JP2003283461A - Communication apparatus in mobile communication system adopting code division multiple access system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication apparatus for code division multiple access communication for simplifying the configuration of a modulation- demodulation section so as to reduce the scale of hardware. <P>SOLUTION: A plurality of base band received signals are multiplexed in time division multiplexing so as to apply time division multiplex processing to path searching in one matched filter or demodulation processing in an inverse spread unit. Or time division multiplex processing is also applied to the outputs from a plurality of code generators in the case of path searching or demodulation to a plurality of codes. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication device in a code division multiple access (CDMA) type mobile communication system.

[0002]

2. Description of the Related Art Conventionally, code division multiple access (CDM) is used.
In the A) mobile communication system, a matched filter or a despreader is used for demodulating the spread spectrum received signal. The signal transmitted from the transmission side communication device is received by the reception side communication device via a plurality of routes. The signal on which the multipath signal is superimposed is input to the matched filter, and the output corresponding to the received signal strength of each multipath signal is output from the matched filter. Figure 2
0 shows a communication device using a conventional matched filter.
The received signal in the carrier frequency band received by the receiving antenna 2305 of the receiving side communication device 2300-2 is the wireless demodulation unit 23.
It is converted into a baseband spread spectrum signal according to 06 and further digitized by the A / D converter 2307. The digitized baseband spread spectrum signal is despread by the matched filter 2308. The matched filter 2308 is for path search,
The peak value is output at the timing synchronized with the multipath signal. The output of the matched filter 2308 is input to the peak detection unit 2309. The peak detection unit detects the timing at which a predetermined number of peak values with high reception intensity are output, and the despreading unit 2310-1 at each peak timing.
Set the phase of ~ n spreading codes. Each despreading unit despreads the spread spectrum signal at the timing designated by the peak detection unit 2309 and outputs the received signal at the symbol rate. The despreading unit 2310 multiplies the spread spectrum signal and the spreading code generated by the code generating unit 2350 by the multiplier 23.
Multiply by 51, adder 2352 and register 235
3 accumulates over one symbol period. The received signal of the symbol rate output from each despreading unit 2310 is R
After being input to the ake combiner 2311 and phase-corrected,
The Rake-combined received signal is output.

In the receiving side communication device shown in FIG. 20, antenna diversity is performed. The antenna diversity means antennas 2305-1 to 230-1 installed apart from each other by a predetermined distance.
The diversity effect is obtained by combining the signals respectively received by k. The received signal received by each antenna is processed by each wireless demodulation unit, A / D conversion unit, and baseband demodulation unit, and the antenna diversity combining unit 23 is processed.
At 38, diversity combining is performed.

In the configuration of FIG. 20, the path search is performed by the matched filter, and the despreading of the spread spectrum signal is performed by the despreader. In this case, the path search is not always performed, and is performed at regular intervals so as not to lose synchronization.
Correct the phase of 310.

[0005]

In the case of performing antenna diversity with a matched filter having a conventional configuration, it is necessary to configure the combination by path diversity and the combination by antenna diversity by separate circuits. Not limited to antenna diversity, when a diversity handover state is entered, and when QPSK is applied as a wireless modulation scheme, it is necessary to demodulate a plurality of received signals at the same time. In such a case, there is a problem that the circuit scale becomes huge.

Alternatively, in order to prevent the circuit scale from becoming enormous, there is also a configuration in which a circuit element such as a matched filter is time-divided to perform a path search. In such a conventional technique, a plurality of received signals or spread codes are sequentially switched at regular time intervals to execute a path search for a plurality of channels. However, the number of path searches (number of antennas,
When the number of channels, etc.) increases, the period in which the path search is executed and assigned to each signal becomes longer, and it is not possible to follow the time variation of the line. As described above, since the number of received signals or the number of spread codes that can be time-divided is limited, it is necessary to use a plurality of matched filters, which also leads to an increase in hardware scale.

Further, since the despreading unit for despreading the spread spectrum signal and demodulating the data must always operate, it is necessary to provide only the number of receiving channels, which leads to an increase in the hardware scale.

[0008]

According to the present invention, the hardware scale is reduced by operating the matched filter or the despreader in a time-division manner.

