KR100993712B1 - Communication system, and transmission method - Google Patents

Abstract

In the DHO city, the DHO implementation encodes the data to be transmitted, interleaves, divides the data into segment data, and sends the data to each transmission path. When data is received, the segment data is received from each transmission path, combined, deinterleaved, and decoded to receive the data. In the case of segmentation into segment data, segment data having a larger data amount is allocated to a transmission path having good transmission quality, and a segment having a lower data amount is allocated to a transmission path having a lower transmission path quality depending on the transmission path quality. .

Transmission path, segment, DHO silencing, distribution rate, interleaving, handover, subcarrier

Description

Communication system, transmission method {COMMUNICATION SYSTEM, AND TRANSMISSION METHOD}

The present invention relates to a communication system and a transmission method, and is particularly suitable for use in a mobile communication system according to the CDMA system.

Diversity HandOver (DHO) between base stations (BTS) in a 3GPP system is realized by selective synthesis / replication distribution in a mobile terminal (UE) / base station control device (RNC). That is, two or more wireless transmission paths transmit and receive the same data, and select the ones having good transmission path quality (the data arrived without error).

1 is an image diagram of a DHO between base stations.

The mobile terminal UE communicates with the plurality of base station Node Bs through the plurality of radio line Uu, and these base station Node Bs communicate with the base station controller RNC through the communication line Iub. In the case of DHO, the same data is sent from each base station Node B to the base station Node B, and the same data is sent from one base station Node B to one mobile terminal UE. The mobile terminal UE despreads the same data sent from each base station Node B, synthesizes them, obtains demodulated data, and performs error correction decoding processing again to reproduce transmission data. When the mobile terminal UE moves from the management of any base station Node B to the management of another base station Node B, by selecting and receiving data from a circuit having good transmission quality, the data from the distant base station Node B is not used naturally. Since data from the approaching Node B is selected, instantaneous seamless handover can be realized.

However, in the case of DHO in the 3GPP system, in order to transmit the same data to a plurality of transmission paths, a decrease in radio capacity occurs with the increase of the transmission paths.

FIG. 2 is a diagram for explaining the flow of data during DHO in 3GPP when there are two radio transmission paths.

Information data that was initially one is copied and assigned to two radio transmission paths. CRC bits are added to the information data, turbo coded, and terminal bits which are redundant bits are added. Then, the first interleaving process is performed, and the interleaved data is divided into two data, for example. Then, after rate matching, the second interleave processing is performed, the data is divided into slots and loaded on a radio frame.

In this way, since the information data is copied and transmitted from the base station control device to the base station, the line between the base station and the base station control device is unnecessarily used, and the wireless line from the base station to the mobile terminal is also unnecessary.

In addition, although each of the radio transmission paths is separated by different spread codes, a separate radio transmission path becomes noise in performing despreading on any radio transmission path, so that an increase in power for securing a desired SIR occurs. do.

3 is a diagram illustrating deterioration of SIR.

In a CDMA communication system, since data is transmitted using a single carrier, data in a spread state of different radio transmission paths are transmitted so as to overlap in the same frequency band. In the mobile terminal, the signal of one wireless transmission path is obtained by despreading, but the data of the other wireless transmission path is received in a state where it is spread, resulting in noise with respect to the data of the despread wireless transmission path. Therefore, the more wireless transmission paths are used, the more this noise becomes.

Patent Literature 1 discloses a handoff means that has a cell diversity effect without instantaneous interruption of communication and that the amount of downlink radio resource usage of the radio base station does not change during non-handoff and handoff.

Patent Document 1: Japanese Patent Application Laid-Open No. 2000-217139

<Start of invention>

An object of the present invention is to provide a communication system employing a soft handover method that can save radio resources and can maintain a good transmission quality when a mobile terminal receives data.

The communication system of the present invention includes error correction encoding means for error correction encoding data to be transmitted, interleaving means for interleaving the error correction encoded data, dividing means for dividing the interleaved data, and the divided data. And transmitting means for transmitting from the different wireless devices, respectively.

1 is an image diagram of a DHO between base stations.

Fig. 2 is a diagram for explaining the flow of data at the time of DHO in 3GPP when there are two radio transmission paths.

3 is a diagram illustrating deterioration of SIR.

4 illustrates the advantages of OFDM.

Fig. 5 is a block diagram showing the conceptual configuration of a DHO embodiment of the embodiment of the present invention.

Fig. 6 is a diagram showing the conceptual configuration of a DHO processing unit provided on the base station or the radio network side according to the embodiment of the present invention.

Fig. 7 is a diagram showing a state of processing for receiving data when the OFCDM method is used according to the embodiment of the present invention.

8 is a diagram for explaining an example of a method of combining segmented data (No. 1).

9 is a view for explaining an example of a method of combining segmented data (No. 2).

10 is a diagram for explaining an example of a method of combining segmented data (No. 3).

11 illustrates another example of a method of combining segmented data.

12 is a diagram illustrating a flow of data of retransmission processing.

It is a figure which shows the example at the time of applying embodiment of this invention to 3GPP.

14 is a flowchart (part 1) of a DHO unit according to the embodiment of the present invention.

15 is a flowchart (part 2) of a DHO unit according to the embodiment of the present invention.

