JP2001024556A - Communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a communication device capable of accurately detecting the transmission delay of each mobile station without exerting influence upon transmission capacity and the number of stored channels. SOLUTION: A receiving part 202 receives a signal obtained by multiplexing the signals of respective channels in the same frequency band through an antenna 201. A separation part 203 separates a part to be used for the calculation of a correlation value in the received signal. Correlation parts 204, 205 calculate the correlation values of the separated signal by respectively using 1st and 2nd basic codes to prepare respective delay profiles. When there is no propagation delay, a comparing/line estimation part 206 circulates individual delay profiles so that sections in which paths of channels to be detected appear coincide with each other and detects paths approximately coinciding with each other in respective circulated delay profiles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication device of a spread spectrum communication system, and more particularly to a communication device of a spread spectrum communication system for performing communication using a signal to which a midamble portion is added.

[0002]

2. Description of the Related Art Conventionally, there are the following spread spectrum communication systems that perform communication using a signal to which a midamble portion is added. Hereinafter, CDMA (Code Divisi) is used as a spread spectrum communication system.
An on-multiple access (on Multiple Access) method will be described as an example.

[0003] A base station in CDMA communication receives a signal in which signals of a plurality of channels are multiplexed in the same frequency band at the same time via a transmission line. This base station can extract signals transmitted from each channel (each mobile station) from a received signal by performing despreading processing using a spreading code assigned to each channel.

However, when the distance between each mobile station transmitting a signal of each channel and the base station is large, a delay occurs before the signal of each channel reaches the base station (hereinafter referred to as “propagation delay”). ) Will occur, and
If the distance between each mobile station and the base station is different, the propagation delay of each channel also varies.

Therefore, it is necessary for the base station to detect a propagation delay for each channel and to perform a despreading process at a timing in consideration of the detected propagation delay. Therefore, conventionally, in each mobile station, a signal added with a midamble portion created using a known basic code is transmitted, and in the base station, a signal transmitted by each mobile station is multiplexed with a received signal. , By performing a correlation value calculation process using the known basic code,
The propagation delay for each channel (each mobile station) is detected. Hereinafter, a method of detecting a propagation time using a midamble part in a conventional CDMA communication system will be described.

First, a signal transmitted by each mobile station (each channel) will be described with reference to FIG. 11 and FIG. FIG. 11 is a schematic diagram showing a procedure for creating a midamble pattern in a conventional CDMA communication system. FIG. 12 is a schematic diagram showing transmission timing of each mobile station in a conventional CDMA communication system. Here, a case where a midamble pattern for eight channels is created will be described.

As shown in FIG. 11, a pattern of a midamble portion (hereinafter, referred to as a “midamble pattern”) used for each channel is shown below using a basic code circulating at 456 (= 8 W) chip periods. Created according to the procedure. This basic code is known to the base station and includes eight blocks A to H having codes of different W (= 57) chip lengths.

First, as a first step, the phase of the basic code is shifted by {W × (n-1)} chips to the right in the figure. Here, W = 57 chips, and n is the number of channels. The phase to be shifted (the number of chips) is 0, W, 2W and 7W for channel 1, channel 2, channel 3 and channel 8, respectively.

As a second step, for each basic code shifted in phase, with respect to a certain block,
The remaining portion is deleted except for 456 chips from the leading end of this block. Here, the block A is used as a reference as an example.

As a third step, each code having a total length of 456 chips is circulated leftward in the figure by {W × (n-1)} chips. As a fourth step, the leading block of each code after the circulation is added to the end to form a 512-chip length code as a whole, and this code is used as a midamble pattern of each channel.

Next, as shown in FIG. 12, each mobile station transmits to the base station a transmission signal to which the midamble pattern of each channel created by the above procedure is added. That is, each mobile station transmits a transmission signal in which the midamble pattern of each mobile station is added to the midamble part between the data part 1 and the data part 2 at the same timing as the other mobile stations.

On the other hand, the base station receives a signal in which transmission signals transmitted from each mobile station are multiplexed in the same frequency band. FIG. 13 shows a correlation value calculation process performed by the base station using the received signal and the known basic code.
This will be described with reference to FIG. FIG. 13 shows the conventional C
FIG. 2 is a schematic diagram conceptually showing a situation in which a base station in a DMA communication system receives a transmission signal for each channel. FIG. 14 is a diagram illustrating an example of a delay profile obtained by a correlation value calculation process in a base station in a conventional CDMA communication system.

As described above, each mobile station and the base station are not only located at a distance from each other, but also the distances between each mobile station and the base station are different from each other.
There is a propagation delay before the signal transmitted by each mobile station reaches the base station, and the propagation delay varies for each signal transmitted by each mobile station. That is, mobile station 1, mobile station 2, mobile station 3, and mobile station 8
Are propagation delay 1, propagation delay 2, propagation delay 3 and propagation delay 8, respectively, until the signal transmitted from each of them reaches the base station. The signal received by the base station is a signal obtained by multiplexing the transmission signals from the respective mobile stations having the propagation delay shown in FIG.

As the correlation value calculation processing in the base station, first, out of the 512-chip reception signal received from the reference time 1303, only 456 chips are cut out from the terminal section 1302. Here, the reference time means that the leading end of each midamble part (for example, the leading end 1301 in the case of channel 1) in the signal transmitted by each mobile station is received by the base station when there is no propagation delay. It is time to be done.

Next, a correlation value between the cut-out received signal having a length of 456 chips and the above-mentioned known cyclic code is calculated. That is, based on the cyclic basic code shown in FIG. 14, the received signal having a length of 456 chips is multiplied by the basic code while shifting the phase by one chip, and a correlation value at each phase is calculated.

By such a correlation value calculation process, FIG.
The delay profile of each channel shown in FIG. At the time of calculating the correlation value as described above, when the code of the midamble portion from any of the mobile stations included in the received signal of 456 chips length matches the known basic code, the correlation value becomes It becomes maximum and a path having a certain size appears.

