning of the frame is delayed by 2 slots with respect to HS-SCCH, etc., but the mobile station
This is because it is possible to demodulate the HS-PDSCH using a demodulation method corresponding to the received modulation type after receiving the modulation type information via the S-SCCH. HS-SC
CH 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.

It is assumed that the mobile station moves from the wireless zone 1 (cell 1) toward the wireless zone (cell 2), and performs a process of switching the wireless zone from 1 to 2 as it moves.

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.

Another object of the present invention is to maintain an adaptive modulation control procedure during 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.

  In the present invention, a first signal indicating a transmission format of data transmitted from the base station is received, and a second signal including the data transmitted from the base station in response to the first signal is received. In the mobile station that transmits the third signal to the base station in response to the second signal, the transmission process via the channel that transmits the third signal to the base station that is the handover source is stopped when performing a handover. Before starting, a mobile station comprising a control unit for starting reception processing of the first signal from the base station of the handover destination is used.

According to the present invention, it is possible to provide a radio communication system, a radio base station, and a mobile station in consideration of handover.

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

  In addition, the procedure of adaptive modulation control is easily maintained during handover.

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 a figure for demonstrating the operation | movement (with frame shift | offset | difference) at the time of the handover which concerns on this invention.

  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 second data (for example, the second channel) transmitted by the mobile station in response to reception of the first data (for example, CPICH transmitted via the first channel) transmitted from the radio base station. The second wireless communication apparatus receives the third data transmitted from the wireless base station (for example, HS-SCCH transmitted via the third channel) according to the CQI information transmitted via In this case, at the time of handover, the reception channel for the first data is switched first with respect to the switching of the reception channel for the third data.

As a result, the first data is switched as soon as possible after the reception channel is switched for the third data.
This data can be reflected.

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

Of course, the present invention can be applied not only to HSDPA but also to other wireless communication systems that perform handover processing. At that time, it is most preferable to apply to a system that performs adaptive modulation control (further, retransmission control, etc.) 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.

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 the mobile station moves, it is possible to continue communication with other communication apparatuses by switching the radio 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), and 16 transmits and receives radio signals to and from the mobile station 7. The radio | wireless transmission / reception part for performing is shown.

Reference numeral 17 denotes data that is transmitted to the mobile station 7 to store retransmission data for retransmission in order to perform retransmission control by H-ARQ described above, or to transmit using HS-PDSCH, which is a shared channel. A storage unit for storing data waiting for transmission order 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, and a transfer processing unit 24.

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).

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

  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

Therefore, the retransmission management unit 21 reads out the MAC-hs PDU that has failed to be transmitted from the storage unit 17, gives it again to the downlink signal processing unit 19, and causes 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 provides the 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 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 shown in FIG. 5, but a plurality of (three in this case) wireless transmission / reception processing units 16 and control units 18 are provided for each wireless area (cell). Data received from the interface unit 15 is distributed to the corresponding control units 181 to 183, and the control unit 1
81 to 183 execute processing corresponding 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 handover processing function 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).
While the mobile station 7 is receiving the HSDPA service, the mobile station 7 is connected via the HS-DPCCH.
CQI information for adaptive modulation control is periodically fed back to the base station. 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 an error presence / absence notification from the HS-PDSCH processing unit 36, the HS-DPCCH processing unit 37 transmits a reception result 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 handover processing function unit 39 controls the operation of each unit during handover. Details of the operation control will be described later.

Therefore, the mobile station 7 checks the HS-SCCH every subframe, and when it is notified that data transmission via the HS-PDSCH is performed to the mobile station 7, 1 of the HS-PDSCH after two slots. By receiving the subframe, demodulating and decoding (turbo decoding),
The decoding result is obtained, and whether or not reception is possible is determined by CRC calculation using CRC bits.
The received data is stored in the storage unit 32 and a NACK signal is transmitted to the radio base station 6 via the HS-DPCCH.

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 a description of the configuration and operation of each device. The operation during handover will be described in detail below.
・ Operation during handover
(A) “CQI information transmission destination switching timing”
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, CPI) transmitted from the radio base station 61.
Second channel (for example, CQI information) generated based on the reception quality (for example, reception SIR) received by CPICH processing unit 34 (see the black portion of CPICH in FIG. 8). ) Is transmitted to the radio base station 61 by the HS-DPCCH processing unit 37 (refer to CQI information transmitted one slot after completion of reception of the blacked portion).

The radio base station 61 transmits third data (for example, refer to the HS-SCCH of the fifth subframe) and the corresponding HS-PDSCH subframe according to the second data,
The mobile station 7 completes one cycle of data transmission by transmitting an ACK signal (with no reception error) at the timing included in the ninth subframe, as described in FIG. When a handover occurs in the middle, a data portion that causes trouble including data included in this cycle is generated (see data surrounded by a dotted frame in FIG. 2).