16 is a flowchart (part 3) of a DHO unit according to the embodiment of the present invention.

17 is a flowchart (part 4) of a DHO unit according to the embodiment of the present invention.

18 is a diagram for explaining still another embodiment of the present invention.

19 is a diagram illustrating an example of a data distribution ratio determination method.

20 is a view for explaining another example of the data distribution ratio determination method.

21 is a diagram illustrating a concept of mode switching.

22 is a motion image diagram of change in distribution ratio.

Fig. 23 is a diagram showing the state of allocation of distribution values to a transmission path to be deleted.

24 is a diagram illustrating a data division ratio determination method.

25 is a flowchart (part 1) of a processing example of distribution ratio calculation.

26 is a flowchart (part 2) of a processing example of distribution ratio calculation.

Fig. 27 is a diagram showing a determination example when the number of times of data reception supplied as the measurement period is ten.

28 is a processing flow (part 1) according to another example of the distribution ratio calculation method.

29 is a processing flow (part 2) according to another example of the distribution ratio calculation method.

BEST MODE FOR CARRYING OUT THE INVENTION [

Embodiment of this invention makes it possible to reduce the influence of frequency selective fading by using the subcarrier in OFDM system as a preferable best form.

In recent years, OFCDM has attracted attention as the next communication system.

The Orthogonal Frequency and Code Division Multiplexing (OFCDM) scheme is an Orthogonal Frequency Division Multiplexing (OFDM) scheme in which data is transmitted in parallel using a plurality of subcarriers. It is aimed at multiplying users.

OFDM itself has the following advantages.

Strong against narrowband interference

Strong against frequency selective fading

High frequency utilization efficiency (since frequency sharing between subcarriers is possible)

Frequency domain processing possible

4 is a diagram for explaining the advantages of OFDM.

As shown in Fig. 4, in normal CDMA, data is transmitted using a single carrier, and in OFDM, data is transmitted using a plurality of orthogonal subcarriers. Since OFDM transmits using a plurality of subcarriers, even if frequency selective fading occurs, only arbitrary subcarriers are affected. In addition, in the affected subcarriers, it is possible to regard frequency selective fading as flat fading (simple attenuation), and since the desired SIR of only the subcarriers affected by frequency selective fading becomes low, the power of each subcarrier is reduced. By performing the control, this frequency selective fading problem can be avoided.

On the other hand, in the case of a single carrier, when frequency selective fading occurs, the entire transmission carrier is affected, so that the entire transmission data is affected. In addition, even if this is to be improved by power control, it is difficult to improve the frequency band affected by the frequency selective fading, so that it is difficult to lead to the improvement of the bit error rate.

In a system for performing wireless transmission using subcarriers such as OFDM, wireless transmission on a subcarrier basis is more likely to be guaranteed compared to wireless transmission using a single carrier.

In the present system, since it is a single carrier system, the same data is transmitted to all transmission paths in the DHO, and the mobile station aims at the diversity effect by combining these data.

Therefore, in the following embodiment, the OFCDM method is preferably employed, but the CDMA method and the OFDM method may be used as the radio method.

In the embodiment of the present invention, when a radio transmission path is added in the DHO city, the data is divided into channels according to the number of radio transmission paths without transmitting the same data (for example, if there are N radio transmission paths). N-split), and the divided data is transmitted using the respective radio transmission paths. By dividing the data and transmitting the data using each of the wireless transmission paths, the amount of data transmitted in one transmission path is reduced, so that the extent to which the other transmission paths become noise for a specific transmission path can be reduced.

Preferably, each radio transmission path is transmitted from a different radio base station.

Here, the transmission target data is interleaved before being divided into a plurality of radio transmission paths. This eliminates and averages the quality bias between transmission paths.

Fig. 5 is a block diagram showing the conceptual configuration of the DHO embodiment of the embodiment of the present invention.

The DHO implementation section 10 is provided with an Interleave / De-Interleave section 12 that performs Interleave / De-Interleave processing, and a Segmentation / Reassemble section 13 that performs Segmentation / Reassemble processing. The data encoded by the Coding / Decoding section 11 is interleaved in the Interleave / De-Interleave section 12, divided by the Segmentation / Reassemble section 13 for each radio transmission, and transmitted to each radio transmission path. . The divided data received from each radio transmission path is merged in the segmentation / reassemble unit 13, deinterleaved in the interleave / de-interleave unit 12, and decoded in the coding / decoding unit 11, Is received.

The DHO implementation section 10 is provided in the mobile terminal, and also in the base station control apparatus to control each DHO.

6 is a diagram showing the conceptual configuration of a DHO processing unit provided on the base station or the radio network side according to the embodiment of the present invention.

The DHO processing unit 15 performs the following processing. The DHO processing unit 15 may exist at a place other than the RNC in the 3GPP system (for example, a host device of the RNC, a base station, and the like).

(1) Error correction coding process after CRC is assigned to data to be transmitted.

(2) After performing the processing in (1), interleaving processing

(3) Divide the data processed in (2) into one or more segments and transmit them to the base station

(4) Rate matching processing such as punctures (optional)

The base station transmits the data received from the DHO processing unit 15 in the radio section.