Therefore, the point in time when the value of each of the paths 1401, 1402, 1403, and 1404 in FIG.
The codes of the respective midambles from the mobile station 1, the mobile station 2, the mobile station 3, and the mobile station 8 included in the received signal of the chip length correspond to the time when the cyclic basic code in FIG.

Here, when there is no propagation delay of each mobile station, the point where the path corresponding to each mobile station becomes maximum is known. Therefore, the propagation delay that occurs before the signal actually transmitted from each mobile station reaches the base station is detected by referring to the point where the path corresponding to each mobile station has the maximum when there is no propagation delay. Is done.
For example, mobile station 1, mobile station 2, mobile station 3, and mobile station 8
Are respectively detected on a chip-by-chip basis as propagation delay 1, propagation delay 2, propagation delay 3, and propagation delay 8 shown in FIG. Propagation delay 1, propagation delay 2, propagation delay 3 and propagation delay 8 shown in FIG. 14 are obtained by expressing propagation delay 1, propagation delay 2, propagation delay 3 and propagation delay 8 shown in FIG. 13 on a delay profile, respectively. Things.

When the sum of the propagation delay and the delay dispersion of each mobile station is smaller than the W (= 57) chip length, the section in which a path having a certain size on the delay profile appears is determined by each mobile station. It is determined for each station. That is, in the above case, the paths corresponding to the mobile stations 1 to 8 are 1 to 8 in the delay profile shown in FIG.
In the W chip section (delay profile width).

By performing despreading processing using the data section at a timing considering the propagation delay of each mobile station detected as described above, interference removal demodulation of the data section is performed for each mobile station. It becomes possible.

[0021]

However, in the above-mentioned conventional CDMA communication system, when the cell radius is large, a signal transmitted from a mobile station located farther from the base station has a larger propagation delay. The sum of the signal propagation delay and delay dispersion may be larger than the W chip length. In this case, the path corresponding to the mobile station does not appear in the expected W chip section in the delay profile shown in FIG. 14, but appears in another W chip section. For example, in the case of the mobile station 1, the path corresponding to the mobile station 1 may appear in 2 to 8 W chip sections instead of the 1 W chip section shown in FIG.

Further, in the above case, when not only the desired wave of the signal transmitted from the mobile station but also a delayed wave is received by the base station, the mobile station transmits the mobile station to another W chip section in the delay profile. The path of the delayed wave appears in addition to the path of the desired wave corresponding to the station.

As a result, in the obtained delay profile, the path of the desired wave and the delayed wave of the mobile station does not appear in the expected W chip section, so that the detected propagation delay of the mobile station is inaccurate. Becomes Further, in the delay profile, since each path of the mobile station appears in a W chip section corresponding to another mobile station, each path of the mobile station is erroneously determined as a path of a desired wave and a delay wave of the other mobile station. May be detected. For this reason, the detected propagation delay of mobile stations other than the mobile station becomes inaccurate. Therefore, it is not possible to accurately detect the propagation delay of each mobile station, so that the interference removal demodulation characteristics deteriorate.

In order to solve the above problems, there is a method in which the mobile station performs control to adjust the transmission timing to compensate for the propagation delay. However, in order to realize this control, the base station needs to notify the mobile station at a precise timing of a control command for determining whether or not to execute this control. Therefore, when the delay dispersion is large in the base station, it is difficult for the base station to notify the mobile station of this control command at an accurate timing.

Even if the base station can notify this control command at an accurate timing, the base station needs to transmit this notification to the mobile station using the downlink, The transmission capacity of the user information on the line is reduced.

On the other hand, in order to solve the above problem, there is a method of extending W to increase the W chip section (delay profile width) of each mobile station in the delay profile. However, since the value obtained by dividing the midamble section by (accommodation channel + 1) corresponds to the delay profile width W of each mobile station, when W is extended,
If the midamble section length is fixed, the number of accommodated channels will decrease.

[0027] The present invention has been made in view of the above point, and a communication apparatus capable of accurately detecting the propagation delay of each mobile station (each channel) without affecting the transmission capacity and the number of accommodated channels. The purpose is to provide.

[0028]

A communication apparatus according to the present invention transmits a signal obtained by multiplexing, at the same time, two different reference codes unique to two different channels at the same time.

According to the present invention, a receiving apparatus that receives a signal in which two different known reference codes different from each other are multiplexed at the same time, performs a correlation value calculation process using the two known reference codes for each channel. By creating two delay profiles and comparing the created two delay profiles, delay propagation for each channel can be accurately detected.

[0030] The communication device according to the present invention is created by extracting a predetermined length from each of the cyclically shifted first reference codes from the reference points sequentially shifted in any direction as the two known reference codes. And a second code created by extracting the predetermined length from each of the first codes and a reference point in the circulating second reference code in which the reference point is sequentially shifted in a direction opposite to the above direction. And using any one of the above.

According to the present invention, in each of the created delay profiles, two known reference codes unique to each channel are used so that the delay profile adjacent to the delay profile of each channel is not the same channel. Therefore, the receiving apparatus that receives the signal in which the two known reference codes are multiplexed at the same time compares the paths in the two delay profiles created by the correlation value calculation processing, so that the delay propagation of each channel is large. Even in the case or when the signal of each channel includes a delayed wave, the delay propagation for each channel can be accurately detected.

The communication device according to the present invention has two different communication devices.
Receiving means for receiving a signal in which a transmission signal of each channel obtained by multiplexing two channel-specific known reference codes at the same time is multiplexed in the same frequency band; and a first circulating reference code and a second circulating reference code, respectively. By calculating a correlation value using the signal received by the receiving means,
It is characterized by comprising delay profile creation means for creating a first delay profile and a second delay profile, respectively, and detection means for detecting a delay for each channel using the two delay profiles.