In order to realize the time-division processing of the matched filter, the present invention provides two methods.

(1) Time-division of reception baseband signal A plurality of reception baseband signals are time-division-multiplexed, and despreading processing of the reception signal time-division-multiplexed by an operation clock according to the number of time-division multiplexing is performed.

(2) Time-multiplexing of spread signal For a single received baseband signal, a plurality of spread codes are generated in the receiver, and code switching operation is performed by an operation clock according to the number of codes, whereby a plurality of signals Performs despreading processing.

The two methods are independent methods, and both or only one can be applied to the matched filter. By applying the multiplex processing at these times,
It is possible to increase the processing capability of the matched filter and reduce the hardware.

Further, the despreader can also reduce the number of parallel despreaders by performing time-division processing.

As described above, according to the present invention, both the matched filter and the despreader can be shared by a plurality of channels.
The matched filter can increase the number of sharable channels more than ever before. Further, the transmitting side also uses the time division multiplexing for a plurality of codes, so that the spreading unit can be shared and the hardware scale can be reduced.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a communication device in a code division multiple access communication system of the present invention will be described.

(Embodiment 1) As a first embodiment, FIG. 1 shows a communication apparatus (only a receiving section is shown) for performing antenna diversity. The number of antennas is not limited to two.

The received signals in the carrier frequency band received by the receiving antennas 101-1 and 101-2 are received by the radio demodulation unit 10.
2. The A / D converters 103-1 and 103-2 convert the digitalized baseband spread spectrum signal.
The first spread spectrum signal and the second spread spectrum signal originating from the receiving antennas 101-1 and 101-2 are input to the multiplexer 104 and become one spread spectrum signal that is time-multiplexed and combined. This is shown in FIG. 2 (b).

The multiplexer 104 includes a local oscillator 1
A clock having a frequency twice as high as the chip rate oscillated from 11 (n frequency if the number of antennas is n) is input. The local oscillator 111 receives a correction signal from the motion detection unit 110 and corrects the oscillation frequency. The motion detection unit 110 generates a correction signal at the cycle of the peak value output (received signal received on the same path) output from the matched filter 105 at the symbol rate. When the communication device of this embodiment is applied to a base station, the motion detecting unit 110 can be omitted by using a high-precision local oscillator.

The structure of the multiplexer 104 is shown in FIG.
Shown in. Clock 21 oscillated from local oscillator 111
The frequency 0 is divided by the frequency divider 211 to generate a clock 211 having a 1/2 cycle. The clock 211 is the first AN
The second A via the D gate 202 and the inverter 203
It is input to the ND gate 204. The first AND gate 202 receives the first spread spectrum signal 212 from the receiving antenna 101-1 and the second AND gate 203.
The second spread spectrum signal 213 derived from the receiving antenna 101-2 is input to the. The outputs of the first and second AND gates are output as the multiplexer output 214 via the OR gate 205. Therefore, the clock 21
When 1 is High, the AND gate 202 is opened and the first spread spectrum signal 212 is output. When the clock 211 is Low, the AND gate 204 is opened and the second spread spectrum signal 213 is output. Even when the number of antennas is n, a multiplexer can be configured by providing n AND gates and sequentially selecting them. With such a multiplexer, a spread spectrum signal 214 (two spread signals are multiplexed in one chip section) in which the spread spectrum signals from the respective antennas are time-multiplexed at the chip rate can be obtained.

In place of the configuration of multiplexing after A / D conversion, an analog multiplexer is used to time-multiplex the analog first spread spectrum signal and the second spread spectrum signal before A / D conversion. May be. However, when the number of multiplexed signals or the chip rate is high, it is more resistant to noise when digitized and then time-multiplexed.

The output of the multiplexer 104 is input to the matched filter 105. The structure of the matched filter 105 is shown in FIG. The time-multiplexed spread spectrum signal (multiplex signal) is output from the signal input terminal 301.
The spread code generated by the spread code generator 116 is input to the matched filter from the code input terminal. The time-multiplexed spread spectrum signal is received by the shift register 303-
1 to m2 are sequentially shifted. The spread code is held in the code holding registers 305-1 to 30-m after sequentially shifting the code shift registers 304-1 to 30-m. In the matched filter 105, the reception shift register 303 is
It has a delay element of time multiplex number 2 for one tap. If the time multiplex number is n, the reception shift register has n delay elements for one tap.