Here, preferably, one base station uses the first spreading code already used before the handover as it is, and the other base station transmits using the second spreading code specified at the start of the handover. . Of course, it is preferable that the frequencies used by one base station and the other base station are the same.

Therefore, at the time of handover, the base station before the handover does not need to add and transmit a spreading code, and the increase in the number of spreading codes occupied by one mobile station at the time of handover can be suppressed.

In FIG. 6, the second rate matching and the interleaving process are described, but the error correction coding process may be performed before the second rate matching.

The data reception processing of the radio section at the base station is performed, and the data transmitted to the DHO processing unit 15 is restored by the DHO processing unit 15 by performing a procedure opposite to that of the data transmission processing.

When the DHO processing unit is installed in the base station, each wireless base station obtains the encoded data by the same error correction encoding procedure (same turbo encoding process) for the same data received from the host apparatus (RNC) or the like. Interleave processing is performed with the same interleave pattern. The first radio base station extracts the first portion and the second radio base station performs rate matching and second interleaving processing on the interleaved data, and transmits the second portion.

Here, preferably, the 1st part and the 2nd part do not have overlap, and when both are combined, it is data used as data after an interleaving. In addition, a diversity effect can be obtained for important bit portions by setting overlapping portions in the first portion and the second portion (for example, by overlapping the tissue bit portions in the case of performing tissue encoding such as turbo encoding). have. FIG. 7 is a diagram showing a state of data reception processing in the case of using the OFCDM method according to the embodiment of the present invention.

First, as shown at the bottom of FIG. 7, reception of data for each subchannel in OFCDM is performed at each base station. At this time, it is assumed that an error occurs in the seventh sub-channel. A second deinterleaving process is performed on the data received in each of the two radio transmission paths to spread the error in the divided data. Next, data is sent from each base station to the base station control apparatus, and the data is combined. Then, in the base station control apparatus, the first deinterleaving process is performed, so that data errors are spread over the entire data. Then, an error correction decoding process is performed on the entire data, and the error is corrected.

Here, in order to combine the divided (segmented) data on the receiving side, the following method is considered.

(1) A join sequence is given to the segment data to be sent.

(2) The coupling sequence number is determined in the transmission path transmitted in advance by the transmitting and receiving side.

In the case of the combining method (1), a segment number is assigned when a segment is transmitted from the DHO execution unit (Tx: the base station control unit or the mobile terminal, and is transmitted to the radio transmitting unit from the circuit (sending side) for realizing the DHO method). do. For example, the number is stored as the split information in the header in the transmission format. Here, when two or more segments are transmitted in one transmission path, the data transmission method at that time is used, but for example, when multiple segments are transmitted, the header information also provides multiple information ( Ex: TB (Transport Block) multiple method on Iub (TS25.427) in 3GPP system).

Alternatively, in the wireless transmission unit, when the segment is transmitted as wireless data to the DHO implementation unit (Rx (receive side)), the DHO implementation unit uses a channel separate from the channel for transmitting the segment (as control information). There is also a method of notifying (Rx (receive side)) (Ex: DPDCH (segment transmission) and DPCCH (control information transmission) in a 3GPP system). At this time, when a plurality of segments are multiplexed and transmitted, multiple information is also given.

In the DHO implementation unit Rx, when combining the segments received from one or more radio transmission paths, the segments are combined in accordance with the divided number received at the same time.

The reason why a separate channel is used for a separate number during radio transmission is that in the embodiment of the present invention, the final transmission quality of each segment depends on the transmission quality obtained as a result of error correction after the segments are combined. . For example, apart from the embodiment of the present invention, even if error correction processing is separately performed for data transmission guarantee in each wireless transmission path, it is not necessarily required that each segment is error-free. . However, when wirelessly transmitting, it is preferable that control information such as pilot can be received even if a radio error occurs. Similarly, since this division number (also multiple information) requires high quality, it is required to be stored in a separate channel from the channel transmitting the segment or in a place managed separately for quality control. There is.

8 to 10 are diagrams for explaining an example of a method of combining segmented data.

As shown in Fig. 8, segments A to C are sent from the DHO implementation section Tx to the radio transmission section. At this time, the segmentation information of segment A is SN = A, the segmentation information of segment B is SN = B, and the segmentation information of segment C is SN = C. The DHO implementation section Rx receives the segments A to C from the radio transmission section and combines them based on the segmentation information.

9 illustrates the concept of transmitting segmentation information in a channel separate from the segment data. Segment data is transmitted to the data channel, and pilot signals, division numbers, and the like are transmitted as control information to the control channel in synchronization with this.

For example, it is preferable that this control information transmits the same data from a 1st base station and a 2nd base station, and acquires a diversity effect. This is because the division information (information necessary for the division data) such as the division number is important information for reproduction of the data. Therefore, each base station transmits combining order information of data transmitted from the first base station and data transmitted from the second base station.

Of course, by transmitting the combining order information 2 of the data which a 1st base station transmits from a 1st base station, and transmitting the combining order information 1 of the data which a 2nd base station transmits from a 2nd base station, It may be notified that the data is received from the second base station, followed by the data received from the first base station. Fig. 10 shows a case where the divided information is stored in a header or the like and transmitted as one radio frame. A data frame composed of a control region and a data region is transmitted to the transmission channel. Segment data is stored in the data area. In the control area, pilot signals, division numbers, and the like are stored as control information.