According to the present invention, the first reference code and the second reference code
By creating two delay profiles for each channel using the reference code and comparing the created two delay profiles, it is possible to accurately detect delay propagation for each channel.

[0034] In the communication apparatus according to the present invention, the receiving means may extract a predetermined length from each point of the first reference code, the reference point being sequentially shifted in any direction, as the two known reference codes. The first created by doing
Any of the codes, and any of the second codes created by extracting the predetermined length from each of the second reference codes where the reference point is sequentially shifted in a direction opposite to the direction. , Is used to receive a transmission signal of each channel.

According to the present invention, a signal to be received is, for each of the delay profiles to be created, two channel-specific two created so that the delay profile adjacent to the delay profile of each channel is not the same channel.
Since two known reference codes are used, by comparing paths in two delay profiles created using the received signal, when delay propagation of each channel is large or when a signal of each channel includes a delayed wave, Also,
Delay propagation for each channel can be accurately detected.

[0036] In the communication apparatus according to the present invention, the detecting means may adjust the position of each of the delay profiles so that the reference phase at which the size of the path of the desired wave is maximized when there is no delay for the predetermined channel. Adjusting means for adjusting the position, the recognizing means for recognizing, as the path of the predetermined channel, a path that matches in each of the delay profiles whose positions have been adjusted, and a phase difference between the phase of the recognized path and the reference phase. And delay detecting means for detecting as a path delay.

According to the invention, two known reference codes for each channel are used in each delay profile created.
Since the delay profile adjacent to the delay profile of each channel is created so as not to be of the same channel, the path in which the I component and the Q component match in the two delay profiles, that is, the size and the phase match. The path can be recognized as a path of the same channel. Thereby, even when the delay propagation of each channel is large or the signal of each channel includes a delayed wave, the delay propagation of each channel can be detected more accurately.

[0038] A base station apparatus according to the present invention is characterized by comprising a transmission unit provided with any one of the above communication devices and a reception unit provided with any one of the above communication devices.

According to the present invention, by providing a communication device capable of accurately detecting the propagation delay of each channel, it is possible to provide a base station device that performs good communication.

A communication terminal device according to the present invention includes any one of the communication devices described above.

According to the present invention, by providing a communication device capable of accurately detecting the propagation delay of each channel, it is possible to provide a communication terminal device that performs good communication.

A communication terminal apparatus according to the present invention performs wireless communication with the base station apparatus.

According to the present invention, it is possible to provide a communication terminal device that performs good communication by performing wireless communication with a base station device provided with a communication device capable of accurately detecting a propagation delay for each channel. .

According to the known reference signal allocation method of the present invention, a plurality of first codes are extracted by extracting a predetermined length from each of the cyclically shifted first reference codes from the reference points sequentially shifted in any direction. A first code creating step of creating, and a plurality of second codes are created by extracting the predetermined length from each of the cyclically shifted second reference codes whose reference points are sequentially shifted in the same direction as the direction. A two-code creating step, and a candidate code setting step of setting any of the unselected ones of the plurality of first codes to a candidate first code and setting any of the unselected ones of the plurality of second codes to a candidate second code;
A channel in which a code extracted by a predetermined length from a point shifted by an arbitrary section from the leading end of the candidate first code has a first code included in the leading end selected as a known reference code, and a channel from the leading end of the candidate second code. The second code whose predetermined length is extracted from the point shifted from the arbitrary section is included in the leading end.
A determining step of determining whether or not a channel whose code is selected as a known reference code is different; and determining a candidate first code and a candidate second code when the respective channels are different by using a predetermined channel-specific known code. And a selecting step for selecting as a reference code.

According to the present invention, in each of the delay profiles created in the receiving apparatus, the delay profile adjacent to the delay profile of each channel is set to be unique to each channel created so as not to be a delay profile of the same channel. Since two known reference codes are assigned to each channel, in the receiving apparatus, the two
By generating two delay profiles for each channel by correlation value calculation processing using two known reference codes and comparing the two generated delay profiles, it is possible to accurately detect delay propagation for each channel. .

The communication method according to the present invention employs two different communication methods.
A receiving step of receiving a signal in which transmission signals of respective channels obtained by multiplexing two channel-specific known reference codes at the same time are multiplexed in the same frequency band; and a first circulating reference code and a second circulating reference code. By calculating a correlation value using the signal received by the receiving means,
A delay profile creation step of creating a first delay profile and a second delay profile, respectively, and the delay phases so as to match a reference phase that maximizes a path size of a desired wave when there is no delay for a predetermined channel. An adjusting step of adjusting the position of the profile; a recognizing step of recognizing, as a path of the predetermined channel, a path that matches in each of the delay profiles whose positions have been adjusted; and a phase of the phase of the recognized path and the reference phase. A delay detecting step of detecting a phase difference as a delay of this path.

According to the present invention, a signal in which two different known reference codes are multiplexed at the same time is received.
By generating two delay profiles for each channel by correlation value calculation processing using two known reference codes and comparing the two generated delay profiles, it is possible to accurately detect delay propagation for each channel. .

[0048]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The gist of the present invention is that a signal obtained by multiplexing two different channel-specific known reference codes at the same time is used as a known reference signal. Furthermore, the correlation value calculation process using the signal obtained by multiplexing the transmission signals of the respective channels obtained by multiplexing the known reference codes at the same time in the same frequency band and the first reference code and the second reference code results in two values. Create a delay profile,
By comparing the paths in these delay profiles, the delay of each channel is detected.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment) FIG. 1 is a block diagram showing a configuration of a transmitter in a CDMA communication apparatus according to an embodiment of the present invention. In FIG. 1, the diffusion unit 101
A spreading process is performed on transmission data using a spreading code assigned to a transmission channel of the transmitter. Time multiplexing unit 1
No. 02 creates a transmission signal by multiplexing a midamble pattern, that is, the first midamble pattern and the second midamble pattern, and the transmission data after the spreading process into a frame. As shown in FIG. 12, a frame format mainly including a data section 1, a midamble section and a data section 2 is used.
The details of the frame format and the midamble pattern will be described later.