Reception shift registers 304-1 and 304-
The value of k2 (k = 2 * i (1 ≦ i ≦ m / 2)) and the values of the code holding registers 305-1 to 303-m are respectively multiplied by a multiplier 306.
−1 to m are multiplied, and the multiplication results are accumulated by the adders 307-2 to 307 to perform correlation calculation.

Thus, the reception shift register 303-
1, 21 to m2 are multipliers 306- for every other delay element.
1 to m are connected. Thereby, when the multiplex signal 214 is input, the correlation value corresponding to the first spread spectrum signal (antenna 1) and the correlation value corresponding to the second spread spectrum signal (antenna 2) are output terminal 3
It is output from 08. An example thereof is shown in FIG. The arrow shown by the solid line is the correlation value output for the signal from the antenna 1, and the arrow shown by the dotted line is the correlation value output for the signal from the antenna 2. In this way, the correlation value for the signal from the antenna 1 and the correlation value for the signal from the antenna 2 are alternately output (if there are n antennas,
The correlation values for the signals from n are sequentially output). This output is input to the peak detection unit 106, and a predetermined number (≦ number of despreading units) is selected in descending order of correlation value. Figure 4
In the example, timing 4 indicated by the six downward arrows
01 to 406 are selected. In this case, timings 401 to 404 based on the signal from the antenna 1 and timings 405 and 406 based on the signal from the antenna 2 are selected.

Timings 401 to 406 are transmitted to despreaders 107-1 to 10-n, respectively. The code generator 112 outputs the spread code with a phase that matches the transmitted timing. The despreading process is performed by multiplying the spread code and the received signal by the multiplier 113 and cumulatively adding over one symbol period by the adder 114 and the register 115. The despreading unit 107 operates with a clock having a cycle of 1/2 of the chip rate (1 / n when there are n antennas), so that the received signal is despread correctly.

The output from the despreading units 107-1 to 10-n is R
The signal is sent to the ake synthesizing unit 108, subjected to phase correction, and then synthesized, and output from the output terminal 109 as a demodulated output.

As another configuration, it is possible to perform both path search and despreading with a matched filter. At this time, the output of the matched filter is directly input to the Rake combiner. In this configuration, demodulation is always performed, and the matched filter needs to be constantly operated.

In the first embodiment, signals from a plurality of antennas are time-multiplexed so that signals from a plurality of antennas are processed by one matched filter 105. Also, the despreading units 107-1 to 10-n do not fix the signal to be despread by the antenna according to the timing given from the peak detection unit 106. Therefore, the peak detector 1
Each despreading unit 107 is designated by timing designation by 06.
The antenna diversity circuit can be omitted because the antenna can be selected together with the selection of the multipath signal that despreads. In this way, since the despreading unit is assigned to the signal of either antenna, it is possible to simplify the circuit configuration without providing the conventional antenna diversity circuit and still obtain the antenna diversity effect.

Since a signal having a strong reception strength can be selected from the multipath signals obtained from all the reception antennas, it is possible to obtain better reception sensitivity than the conventional antenna diversity. In the example of FIG. 4, in the case of the conventional configuration, the timings 401 to 40 for the antenna 1
3, the timings 405 to 407 are selected for the antenna 2. The multipath signal corresponding to timing 404, which has a higher reception intensity than the multipath signal corresponding to timing 407, is not used for demodulation. Further, when either of the antennas is in a position where the radio wave is insensitive, the demodulation output cannot be obtained from the despreading unit connected to the insensitive antenna in the conventional configuration. In the configuration, all the despreading units can be assigned to the antenna having the receiving sensitivity and all the despreading units can be operated. Therefore, it is possible to reduce waste of the circuit and obtain high performance.