The combining method (2) is a method of determining in advance in which order the segments are to be combined with respect to the transmission paths for handover in the DHO implementation units on both the transmitting side and the receiving side. For example, when DHO is performed by three transmission paths, an identifier is set for the transmission paths, and the joining sequence numbers are associated with the identification numbers.

11 is a view for explaining another example of the method of combining segmented data.

The DHO implementation section Rx on the reception side transmits the association sequence assignment request to the DHO implementation section Tx on the transmission side. Then, the DHO execution unit Tx on the transmitting side assigns the association sequence number to each radio transmission path, and transmits this association sequence number to the DHO implementation unit Rx on the receiving side as the association sequence assignment response.

In addition, an ARQ function (data retransmission function) is implemented in the DHO implementation unit. For example, CRC is given to the divided data, and this is checked at the receiving side. In the case of NG, the identifier (combination number / sequence number, etc.) of the divided data is returned to the transmitting side. For the divided data indicated by NG, the DHO embodiment retransmits the target divided data, where the retransmission is attempted using the transmission path having the best quality.

For example, when DHO is performed in two transmission paths, when the reception side receives a non-receipt notification on the reception side for the divided data transmitted in transmission path # 1, the destination is transferred to the other transmission path # 0. Resend the divided data.

12 is a diagram illustrating a flow of data of a retransmission process.

In FIG. 12, segment # 0 is transmitted using transmission path # 0 and segment # 1 is transmitted using transmission path # 1 from DHO implementation part Tx on the transmission side. The DHO implementation section Rx on the receiving side checks the CRC attached to the segment data. Here, the CRC of segment # 0 is OK, and the CRC of segment # 1 is NG. Therefore, the DHO implementation section Rx on the receiving side requests retransmission of segment # 1 to the DHO implementation section Tx on the transmission side. The DHO implementation section Tx on the transmission side detects that the transmission quality of the transmission path # 0 is better, and transmits the segment # 1 to the DHO implementation section Rx on the reception side using the transmission path # 0.

It is a figure which shows the example at the time of applying embodiment of this invention to 3GPP.

In the 3GPP system, the segment processing shown in the figure is performed by the DHO processing unit during the processing performed by the base station. Thereafter, each segment is a TB (Transport Block), and transmitted to the base station in a form in which Iub-FP format processing has been performed.

FIG. 13 shows a state where TB # 0 and TB # 1 are transmitted to base station # 0 and TB # 2 is transmitted to base station # 1 among the divided data.

By applying as mentioned above, it becomes possible to apply embodiment of this invention also on a 3GPP system. In addition, the same method as the above-described method can be adopted for the spreading code at the time of transmission.

From the necessity of assembling the divided data on the receiving side, it is necessary to notify the receiving side of the information necessary for assembling. As suggested in the text, there is a case of negotiating in advance or giving to the transmission data.

14-17 is a flowchart of the DHO part which concerns on embodiment of this invention.

The basic flow is a method of negotiating in advance. In contrast, in the method of attaching to the transmission data, the assembling order is determined based on the DHO state, the number thereof, and the like, and this information is notified to the counterpart along with the data transmission.

In the case of negotiation in advance, this is achieved by defining an assembly sequence in each transmission path. In the case of in-band notification, the receiving side assembles in order by the identifier (assembly number, etc.) obtained when data is received from each transmission line.

The assembly number used at the time of assembly is a value which changes according to a DHO state. That is, in the case where the soft handover (frequency is the same before and after the handover) is maintained, the number of branches (number of transmission paths) may change depending on the radio wave condition. For this reason, the following is performed.

How to determine by advance negotiation:

Whenever the DHO state changes, the assembling order (assembly ordering to each transmission path) is determined at the transmitting side and the receiving side (negotiation is performed: switching timing is specified).

How to notify inband:

Regardless of the DHO status, the sender decides uniquely. In order to be able to detect the loss of a segment, the last segment can be identified.

Fig. 14 is a flowchart on the transmitting side in the case where the assembly sequence of segment data is negotiated with the receiving side in advance.

In step S10, it is determined whether the DHO state has changed. If the judgment of step S10 is no, the process proceeds to step S12. If the determination of step S10 is YES, then negotiation is performed with the receiving side in step S11, and the processing proceeds to step S12. In step S12, the transmission data is received, and in step S13, the CRC is given to the received transmission data. In step S14, the encoding process is performed. In step S15, the interleaving process is performed. In step S16, it is determined whether or not the DHO is being performed. If the determination of step S16 is no, the process proceeds to step S18. If the judgment of step S16 is YES, the division process is performed in step S17, and the flow proceeds to step S18. In step S18, the data is transmitted, and the flow returns to step S10.

15 is a flowchart on the transmission side in the case of giving the assembling sequence of the segment data to the transmission data.