Radio section 103 performs predetermined transmission processing such as frequency conversion on the transmission signal created by time multiplexing section 102, and transmits the processed transmission signal via antenna 104.

FIG. 2 shows a CD according to an embodiment of the present invention.
FIG. 2 is a block diagram illustrating a configuration of a receiver in the MA communication device. In FIG. 2, receiving section 202 performs predetermined receiving processing such as frequency conversion on a signal (received signal) received via an antenna, and separates the received signal after the above processing into separating section 2.
03 and the storage unit 207. This received signal is
Signals transmitted by a plurality of transmitters are signals multiplexed in the same frequency band. Each of the plurality of transmitters has the configuration shown in FIG. 1 and outputs a signal to the receiver shown in FIG. 2 using a different channel.

Storage section 207 stores the received signal after the above processing, and outputs the received signal to correlation sections 208 to 210 described later. The separating unit 203 separates a signal of 512 chips received from the reference time out of the received signals after the above processing. The correlation unit 204 performs a correlation value calculation process using the separated 512-chip received signal and the basic code 1 assigned to each channel, and then creates a delay profile using the calculated correlation value. I do.

The correlation section 205 performs a correlation value calculation process using the separated 512-chip reception signal and the basic code 2 assigned to each channel, and then delays using the calculated correlation value. Create a profile.

The comparing / channel estimating section 206 includes a correlating section 204
Then, channel estimation is performed for each channel using the delay profile created by each of correlation section 205. That is, comparison / channel estimation section 206 detects the path for each channel and the delay propagation of this path using the delay profile.

Correlation sections 208 to 210 receive section 202 using spread codes assigned to the respective channels based on the channel estimation result by comparison / channel estimation section 206.
Performs a despreading process on the received signal from. The synchronous detector 211 to the synchronous detector 213 are respectively
A synchronous detection process is performed on the signal after the despreading process by the correlator 210. The combining unit 214 combines the signals after the synchronous detection processing by the synchronous detection units 211 to 213 and outputs a demodulated signal.

In FIG. 2, as an example, in order to describe a case where three paths are handled for each channel, a configuration in which three systems of a correlation unit and a synchronous detection unit are provided is shown. Is applicable even when the number of systems of the correlation unit and the synchronous detection unit is appropriately changed.

Next, a method of creating a midamble pattern used for each channel will be described with reference to FIGS. Here, a case where a midamble pattern for eight channels is created will be described. In the present embodiment, a first midamble pattern (first code) and a second midamble pattern (second code)
2) are assigned to each channel. First, a procedure for creating the first midamble pattern will be described with reference to FIG.

FIG. 3 shows a CD according to an embodiment of the present invention.
FIG. 9 is a schematic diagram showing a procedure for creating a first midamble pattern used by the MA communication device. As shown in FIG. 3, the first midamble pattern used for each channel is created according to the following procedure using a first basic code (first reference code) circulating in a cycle of 456 chips. This first basic code is known to the receiver shown in FIG. 2 and differs from each other by W (= 5).
7) Blocks A to H having chip length codes are included.

First, as a first step, a reference position is determined in the basic code, and the determined reference position is sequentially shifted rightward in the figure by {W × (n-1)} chips for each channel. Here, W = 57 chips, and n is the number of channels. As the number of chips to be shifted,
Channel 1, channel 2, channel 3 and channel 8
In this case, the values are 0, W, 2W, and 7W, respectively.
Note that the direction in which the reference position is shifted may be the left direction in the figure.

As a second step, for each channel, a code having a predetermined length is extracted from the shifted reference position in the basic code. As a result, each extracted code has a total length of 456 chips. Here, as an example, the predetermined length is 456 chips.

As a third step, in each code of 456 chips in length as a whole, a leading block is added to the end to make a code of 512 chips in length, and this code is used as a first midamble pattern of each channel.
That is, for example, for the channel 1, the leading block A in the code having a total length of 456 chips
Is added as a block A ′ after the end, that is, after the block H, to create a first midamble pattern “ABCDEFGHA ′” of the channel 1.

Next, the procedure for creating the second midamble pattern will be described with reference to FIG. FIG. 4 is a schematic diagram showing a procedure for creating a second midamble pattern used by the CDMA communication device according to one embodiment of the present invention. As shown in FIG. 4, the second midamble pattern used for each channel is created according to the following procedure using a second basic code (second reference code) circulating in a cycle of 456 chips. This second basic code is known to the receiver shown in FIG. 2 and includes eight blocks J to Q having codes of different W (= 57) chip lengths.

First, as a first step, a reference position is determined in the basic code, and the determined reference position is sequentially shifted by {W × (n−1)} chips for each channel in the left direction (first midamble) in the figure. In the direction opposite to the direction of creation). Here, W = 57 chips, and n is the number of channels. The number of chips to be shifted is 0, W, 2W, and 7W in the case of channel 1, channel 2, channel 3, and channel 8, respectively. Note that if the direction of shifting the reference position is opposite to the direction of shifting the reference position when the first midamble pattern is created,
Either direction may be used.

As a second step, for each channel, a code having a predetermined length is extracted from the shifted reference position in the basic code. As a result, each extracted code has a total length of 456 chips. Note that the predetermined length is the same as the predetermined length when the first midamble pattern was created.

As a third step, in each code having a total length of 456 chips, a leading block is added to the end to form a code having a total length of 512 chips, and this code is used as a second midamble pattern of each channel. . That is, for example, for the channel 1, the leading block Q in the code having a total length of 456 chips is replaced by the terminal Q, that is, the block Q ′ after the block P.
, A second midamble pattern “QJKLMNOPQ ′” of channel 1 is created.