Further, conventionally, in order to reduce the hardware scale, the path search is performed by switching the antenna output input to the matched filter in time division. However, in order to perform the path search with the required accuracy, it is necessary to operate the matched filter for a certain period. In this case, if the number of antennas is large (Example 2 described later, etc.), the time until the next path search for one antenna becomes long, so that the number of antennas that can be switched is limited. On the other hand, in the present embodiment, since the outputs of the respective antennas are time-multiplexed, it is possible to perform a path search for the outputs of a plurality of antennas within a certain period, which is more restrictive than the case where the matched filter is operated by time division. Few.

(Second Embodiment) Multi-sector means that a base station divides its service range (cell) into a plurality of sectors. The base station has a directional antenna corresponding to each sector, thereby communicating with mobile stations in the sector. FIG. 9 shows an example of multi-sector. FIG. 9 shows a three-sector configuration of sectors 902 to 904. For example, the signal transmitted from the mobile station 905 located in the center of the sector 904 is received by the base station 901 via the directional antenna corresponding to the sector 904 of the base station 901. On the other hand, the signal transmitted from the mobile station 906 located on the boundary between the sector 902 and the sector 904 is received by the base station 901 via the directional antennas corresponding to the sector 902 and the sector 904 of the base station 901. . This is called diversity handover.

FIG. 5 shows an embodiment in which the present invention is applied to a base station composed of multi-sectors shown in FIG. Two antenna diversity is used for each sector, and one base station has a total of six receiving antennas. The number of sectors and the number of antennas are not limited to the above examples. The function of each functional block in FIG. 5 is the same as the corresponding functional block in FIG. 1, and detailed description thereof will be omitted. The signal received by the receiving antenna of each sector is input to the multiplexer 504 and time-multiplexed. The output of the multiplexer 504 is s baseband demodulation units 530, which is the maximum number of mobile stations to which the base station can be connected.
-1 to s are input. Each baseband demodulation unit 530
Demodulates the signal transmitted from the mobile station using the spreading code assigned to each mobile station.

An example of the multiplexer is shown in FIG.
An example of the time-multiplexed received signal is shown in (b). The time-multiplexed reception signal is input to the matched filter 505 of each baseband demodulation unit 530, and the peak of the correlation value is detected by the peak detection unit 506. The multiplexer 504 is
It can be configured similarly to that shown in FIG.

FIG. 7 shows a structural example of the matched filter 505. The matched filter 505 includes received signal shift registers 703-1 to m6 and code shift register 704-1.
-M, code holding registers 705-1 to 70-m, multiplier 70
6 and adder 707, and their operations are similar to those of the corresponding configuration of FIG. However, the matched filter 50
Since 5 corresponds to 6 antennas, the reception shift register 7
An output tap to the multiplier is provided every six delay elements 03, so that the sum of products operation is performed on the received signals from the same antenna. An output example of the matched filter 505 is shown in FIG. Correlation values corresponding to the received signals from the antennas 1 to 6 are sequentially output, and the peak detection unit 506
Specifies the reception timing of a predetermined number of multipath signals from the one with the largest peak value to each despreading unit 507. When a signal is received from a mobile station (mobile station 906 in FIG. 9) on the sector boundary, as shown in FIG.
Timings 801 to 805 corresponding to signals received by
Besides, the timing 806 corresponding to the signal received by the antenna 501-1 forming another sector is selected.

On the other hand, when the mobile station 905 is located in the center of the sector like the mobile station 905, only the signals received by the directional antennas (for example, antennas 501-1 and 501-1) corresponding to one sector are demodulated. Will contribute to.

As described above, in this embodiment, the signals of all the antennas of all the sectors can be demodulated by the matched filter and despreader of one system. It is possible to find a strong path from the sector and combine it. Further, since the baseband demodulation unit is conventionally provided corresponding to each sector, the signal from the mobile station on the sector boundary is received by the baseband demodulation unit of each of the two sectors. On the other hand, in the configuration of the present embodiment, since the signals from the two sectors can be processed by one baseband demodulation unit, the connection capacity of the base station can be increased.

Further, since the received signal can be extracted from any sector, sector combination and inter-sector handover can be easily realized.

It should be noted that the present invention is not limited to the case where the received signals from all the sectors are time-multiplexed. Depending on the number of sectors and the chip rate, the above effects can be obtained even if they are grouped for every several adjacent sectors.