However, in FIG. 8, the control unit 33 (handover processing function unit 39) of the mobile station 7
Is HS-SCC at timing C1 (between the sixth and seventh subframes) in the figure.
The channel for receiving H is switched (switching from the radio base station 61 to 62), but at least before that (timing A1, A2 or the head of any slot between them), the CPICH reception channel The CPICH processing unit 34 is controlled to perform switching (switching from the radio base station 61 to 62).

For example, at timing A1 (about 0.5 slot of the third subframe), CPIC
Assuming that channel switching of H is performed, 3 from the 0.5th slot of the third subframe.
The data is received in the radio zone (cell 2) formed by the handover destination radio base station 62 over the slot period.

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 handover processing function unit 39 switches the transmission source for CPICH reception at timing A2, the CQI information and the tenth information transmitted at timing B2 in FIG.
Corresponding HS-SCCH transmitted in subframe, HS-PDSCH with 2 slot delay
Similarly, the ACK signal transmitted at the timing within the 14th subframe is similarly free from trouble, so that at least one data transmission cycle is 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).

The above is the explanation of the device switching timing of the CPICH (receive quality measurement channel) as the first data, but the CQI information (second data)
The switching timing of the transmission destination of the parameters used for the adaptive modulation control will be described with reference to FIG.
(B) “CQI information transmission destination switching timing”
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 depends on the CPICH reception quality (reception SIR) received from the switched radio base station 62. Although the selected CQI information is transmitted, the transmission destination is preferably a timing B1 that is a transmission timing of reception quality measured in a measurement period starting from the timing A1 (after the timing A1 and before the timings C1 and C2. It is preferable to switch at the timing.

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). Since the transfer processing unit 24 is provided as shown in FIG. 5, the CQI information received from the mobile station 7 is transferred to the radio base station 62 by the transfer processing unit 24.

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.

Finally, regarding the transmission timing of the ACK (NACK) signal, the transmission destination may be switched at D which is the transmission timing of the first ACK transmitted after C1.

As described above, in this embodiment, for example, the switching timing of the CPICH reception channel (to the handover destination), the switching timing of the transmission destination of CQI information (to the handover destination), and the (handover of the HS-SCCH reception channel) Switching is performed in the order of switching timing to the destination and switching timing of the transmission destination of the HS-DPCCH, which is described as a preferred mode.

Preferably, the switching timing of the transmission source for CPICH reception is the earliest among the channels that need to be switched due to handover (within the specified channels).

This is because the handover-destination radio base station is considered to be a channel that needs to be received in order to generate data that the earliest acquisition is desired.

Therefore, if it is considered that the channel needs to be received in order to generate the data that the handover destination radio base station desires to acquire earliest by the radio system, the channel may be switched first. it can.

In the above-described embodiment, an example in which HS-SCCH and HS-PDSCH are continuously allocated to one mobile station 7 has been described. However, since the channel is a common channel, it may be allocated 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 that is subordinate to the drift RNC and is 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, a handover between different radio base stations (especially a handover to a different frequency) and a handover to a radio base station under a different RNC (especially a handover at a different frequency) 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-SCCH reception channel, the HS-SCCH transmission start timing C1 that is first received from the handover destination radio base station 6 is determined from the beginning of the subframe 7. Consider that the delay is G.

That is, if the transmission timing of CQI information required for generating the HS-SCCH transmitted at timing C1 is matched with the handover destination radio base station 6, if CQI information is transmitted at timing B as shown in the figure, It will be good.

If the reception quality measurement period for generating CQI information is a period (for example, from 3 slots before to 1 slot before) determined based on the transmission start timing of CQI information, CP
It is desirable to compensate for the ICH frame shift G by starting measurement at timing A2 delayed by G with respect to timing A1 as shown in the figure.

For the first subframe received after switching the transmission source for HS-SCCH reception,
This is because fairness can be maintained because the result of measurement (measured at the same timing as other mobile stations in the handover destination radio base station 6) is reflected at the timing in accordance with the handover destination radio base station 6.

Further, regarding the period G, it is preferable to apply to the switching time, but the timing A1.
Can be switched immediately, or can be switched immediately at timing A2.

Similarly, the transmission destination of the ACK signal is switched at timing B (or timing until transmission of the first ACK signal to be transmitted after timing B), thereby enabling HS-PDSC.
It is desirable to switch the entire CH at once from the viewpoint of facilitating channel switching control.

However, as shown in the figure, the problem that the ACK signal (ACK signal indicated by an arrow as a problem) does not reach the radio base station 6 at the handover source is allowed.

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 30 Wireless 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 Handover processing function unit

Claims (3)

Receiving a first signal indicating a transmission format of data transmitted from the base station, receiving a second signal including the data transmitted from the base station according to the first signal, and receiving the second signal In a mobile station that transmits a third signal to the base station according to the signal of
Control for starting the reception process of the first signal from the handover destination base station before stopping the transmission process via the channel for transmitting the third signal to the handover source base station at the time of handover And a mobile station.   The mobile station according to claim 1, wherein the third signal indicates a reception result of the second signal.   The mobile station according to claim 1, wherein the first signal is transmitted / received via a shared channel.

Images