Next, the operation of the CDMA communication apparatus having the above configuration will be described. First, the operation of the transmitter in the CDMA communication apparatus having the above configuration will be described with reference to FIGS. FIG. 5 is a schematic diagram showing the transmission timing of the transmitter in the CDMA communication device according to one embodiment of the present invention.

Referring to FIG. 1, transmission data is subjected to spreading processing in spreading section 101 using a spreading code assigned to a transmission channel of the present transmitter. The transmission data after the spreading process is sent to time multiplexing section 102.

[0069] Of the midamble patterns created according to the above-described procedure, the first midamble pattern and the second midamble pattern assigned to the transmission channel of the present transmitter are sent to time multiplexing section 102.

[0070] Time multiplexing section 102 multiplexes the transmission data, the first midamble pattern, and the second midamble pattern after the spreading process into a frame to generate a transmission signal. That is, the transmission data after the spreading process is multiplexed on the data part (here, data part 1 and data part 2) in the frame shown in FIG. 5, and the first midamble pattern and the second midamble pattern are Midamble section (512
The transmission signal is created by being multiplexed in the chip section. Here, in the midamble part, the first midamble pattern and the second midamble pattern are multiplexed on the same time.

The transmission signal generated by time multiplexing section 102 is transmitted via antenna 104 after predetermined transmission processing such as frequency conversion is performed by radio section 103.

Next, the operation of the receiver in the CDMA communication apparatus having the above configuration will be described with reference to FIG. A signal received via the antenna 201 is subjected to predetermined reception processing such as frequency conversion by the reception unit 202. The received signal after the above processing is sent to separation section 203 and storage section 207. The storage unit 207 stores the received signal after the above processing.

The separation section 203 separates the 512-chip signal received from the reference time in the received signal after the above processing, and further, only 456 chips from the end of the separated 512-chip length signal. Cut off.
As described above, the reference time means that when there is no propagation delay, the front end of each midamble part in the signal transmitted by each transmitter (each mobile station) is received by the receiver (base station). Time.

In correlation section 204 and correlation section 205, a correlation value calculation process using the signal of 456 chip length sent from separation section 203 is performed. That is, the correlation unit 2
04 and the correlation unit 205 calculate a correlation value between the 456-chip length received signal and the first basic code and a correlation value between the 456-chip length received signal and the second basic code.

More specifically, the correlation unit 204 uses the first basic code shown in FIG.
The phase of the signal having a length of 56 chips is multiplied by the first basic code while being shifted one chip at a time, and a correlation value at each phase is calculated. Similarly, the correlation unit 205
In, the correlation value is calculated using the second basic code shown in FIG.

Further, correlation section 204 and correlation section 205
In, a delay profile is created using the respective correlation values calculated as described above. The details of the created delay profile will be described later.
The created delay profile is compared with the comparison / channel estimation unit 20.
6 is output.

In comparison / channel estimation section 206, channel estimation for each channel is performed using each delay profile created by correlation section 204 and correlation section 205. That is, a path for each channel and delay propagation of this path are detected using each of the delay profiles. The channel estimation result is output to correlation sections 208 to 210.

In correlation sections 208 to 210,
Despreading processing is performed on the received signal sent from storage section 207 based on the channel estimation result by comparison / channel estimation section 206. That is, the received signal transmitted from storage section 207 is received at correlation section 208 to correlation section 210 at a timing in consideration of the delay time of each of the three paths estimated by comparison / channel estimation section 206 for each channel. A despreading process is performed on the signal. In the present embodiment, the correlation units 208 to 2
The case where despreading is performed by using three correlators of ten is described as an example, but the number of correlators is not limited.

The synchronous detectors 211 to 213 perform synchronous detection on the signals despread by the correlators 208 to 210, respectively.
The demodulated signal is obtained by synthesizing the synchronously detected signals by the synthesizing unit 214.

Next, a description will be given of a channel estimation method by the comparison / channel estimation unit in the transmitter in the CDMA communication apparatus having the above configuration. Here, for the sake of simplicity, it is assumed that the sum of the propagation delay and the delay dispersion is equal to or less than the W chip length, and that there is no delay wave in the signal from each channel.

In comparison / channel estimation section 206, channel estimation is performed for each channel using the delay profiles created by correlation section 204 and correlation section 205, respectively. Here, first, a delay profile created by each of correlation section 204 and correlation section 205 will be described with reference to FIG.

FIG. 6A is a diagram showing an example of a delay profile created by the correlation section 204 in the receiver in the CDMA communication apparatus according to one embodiment of the present invention, and FIG. CDM according to one embodiment of the present invention
FIG. 9 is a diagram illustrating an example of a delay profile created by a correlation unit 205 in a receiver in the A communication device.

As shown in FIG. 6A, when the correlation value is calculated by the correlation unit 204,
When the code of the midamble part from any of the mobile stations included in the 56-chip length signal matches the above-mentioned known first basic code, the correlation value becomes maximum,
A path having a certain size appears.

Therefore, for example, in FIG. 6A, the path 601a, the path 602a, the path 603a, and the path 6
The point in time when each value of 08a is the maximum is determined by the number of the midamble part of each of the mobile station 1, mobile station 2, mobile station 3 and mobile station 8 included in the signal of 456 chip length. One midamble pattern corresponds to the time when the above-mentioned known first basic code matches.

Similarly, as shown in FIG. 6B, when the correlation value calculation process is
And the code of the midamble part from any mobile station included in the signal of 456 chip length from
When the basic code matches, the correlation value becomes maximum, and a path having a certain size appears.

Therefore, for example, in FIG. 6B, the path 601b, the path 602b, the path 603b, and the path 6
The point in time at which each value of 08b is the maximum is determined by the number of the midamble portion of each of the mobile stations 1, 2, 3, and 8 included in the 456-chip length signal. The 2 midamble pattern corresponds to a point in time when the pattern matches the known second basic code.