(Embodiment 3) In Embodiment 1 or 2, two series of received signals are time-multiplexed and demodulated. On the other hand, the third embodiment shows an embodiment in which two spread codes are time-multiplexed with respect to a received signal to perform demodulation processing. The demodulation of the received signal with a plurality of spreading codes in this way may be as follows because each mobile station communicates using the same frequency band in the CDMA mobile communication system.

(1) When the base station performs a path search for received signals from a plurality of channels (when communicating with a plurality of mobile stations to which different spreading codes are assigned, one mobile station is assigned a plurality of spreading codes). (2) When the mobile station performs a path search for received signals from multiple channels (including multiple channels with the same base station, multiple channels with multiple sectors, and multiple channels with multiple base stations) ( 3) As a wireless modulation method, QPSK (Quadrature Phase Sh
In the case of using ift keying), the base station or the mobile station performs a path search for a received signal spread by a spread signal different in in-phase component (I signal) and quadrature component (Q signal). 1 shows an embodiment of an applied communication device.
The function of each functional block in FIG. 10 is the same as the corresponding functional block in FIG. 1, and detailed description thereof will be omitted. In the present embodiment, the matched filter 1005 is input with the first spread code generated by the first code generation unit 1004-1 and the second spread code generated by the second code generation unit 1004-2. ing. Two Rake combining sections 1008-1, 1002 are provided according to the two spread codes, and the first R
The de-spreading unit 1007-1 to the ake combining unit 1008-1.
As for the output of k, the outputs of the despreading units 1007- (k + 1) to n are input to the second Rake combining unit 1008-2.

FIG. 11 shows a structural example of the matched filter 1005. The matched filter 1005 includes received signal shift registers 1104-1 to 110-4m, first code shift registers 1105-1 to m corresponding to the first spread code, and second code shift register 1106 corresponding to the second spread code.
-1 to m, the first code holding registers 1107-1 to m corresponding to the first spreading code, the second code holding registers 1108-1 to 1108 to m corresponding to the second spreading code, and the multiplier 111.
0, adder 1111 and their operation is similar to the corresponding configuration of FIG. However, matched filter 1
Since 005 despreads with two spreading codes, the selector 1109 is obtained. Each selector 1109-i has a first and a second code holding register (1107-i, 1108).
Alternately select i).

The correlation calculation of the matched filter 1005 is
When one sample of the received signal is input, the correlation calculation with the first spreading code is performed, the selector 1109 is switched, and the correlation calculation with the second spreading code is performed. Further selector 1109
And wait for the next sample. An output example is shown in FIG. The matched filter 1005 alternately outputs the correlation value with the first spreading code and the correlation value with the second spreading code. The output is sent to the peak detector 1006, and the peak timing is detected. A predetermined number of peak timings are selected from the larger one for each of the first and second spreading codes (peak timing 1 for the first spreading code).
201 to 1203, and peak timings 1204-1206 for the second spreading code).

The timing for the first spreading code is assigned to the despreading units 1007-1 to k, and the timing for the second spreading code is assigned to the despreading units 1007- (k + 1) to n. For example, which spreading code is used for the peak timing can be determined by referring to the switching timing of the selector 1109 of the matched filter. The despreading unit 1007 performs despreading processing in a phase according to the given peak timing. The output of the despreading unit corresponding to the first spreading code is input to the first Rake combining unit 1008-1, and the output of the despreading unit corresponding to the second spreading code is the second Rake combining unit 1008-2. Entered in. The Rake combining unit 1007 performs phase correction, Rake combining, and outputs the result as a demodulation output.

As described above, since the received signals of a plurality of channels can be demodulated by one matched filter, the circuit scale can be reduced. Further, even when the number of spreading codes is 2 or more, time multiplexing processing can be similarly performed by using a matched filter having a selector 1109 corresponding to the number of codes.

Furthermore, by combining the first or second embodiment with this embodiment, it is possible to carry out a path search with a plurality of codes for a plurality of baseband received signals. In this case, a multiplexer that time-multiplexes the digitized spread spectrum signals received by the plurality of antennas may be provided after the A / D converter 1003 (see FIG. 1 described later).
6 will be the same configuration). With this configuration, when a path search is performed on a plurality of received signals with a plurality of spreading codes (when a terminal having a plurality of antennas searches for signals from a plurality of base stations, a plurality of terminals on a sector boundary are used as base stations). This is effective when the station conducts a path search).