In step S20, transmission data is received. In step S21, a CRC is given to the received transmission data. In step S22, the encoding process is performed, and in step S23, the interleaving process is performed. In step S24, it is determined whether it is in the state which is performing DHO. If the judgment of step S24 is no, the process proceeds to step S27. If the judgment of step S24 is YES, it is determined in step S25 whether or not the first transmission data after the DHO is transmitted. If the determination of step S25 is no, the process proceeds to step S27. If the judgment of step S25 is YES, the assembly number is set in step S26, and the division process is performed in step S27. In step S28, it is determined whether there is a change in the number of branches (the number of wireless transmission paths). If the judgment at step S28 is no, the process proceeds to step S30. If the judgment of step S28 is no, the process proceeds to step S30. If the determination of step S28 is YES, the assembly number is changed in step S29, the assembly number is assigned to the divided transmission data in step S30, the transmission data is transmitted in step S31, and the flow goes to step S20. Go back.

Fig. 16 is a flowchart on the receiving side when the assembly sequence of segment data is negotiated with the receiving side in advance.

In step S35, it is determined whether the assembly cycle has expired (all data to be assembled has been received). If the determination of step S35 is no, step S35 is repeated. If the judgment of step S35 is YES, the data is assembled in step S36 in accordance with a predetermined assembly order. In step S37, the data is transferred to the next processing unit, and the flow returns to step S35.

Fig. 17 is a flowchart on the receiving side in the case of giving the assembling sequence of the segment data to the transmission data.

In step S40, it is determined whether the assembly cycle has expired (or all the assembly data has been received). If the determination in step S40 is no, step S40 is repeated. If the determination in step S40 is YES, the data is assembled in step S41 according to the assembling sequence obtained at the time of data reception. In step S42, the data is transferred to the next processing unit, and the flow returns to step S40.

By the assembling procedure, it is possible to detect the loss of the segment. The occurrence of segment deficiency is notified to post-processing, and, in some cases, segment retransmission is prompted. Here, for example, it is conceivable to use a technique disclosed by HSDPA as the retransmission method / procedure.

Therefore, it is also possible to notify the sending side DHO of the segment retransmission request, and to resend using the transmission path determined to be the best wireless transmission path. Like the HSDPA technology, the wireless transmission of the segment transmitted from the transmitting side DHO part is performed. The responsive control may be realized by a functioning unit in charge.

When the retransmission request is received by the transmitting-side DHO unit, when retransmitting, only the segment is regarded as a transmission target, and it is possible to segment and transmit the segmentation again to a plurality of transmission paths instead of a single transmission path.

According to the said embodiment, the following effects can be anticipated.

(1) The total data transmission amount by the DHO can be suppressed.

(2) Power increase by DHO can be suppressed. This is because with the addition of the radio transmission path, the amount of transmission data in each radio transmission path is reduced (data transmission with a high spreading rate is possible).

(3) By the power suppression by (2), an increase in radio capacity can be expected.

In the above embodiment, in the case of a state having a plurality of radio transmission paths (DHO state), it is proposed that the data is divided and transmitted to each radio transmission path without transmitting the same data. It is assumed that OFCDM is applied to the radio system, and it is possible to avoid the influence of frequency selective fading, which is a characteristic of the OFDM system. In other words, it is based on the fact that the same data is transmitted using different radio transmission paths, so that diversity effects do not have to be expected.

In the following, as another embodiment of the present invention, it is proposed to perform data segmentation in consideration of transmission path quality in each wireless transmission path.

Specifically, the wireless transmission / reception unit (base station) transmits the quality information (in the downward direction) to the DHO processing unit (RNC: base station control device). Alternatively, quality information is transmitted from the mobile terminal (wireless transceiver) to the mobile terminal (DHO processor) in a wireless transmission path (upward direction).

The DHO processing unit determines the amount of data (a ratio of dividing data) to be transmitted to each radio transmission path based on the radio transmission path quality information, and transmits the divided data. In the above-mentioned embodiment, although the data is divided equally, by changing the ratio of dividing the data, more data is sent to one transmission path and less data is sent to the other transmission path. In addition, although it is the same in embodiment mentioned above, below, although the case where the number of transmission paths is two is demonstrated as an example, what is the number of transmission paths may be sufficient.

18 is a diagram for explaining another embodiment of the present invention.

When the wireless transmission / reception units # 0 and # 1 receive the wireless transmission path quality information # 0 and # 1, respectively, they are inputted to the data division rate determination unit 20. The data division ratio determination unit 20 calculates a division ratio and inputs it to the data division / transmission unit 21. The data division / transmitter 21 receiving the transmission data from the data reception unit 22 divides the data based on the obtained division ratio, and sends divided data # 0 and # 1 to the wireless transceivers # 0 and # 1, respectively. , Send it. In the example here, the radio transceivers # 0 and # 1 are provided in the base station BTS, and the data division ratio determination unit 20, the data division / transmission unit 21, and the data reception unit 22 are connected to the base station controller RNC. It is installed.

In addition, the DHO process of embodiment mentioned above shall be performed by the data division / transmitter 21. FIG.

Control information used in inner loop power control performed between a base station and a mobile device, as used in International Application No. PCT / JP03 / 11270 or Japanese Patent Application No. 2004-571830, for a method of acquiring wireless transmission path quality information. It is conceivable to use Transmission Power Control (TPC). In this embodiment, the data distribution rate to be transmitted from the TPC acquired from each transmission path is determined.