As described above, when the sum of the propagation delay and the delay dispersion of each mobile station is smaller than the W (= 57) chip length, a path having a certain size on the delay profile appears. The section is determined for each mobile station. That is, in the above case, the paths corresponding to the mobile stations 1 to 8 are respectively 1 to 8 W chip sections (delay profile width) in the delay profiles shown in FIGS. 6A and 6B. ).

Note that the position relationship between the W chip section of each mobile station in FIG. 6A and the W chip section of each mobile station in FIG. 6B is reversed. , The direction of shifting the reference position in the first step described above is reversed between the first midamble pattern and the second midamble pattern. Due to that.

Further, correlation section 204 and correlation section 205
Since the correlation value calculation process is performed using the first basic code and the second basic code which are respectively circulated in FIG. 6A and FIG.
The delay profile shown in (b) is cyclic.

That is, immediately before the one W chip section in FIG. 6A, eight W chip sections are located.
, W chip sections are located immediately before the W chip sections, and similarly, W chip sections of 6, 5, 4,... Also, immediately after the 8 W chip sections in FIG. 6A, 1, 2, 3,... W chip sections are located. vice versa,
In FIG. 6B, immediately before the 8 W chip section, one W chip section is located. Immediately before the 1 W chip section, 2 W chip sections are located. 4,
5 W chip sections are located. Also, immediately after one chip section in FIG. 6B, 8, 7, 6,... W chip sections are located.

In comparison / channel estimation section 206, channel estimation is performed using the two delay profiles described above. Here, a case where channel estimation of channel 1 (mobile station 1) is performed will be described as an example.

Referring to the transmission signal of channel 1 in FIG. 5, the first midamble pattern and the second midamble pattern in the midamble portion are multiplexed on the same time axis. Therefore, the I component and the Q component corresponding to the channel 1 path in the delay profile shown in FIG. 6A are respectively the I component and the Q component corresponding to the channel 1 path in the delay profile shown in FIG. It is almost the same as the component. That is, FIG.
The difference between the I component and the Q component between the channel 1 path in the delay profile shown in FIG. 6A and the channel 1 path in the delay profile shown in FIG. 6B is equal to or less than a predetermined error range.

As a result, the size of the path of channel 1 in the delay profile shown in FIG.
The path size of channel 1 in the delay profile shown in FIG. 6B is substantially the same, and the propagation delay of channel 1 detected from the delay profile shown in FIG. The propagation delay of the channel 1 detected from the delay profile shown in FIG.

That is, in each of the delay profiles shown in FIGS. 6A and 6B, the I component and the Q component corresponding to path 1 are substantially the same.
Is the same as the phase at which the value of the path 601b is the largest, and the size of the path 601a and the size of the path 601b are substantially the same. In other words, paths whose difference in each of the I component and the Q component exceeds a predetermined error range, that is, paths whose difference in each of the phase and magnitude of the path exceeds a predetermined error range are the same channel. It can be determined that it is not a pass.

Therefore, in comparison / channel estimation section 206, first, the two delay profiles are determined by using channel 1
In the W chip section as a reference. As a result, the delay profile based on the first basic code shown in FIG. 6A is circulated as shown in FIG. 7A. FIG.
The delay profile based on the second basic code shown in FIG. 7B is circulated as shown in FIG.

Next, the phase (reference phase) 701 at which the size of the path of the desired wave (main wave) is maximized so that the W chip sections of channel 1 match, that is, when channel 1 has no delay. As shown in FIG. 7A and FIG.
After adjusting the position of each delay profile after the tour shown in (b), each delay profile is compared. FIG. 8 shows each delay profile after the position adjustment.

More specifically, the respective delay profiles after the position adjustment shown in FIG. 8 are compared, and if there is a coincident path, that is, for example, an error in phase and magnitude is set to be equal to or less than a predetermined error range. In the case where there are two paths, the path is set as the channel 1 path. Thereby, the propagation delay of channel 1 is detected. Note that the predetermined error range is appropriately set according to various conditions.

When the sum of the propagation delay and the delay dispersion is larger than the length of the W chip, FIG.
In the delay profile shown in (b), for example, the path of channel 1 is not the W chip section of channel 1,
Appears in the W chip section of another channel. For this reason, it was difficult to detect the channel 1 path by the conventional method.

However, in the present embodiment, as described above, the first midamble pattern and the second midamble pattern of the midamble portion of the transmission signal are multiplexed on the same time axis, and In each delay profile created by the correlation value calculation process between the signal and the two basic codes, the I component and the Q component corresponding to each channel are substantially the same. That is, the path size and the phase difference of each channel are substantially the same.

Further, when the first midamble pattern and the second midamble pattern are created, the directions in which the reference positions are shifted in the first step are opposite to each other. As is clear from the respective delay profiles (for example, FIG. 6), the W chip section of a channel adjacent to the W chip section of a certain channel is reversed in each delay profile.

For example, paying attention to the W chip section of the channel 3, in the delay profile of FIG. 6A, the W chip section of the channel 4 is located on the right side in the figure, and the channel is located on the left side in the figure. Two W chip sections are located. Conversely, in the delay profile of FIG. 6B, the W chip section of channel 2 is located on the right side in the figure, and the W chip section of channel 4 is located on the left side in the figure.

Therefore, in each delay profile,
It can be said that the size and phase of the path of a certain channel and the size and phase of the path of another channel do not almost completely match. In other words, in each delay profile, each path having substantially the same magnitude and phase is likely to be a path of the same channel.

Therefore, even when the sum of the propagation delay and the delay dispersion is larger than the W chip length, the channel estimation of each channel can be performed by the method described above. For example, as shown in FIG. 9, when the delay propagation of the signal from channel 1 is larger than the W chip length, the path of channel 1 does not appear in the W chip section of channel 1 in the two delay profiles. Here, due to the above factors,
In each of the delay profiles, paths that substantially match, that is, paths whose differences in magnitude and phase are equal to or smaller than a predetermined error range, can be recognized as paths of the same channel. In FIG. 9, the path 90
1a and the path 901b have substantially the same size and phase, so that this path 901a (path 901b) is
Detected as a path.