The mobile unit instructs the base station to increase or decrease the transmission power by the inner loop power control. The increase / decrease instruction of the transmission power indicates the radio situation itself at that time. Therefore, the data distribution ratio determination unit in the RNC acquires the TPC information from the BTS for all transmission paths.

The data distribution rate determination unit 20 which has received the TPC information of each transmission path from each base station (BTS) measures this for a predetermined time and, from the result, determines the data distribution rate to be transmitted to each transmission path (that is, each base station BTS). The data is calculated and notified to the data division / transmitter 21.

The data division / transmitter 21 transmits data to each base station in accordance with the data distribution ratio notified from the data distribution ratio determination unit 20.

The data distribution ratio determination unit 20 determines the data distribution ratio from the TPC information in the measurement period section. It is assumed that the TPC used here is either the transmit power UP instruction or the down instruction, which is used in the current 3GPP system.

Specifically, the number of the TPC information collected for a certain period of time indicating the power reduction instruction is accumulated. At the end of the measurement period, the ratio of the integrated values in each BTS is taken as the distribution ratio.

19 is a diagram illustrating an example of a data distribution ratio determination method.

In the example of Fig. 19, the power increase instruction, x is a decrease instruction, and 4 is the BTS # 0 and 8 is the BTS # 1, so the distribution ratio is BTS # 0: BTS # 1 = 1: 2.

As another data distribution ratio determination method, a method in which the distribution ratio is a value obtained by multiplying the data distribution ratio at the present time with respect to the integrated value calculated at the end of the measurement period is considered.

20 is a diagram illustrating another example of the data distribution ratio determination method.

In the example of FIG. 20, since ○ is the power increase instruction and × is the decrease instruction, the integrated value of BTS # 0 is 4, the data distribution ratio is 2, the integrated value of BTS # 1 is 8, and the data distribution ratio is 1, The distribution ratio is BTS # 0: BTS # 1 = 1: 1.

As mentioned above, the data distribution ratio determination part 20 needs to know the distribution ratio at the present time. The previous value may be stored in the data distribution rate determination unit 20 or may be notified by the data division / transmitter 21.

The distribution ratio calculated by the data distribution ratio determination unit 20 described above is considered to be corrected in some cases. The following is considered as a correction method.

(1) A certain amount is increased in the transmission line with a large current distribution ratio.

(2) Increase a certain amount of transmission path with a small current distribution ratio.

(3) Correction is performed in accordance with the limitation of the division method in the data division / transmitter 21.

(4) Immediately after the handover, the initial value is supplied to the transmission path which does not have the current distribution rate (only in the case of the method of FIG. 20).

(5) Limit data distribution rate.

(6) When distribution is assigned to the deletion target transmission path at the time of data distribution after the transmission path deletion, it is preferentially assigned to the best transmission path.

First, in (1), for example, a transmission path with a large amount of transmission data is likely to have good radio quality, and therefore, the emphasis is placed on the transmission path that is considered to be good. The specific gravity method may be multiplied by a constant amount of coefficients, or may be realized by adding a constant amount.

Next, in (2), there is a possibility that the transmission path with a small amount of transmission data is just after the transmission path is added by handover, or the distribution ratio has dropped due to a temporary change in radio conditions. It is also conceivable to suppress (slow) the data distribution rate from tilting in a transmission path with a large amount of data.

The combination of (1) and (2) is also considered here. That is, when the distribution ratio finally calculated becomes an arbitrary value, it is switched to the mode of (1) or (2). 21 is a diagram illustrating the concept of mode switching, but in this manner, the threshold value for switching from mode 1 to mode 2 and the threshold value for switching from mode 2 to mode 1 at different distribution ratios. It is conceivable to construct a hysteresis.

Regarding (3), it is considered necessary because there is a limitation in the division method in the data division / transmission section 21. For example, as a method of dividing arbitrary data, 1/2, 1/4, 1/8,... In the case of taking a division method called, it is necessary to calculate a division ratio that can be generated by this division method. Therefore, rounding, rounding, etc. of the calculated value are performed.

For (4), immediately after the handover, since there is no previous value in the added transmission path, it does not have an initial value. For this reason, the ratio divided by the data division / transmitter 21 is notified and used.

For (5), a limit is set on the data distribution rate. For example, in a state where there are three transmission paths, when the minimum value of the split pattern is 1/10, even if the quality of any transmission path is very poor, 1/10 is assigned. This is because "the determination that no data is transmitted to any transmission path depends on the deletion of the transmission path by determining that the transmission path cannot obtain the DHO effect". The data distribution ratio determination unit 20 determines that the transmission path is capable of obtaining the DHO effect while the transmission path is present, and transmits divided data of the minimum unit even if the transmission path quality is in any deteriorated state. However, this depends largely on the minimum unit of data partitioning. For example, in a state in which the minimum division unit of data is 1/2 or the like, it may be considered that a transmission path without transmitting data at all may be provided without applying this.

Fig. 22 is an operational image diagram of the change in the distribution ratio, in which every transmission period obtains a transmission path state and calculates a distribution ratio to a base station BTS that transmits data to each transmission path. In FIG. 22, the ratio of BTS # 0, BTS # 1, and BTS # 2 changes with every measurement period.

In (6), if it is determined that the DHO effect cannot be obtained and the data transmission distribution is assigned to the transmission path to be deleted when the transmission path is deleted, this distribution is allocated to the transmission path having the best quality at the time of deleting the transmission path. Add a value.

Fig. 23 is a diagram showing the state of allocation of distribution values to the transfer path to be deleted. In period 1, BTS # 0 to # 2 transmit data, respectively, but in period 2, the transmission quality of BTS # 2 deteriorates, and the transmission path of BTS # 0 is the best transmission path. The BTS # 2 is deleted, and that much is allocated to the BTS # 0.

As a method of measuring the transmission quality, it is also conceivable to use the data quality of upstream data. However, in the FDD scheme, since the radio frequencies used in the upstream and the downlink are different from each other, the uplink radio quality information cannot be read in the same way as the downlink radio quality. The use of is possible. In the case of the OFDM method, since it is possible to suppress the influence of frequency selective fading, even if the FDD method is used, it is considered that the difference between the upstream and the downstream quality is unlikely to occur. I think there is no problem using.

In the case of the TDD system, since the frequencies used in the upstream and the downstream are the same, it is considered that the measurement can be performed with high accuracy even when the upstream data quality is used for the measurement of the transmission quality.

The upstream data can use BER (Bit Error Rate) and BLER (Block Error Rate) when performing error correction code / decoding for user data transmission / reception in the wireless section. In addition, using BER in radio control data also exists as an option.

However, in the DHO method of the embodiment of the present invention, the result of the error correction decoding on the user data is not necessarily good. That is, even if the data for which the error correction is not successful in each of the wireless transmission paths is correct, the final error correction result obtained by collecting data from all the wireless transmission paths is OK.

However, with regard to the radio control data, since it is necessary to be able to receive control data normally in each radio transmission path, a method of using the quality information for this control data will be described.

Means for notifying the quality of radio control data from the BTS to the RNC also exist in 3GPP. In 3GPP, an area (QE) for storing quality information exists in the data transmission frame format between the BTS and the RNC. This QE stores the quality (Transport Channel BER) obtained as a result of error correction of the user data at the time of user data transmission, and the quality (Physical Channel BER) of control data when there is no user data. Which of these can be selected can be selected by the QE Selector. Therefore, when the present invention is applied to 3GPP, the QE Selector is set to "non-Selected" (Physical Channel BER is selected).

In the transport channel BER, the TTI period of the TrCH is a measurement section. The reported TrCH BER measurement is an average value of BER in the measurement section, and the measurement target is DPDCH.

In addition, for the physical channel BER, the TTI period of the TrCH becomes the measurement interval, and this is when the Phy BER is enabled through the C-Plane IE "QE-Selector" shown in TS25.433. The measurement of the reported phy BER is the average value of BER in the measurement section, and the measurement target is DPCCH.

The data partition rate determination method is the same as in the case of using the TPC. In the case of TPC, the ratio of the down information of the TPC in each transmission path was calculated. In the case of using the physical channel BER, the inverse of the data error rate is taken. Although FIG. 24 is a figure illustrating a data division rate determination method, in the case of FIG. 24A, the bit error rate BER is obtained for base stations BTS # 0 and # 1 of each transmission path, and is inversely proportional to the inverse thereof. We do with distribution ratio. FIG. 24B shows a method of multiplying the inverse of the bit error rate BER by the current distribution rate and making these ratios the new ratios.

Since the process of correcting the distribution ratio in the case of using BER is the same as in the case of using TPC, description thereof is omitted.

25 and 26 are flowcharts of examples of processes of calculating distribution ratios.

25 is a processing flow when TPC is used.

In step S45, a measurement period is set, and in step S46, downlink radio quality information is acquired for each transmission path. In step S47, it is determined whether the TPC is a decrease instruction. If the judgment of step S47 is no, the process proceeds to step S49. If the judgment of step S47 is YES, in step S48 1 is added to the count value for each previous transmission path, and the flow advances to step S49. In step S49, it is determined whether or not the measurement period has ended. If the determination of step S49 is no, the process proceeds to step S46. When the determination of step S49 is YES, the distribution ratio is calculated in step S50.

26 is a processing flow when BER is used.

In step S55, a measurement period is set, and in step S56, downlink radio quality information is obtained for each transmission path, in step S57, the current BER value is reflected in the previous BER value for each transmission path, and in step S58, the measurement is performed. Determine whether the cycle has expired. If the determination of step S58 is no, the flow proceeds to step S56. If the determination of step S58 is YES, then in step S59 the distribution ratio is calculated.

In the distribution ratio determination method of the above embodiment, the quality determination is performed for each of the data received within the period with the measurement period, but a method of weighting this determination is also considered.

For example, when the number of times of data reception is defined as the measurement period, the quality situation immediately before the end of the measurement is regarded as important when the measurement starts.

27 shows an example of the determination when the number of times of data reception supplied as the measurement period is ten.

In the example shown in Fig. 27, the weight is set so that the weight increases by 0.1 with increasing number of times (the weight to be set may be arbitrary. For example, the weight is set to a value that increases exponentially, The weight increase range may be 0 to 1 for TPC UP and 1 or more for TPC Down).