The case where the receiver in the CDMA communication apparatus according to the present embodiment receives only a desired wave for each channel has been described above. It is also possible to receive waves. FIG. 10 shows an example of two delay profiles in this case.

As described above, since the first midamble pattern and the second midamble pattern of the midamble portion in the transmission signal are multiplexed on the same time axis, the correlation between this transmission signal and the two basic codes is determined. In each delay profile created by the value calculation process, the I component and the Q component corresponding to the path of the delay wave of each channel are substantially the same. That is, the magnitude and phase difference of the path value of the delay wave of each channel are also substantially the same.

Therefore, according to the above-described channel estimation method, not only a desired wave but also a path of a delayed wave can be detected for each channel. That is, in each delay profile whose position is adjusted so that the W chip sections of channel 1 shown in FIG.
001b, the path 1002a and the path 1002b, and the path 1003a and the path 1003b have substantially the same size and phase difference. Therefore, it is clear that these paths are paths corresponding to channel 1.

Specifically, from the size of the path, path 1001a (path 1001b) is the path of the desired wave of channel 1, and path 1002a (path 1002b) and path 1003a (path 1003b) are It is estimated to be a delayed wave. The path 1004b is estimated to be a delayed wave other than the channel 1 because a path having the same size and phase as the path 1004b does not exist on the delay profile based on the first basic code.

Thereafter, the propagation delays of the three detected paths are calculated by using the correlation units 208 to 210 shown in FIG.
Sent to Thereby, the correlation units 208 to 210
Can perform a despreading process on the received signal at a timing considering the respective propagation delays.

As described above, according to the present embodiment, the first midamble pattern and the second midamble pattern unique to each channel are created using the circulating first basic code and second basic code. . This first
The midamble pattern and the second midamble pattern are created such that the positional relationship of the W chip section is reversed in each delay profile created by the receiving device.

The transmitting apparatus transmits the above 2 in the midamble section.
A signal in which two midamble patterns are multiplexed on the same time axis is transmitted. Further, the receiver side generates a correlation value calculation process between the first basic code and the second basic code using a received signal. By comparing the size and phase of the path in each of the delay profiles, even when the propagation delay is greater than the W chip length or when there is a delay wave, channel estimation of each channel can be performed accurately. As a result, the propagation delay of each channel can be accurately detected without affecting the transmission capacity and the number of accommodated channels.

In the present embodiment, the case where the first midamble pattern and the second midamble pattern are created by the above-described method as an example has been described. However, the present invention is not limited to this. If the conditions are satisfied, the present invention can be applied to the case where the number of chips for shifting the reference position, the shifting direction, the total number of channels, and the like are appropriately changed in the first step.

That is, it is necessary to create each of the above midamble patterns so that the W chip section adjacent to the W chip section of each channel does not become the W chip section of the same channel in each of the two delay profiles. More specifically, the positional relationship (phase difference) between the W chip section of a certain channel and the W chip section of another channel is:
The two delay profiles need to be different from each other.

For this purpose, a channel to which the first midamble pattern having a code obtained by extracting a predetermined length from a point shifted by an arbitrary section from the front end of the first midamble pattern to be allocated to the predetermined channel at the front end is allocated. And a channel to which a second midamble pattern having a code obtained by extracting the predetermined length from a point shifted from the leading end of the second midamble pattern assigned to the predetermined channel by the arbitrary section at the leading end is assigned. As a difference, a first midamble pattern and a second midamble pattern to be assigned to each channel may be created.

For example, referring to FIGS. 3 and 4 described above, first, the W chip length is extracted from the point shifted W section from the leading end in the first midamble pattern assigned to channel 1, so that the block B of block B is extracted. The sign is obtained. The first midamble pattern having the block B at the leading end is channel 2. next,
By extracting the W chip length from the point shifted W section from the leading end in the second midamble pattern assigned to channel 1, the code of block J is obtained. The second midamble pattern having the block J at the leading end is a channel 8. Each midamble pattern may be created such that the channels are different for all the channels.

If each midamble pattern is assigned to each channel so as to satisfy the above conditions, the direction in which the reference position is shifted in the first step during the creation of the above-mentioned midamble pattern is changed by the first midamble pattern and the second midamble pattern. Even when the two midamble patterns are the same, each of the midamble patterns as shown in FIG. 5 can be assigned to channels 1 to 8 as a result.

Further, in the present embodiment, the case where the number of chips for shifting the reference position is set to W chips in all channels in the above-described first step when creating a midamble pattern has been described.
The present invention is not limited to this, and can be applied to a case where the number of chips for shifting the reference position for each channel is appropriately changed.
In this case, if the receiving device recognizes the number of chips that shift the reference position for each channel, the delay propagation for each channel can be accurately detected, as in the above-described example.

Furthermore, in the present embodiment, a case has been described in which the first midamble pattern and the second midamble pattern are used as the midamble pattern. However, the present invention is not limited to this, and the present invention is not limited to this. The present invention can be applied to a case where there are three or more patterns. In this case, it is possible to more accurately detect the propagation delay for each channel.

[0118]

As described above, according to the present invention,
The transmitting device multiplexes two midamble patterns unique to each channel created using the two kinds of cyclic codes on the same time axis in the midamble portion and transmits the multiplexed signals. Two delay profiles were created by calculating the correlation value between the signal and the two types of codes, and further, the sections where the paths of the detection target channels appeared when there was no propagation delay were circulated so as to match each other. To provide a communication device capable of accurately detecting the propagation delay of each mobile station without affecting the transmission capacity and the number of accommodated channels, since a path that substantially matches is detected in each of the delay profiles. Can be.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a transmitter in a CDMA communication apparatus according to one embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a receiver in the CDMA communication apparatus according to the embodiment.