In addition, when the quality situation is OK (when the TPC goes down), it is set to 1 when the quality situation is NG (when the TPC goes up) (you may use BER or the like instead of TPC as the quality information). . For this value, the value obtained by multiplying the given weight is integrated for the measurement period. In the example of FIG. 27, as a result, the distribution ratios of BTS # 0 and BTS # 1 are 1: 4.

In addition, since the quality information acquired may also acquire the information equivalent to a measurement period in each transmission path at once, distribution ratio calculation is performed based on the information in that case.

28 and 29 are processing flows according to another example of the distribution ratio calculation method.

FIG. 28 is a flowchart for describing processing when the TPC is used for calculating the distribution ratio.

In step S65, a measurement period / initial weighting value is set. In step S66, downlink radio quality information is obtained for each transmission path. In step S67, it is determined whether the TPC is a decrease instruction. If the determination of step S67 is no, the process proceeds to step S70. If the judgment in step S67 is YES, then in step S68, the weighting value is multiplied by the value of "1" which is the addition value for each transmission path. In step S69, the value weighted to the previous addition value is added for each transmission path, and in step S70, the next weighting value is calculated. In step S71, it is determined whether the measurement period has expired. If the judgment of step S71 is no, the process proceeds to step S66. If the judgment in step S71 is YES, then in step S72 the distribution ratio is calculated.

Fig. 29 is a flowchart for explaining processing when the BER is used for calculating the distribution ratio.

In step S75, a measurement period / initial weighting value is set. In step S76, downlink radio quality information is obtained for each transmission path. In step S77, this time BER is weighted for each transmission path. In step S78, the current BER after weighting the previous BER value is reflected for each transmission path. In step S79, it is determined whether the measurement period has expired. If the judgment of step S79 is no, the flow returns to step S76. If the determination of step S79 is YES, then in step S80 the distribution ratio is calculated.

According to the above embodiment of the present invention, since transmission data distribution transmission according to the radio transmission path quality is performed, a lot of data flows through the transmission path with good quality, so that data communication with good efficiency according to the transmission path situation is possible.

In addition, since a poor quality transmission path takes a lot of radio resources, it may adversely affect other users as compared to the method of transmitting the same data as the DHO method applied to the current 3GPP system. There is no

Claims (18)

Error correction encoding means for error correction encoding data to be transmitted; Interleaving means for interleaving the error correction coded data; Dividing means for dividing the interleaved data; Transmitting means for transmitting the divided data from a wireless device through different wireless transmission paths, respectively And, And said dividing means determines the amount of data for allocating said divided data to each wireless transmission path based on the quality of said wireless transmission path. The method of claim 1, And a segmentation number indicating a sequence number of the segmented data when segmenting the data, and combining the segmented data on the receiving side with reference to the segmentation number. The method of claim 2, The division number is set in the header of the divided data. The method of claim 2, And the division number is set to control information transmitted in a channel separate from the channel for transmitting the divided data together with the divided data. The method of claim 1, When transmitting the divided data, the divided data is transmitted to the wireless device such that the order of combining the data is matched to the wireless device to which the data is transmitted and the order in which the divided data is combined is correct. Communication system. The method of claim 1, And a retransmission means for retransmitting the divided data which failed to be transmitted in response to a request from the receiving side by using a wireless device which has succeeded in transmitting. The method of claim 6, A wireless device used for transmission of retransmitted divided data is a wireless device having the best transmission quality. The method of claim 1, The divided data is transmitted from different wireless devices through different wireless transmission paths, and variable dividing means for varying a split ratio of data divided corresponding to each wireless device based on the transmission quality of the wireless device. Communication system characterized in that it further comprises. The method of claim 8, And said transmission quality is a transmission quality of a wireless device in the forward direction with respect to the direction in which the divided data is transmitted. 10. The method of claim 9, The transmission quality is obtained based on the TPC information from the receiving side. The method of claim 10, The calculation of the division ratio is performed by collecting power drop instruction information included in the TPC. The method of claim 8, And said transmission quality is a transmission quality of a wireless device in a reverse direction with respect to a direction in which divided data is transmitted. The method of claim 12, And said transmission quality is obtained based on the BER of the signal that the transmitting side receives from the receiving side. The method of claim 13, The calculation of the division ratio is performed by collecting the reciprocal of the BER. The method of claim 8, And in the case where the wireless device is deleted, assigning the split ratio assigned to the wireless device to be deleted to the wireless device having the best transmission quality. Error-correct encoding of the data to be sent, Interleaving the error correction coded data, Dividing the interleaved data, Transmitting the divided data from the wireless device through different wireless transmission paths, A data amount for allocating the divided data to each radio transmission path is determined based on the quality of the radio transmission path. The transmission method characterized by the above-mentioned. The method of claim 16, The divided data is transmitted from different wireless devices through different wireless transmission paths, and the splitting ratio of data divided corresponding to each wireless device is varied based on the transmission quality of the wireless device. Transmission method to do. Error correction encoding means for error correction encoding data to be transmitted; Interleaving means for interleaving the error correction coded data; Dividing means for dividing the interleaved data so as to have no overlapping part or overlapping part; Transmitting means for transmitting the divided data from each of the first and second wireless transmission paths used for soft handover And, And said dividing means determines the amount of data for allocating said divided data to each wireless transmission path based on the quality of said wireless transmission path.

Images