FIG. 3 is a schematic diagram showing a procedure for creating a first midamble pattern used by the CDMA communication apparatus according to the embodiment.

FIG. 4 is a schematic diagram showing a procedure for creating a second midamble pattern used by the CDMA communication apparatus according to the embodiment.

FIG. 5 is a schematic diagram showing a transmission timing of a transmitter in the CDMA communication apparatus according to the embodiment.

FIG. 6A is a diagram illustrating an example of a delay profile created by the correlation unit 204 in the receiver in the CDMA communication apparatus according to the above embodiment. FIG. 6B is a diagram showing an example of the delay profile in the receiver in the CDMA communication apparatus according to the above embodiment. FIG. 4 is a diagram illustrating an example of a delay profile created by a correlation unit 205.

FIG. 7A is a diagram showing an example of a delay profile after a tour created by the correlator 204 in the receiver in the CDMA communication apparatus according to the embodiment. FIG. 7B is a diagram showing an example of the CDMA communication apparatus according to the embodiment. FIG. 9 is a diagram illustrating an example of a delay profile after a tour created by a correlation unit 205 in a receiver.

FIG. 8 is a diagram showing a state of comparison of a delay profile after position adjustment created by each correlator in the receiver in the CDMA communication apparatus according to the above embodiment.

FIG. 9 is a diagram showing a comparison of a position-adjusted delay profile (when a propagation delay is large) created by each correlator in the receiver in the CDMA communication apparatus according to the above embodiment.

FIG. 10 is a diagram showing a comparison of a position-adjusted delay profile (when a delay wave exists) created by each correlator in the receiver in the CDMA communication apparatus according to the above-described embodiment.

FIG. 11 is a schematic diagram showing a procedure for creating a midamble pattern in a conventional CDMA communication system.

FIG. 12 is a schematic diagram showing transmission timing of each mobile station in a conventional CDMA communication system.

FIG. 13 is a schematic diagram conceptually showing a situation in which a base station receives a transmission signal for each channel in a conventional CDMA communication system.

FIG. 14 is a diagram showing an example of a delay profile obtained by a correlation value calculation process in a base station in a conventional CDMA communication system.

[Explanation of symbols]

 Reference Signs List 101 spreading section 102 time multiplexing section 203 separation section 204, 205, 208, 209, 210 correlation section 206 comparison / channel estimation section

Claims (10)

[Claims] 1. A communication apparatus for transmitting a signal obtained by multiplexing two different reference codes unique to two channels at the same time. 2. The first known code generated by extracting a predetermined length from each of the cyclically shifted first reference codes at each of the reference points sequentially shifted in any direction, as the two known reference codes. The second to patrol with one of them
2. The method according to claim 1, wherein the reference code uses any one of the second codes created by extracting the predetermined length from each point where the reference point is sequentially shifted in a direction opposite to the direction. 2. The communication device according to 1. 3. A receiving means for receiving a signal in which transmission signals of respective channels obtained by multiplexing two different reference codes unique to two different channels at the same time in the same frequency band; A delay profile creation unit that creates a first delay profile and a second delay profile by calculating a correlation value using each of the circulating second reference codes and the signal received by the reception unit; Detecting means for detecting a delay for each channel using the two delay profiles;
A communication device comprising: 4. The receiving means is created by extracting a predetermined length from each point of the first reference code in which reference points are sequentially shifted in any direction as the two known reference codes. Any of the first symbols,
A channel using any one of the second codes created by extracting the predetermined length from each point in the second reference code in which the reference point is sequentially shifted in a direction opposite to the direction; 4. The communication device according to claim 3, wherein the communication device receives the transmission signal of (b). 5. An adjusting means for adjusting a position of each of the delay profiles so as to match a reference phase at which a size of a path of a desired wave becomes maximum when there is no delay for a predetermined channel. Recognizing means for recognizing, as a path of the predetermined channel, a path that matches in each of the delay profiles whose positions have been adjusted, and detecting a phase difference between a phase of the recognized path and the reference phase as a delay of the path. The communication device according to claim 3, further comprising: a delay detecting unit. 6. A transmission unit provided with the communication device according to claim 1 or 2, and a reception unit provided with the communication device according to any one of claims 3 to 5. A base station device characterized by the above-mentioned. 7. A communication terminal device comprising the communication device according to claim 1 or 2. 8. A communication terminal device for performing wireless communication with the base station device according to claim 6. 9. A first code creation step of creating a plurality of first codes by extracting a predetermined length from each point of a cyclically shifted first reference code in which reference points are sequentially shifted in any direction; A second code creating step of creating a plurality of second codes by extracting the predetermined length from each of the cyclically shifted second reference codes in which reference points are sequentially shifted in the same direction as the direction; A candidate code setting step in which any of the unselected first codes is a candidate first code, and any of the unselected ones of the plurality of second codes is a candidate second code; A channel whose first part includes a code extracted by a predetermined length from a point shifted by an arbitrary section as a known reference code, and a point shifted by the arbitrary section from the tip of the candidate second code. A determination step of determining whether or not the second code included in the leading end of the code extracted from the predetermined length is selected as a known reference code or not;
Selecting a candidate first code and a candidate second code as known reference codes specific to a predetermined channel when the respective channels are different from each other. 10. A receiving step of receiving a signal in which transmission signals of respective channels obtained by multiplexing mutually different known reference codes unique to two channels at the same time in a same frequency band; A delay profile creating step of creating a first delay profile and a second delay profile, respectively, by calculating a correlation value using each of the circulating second reference codes and the signal received by the receiving means; An adjusting step of adjusting the position of each of the delay profiles so as to match a reference phase at which the size of the path of the desired wave is maximized when there is no delay for the channel; A step of recognizing a path to be performed as a path of the predetermined channel; and a step of comparing a phase of the recognized path with the reference phase. A delay detecting step of detecting a phase difference as a delay of the path.