(Fourth Embodiment) FIG. 13 shows a fourth embodiment.
The structure of an anti-correlation unit that demodulates a plurality of channels by time multiplexing is shown. The fourth embodiment can be applied to the communication devices of the first to third embodiments described above. For example, in the case of the communication device of FIG. 1, the despreading unit 107 is used.
The despreading unit of the present embodiment can be applied instead of -1 to n. In this embodiment, a demodulation process of a received signal on which signals spread by a plurality of spreading codes are superimposed is performed by time multiplexing. FIG. 14 shows the operation timing of the despreading unit of this embodiment.

Received signal (multiplexer 1 in the example of FIG. 1)
04 output signal, A / D converter 1003 in the example of FIG.
Output signal) is input from the input terminal 1301 to the despreading unit. The code generators 1302-1 to 1302-1-n receive the timing designations detected by the peak detector and generate spreading codes corresponding to the respective channels at designated phases. Spreading codes 1401 to 1403 generated from each code generator 1302
Are time-multiplexed by the multiplexer 1303 (multiplexer output 1404). Spread code 14 time-multiplexed
04 is multiplied by the received signal 1405 by the multiplier 1304 and accumulated by the adder 1305 to obtain the despread result. Since the accumulation result 1406 is time-multiplexed, the demultiplexer 1306 decomposes the accumulation result into each channel and holds it in the registers 1307-1 to 1307-1.
The multiplexer 1308 has registers 1307-1 to n.
Are sequentially selected to accumulate the adder output for each channel. When the accumulation process is performed on the 1-symbol section, the despread result is output from the output terminal 1309.
It is output to the Rake combiner. The Rake combining unit separates the time-multiplexed despreading results and performs Rake combining corresponding to each spreading code.

In this way, the code generator 1302-1 receives one received signal from the input terminal 1301.
The n-ary operation with the spreading code generated in ~ n is time-multiplexed. The registers 1307-1 to 1307-1 are cleared in the initial state. Since the received signal is despread with a plurality of spreading codes, the demultiplexer 1306 and the multiplexer 1308 always register the register 1307 when the multiplexer 1303 selects the output of the code generator 1302-i and performs multiplication and accumulation, for example. Operate to select i. That is, the accumulation result is held in the register for each spreading code. After the calculation (multiplication / accumulation) for one chip of the spread codes 1 to n is completed, the calculation for the next one chip is repeated for each spread code 1 to n. After the calculation is completed for one symbol period, the value held in the registers 1307-1 to 1307-1 is set to the multiplexer 1
It is sequentially output to the output terminal 1309 through 308. After output, the contents of registers 1307-1-n are cleared,
The operation for the next symbol is similarly performed.

In this way, the demodulation operation of a plurality of channels is carried out by time multiplexing, and the hardware required for demodulation is reduced.

(Embodiment 5) Embodiment 5 is a modification of Embodiment 4. Code generator 1302-1 of the despreader of the fourth embodiment
.., n, a demultiplexer 1505, state registers 1502-1 to 150n, and a multiplexer 1503. The timing designation detected by the peak detection unit is performed on the status registers 1502-1 to 150-n, and the code generator 1504 generates a spreading code corresponding to each channel at a designated phase. The function of each functional block in FIG. 15 is the same as the corresponding functional block in FIG. 13, and detailed description thereof will be omitted.

Similar to the fourth embodiment, in addition to performing the time-division multiplexing operation with the spread code corresponding to each channel for one received signal input from the input terminal 1401, one Status register 1 for code generator 1404
By switching between 402-1 to 402-n, time-multiplexing operation is performed and the spread code of each channel is generated.

A general configuration of the code generator 1504 is shown in FIG.
5 shows.

(Embodiment 6) QPSK as a wireless modulation system
When (Quadrature Phase Shift Keying) is used, the baseband spread spectrum signal is divided into an in-phase component signal (I signal) and a quadrature component signal (Q signal). The hardware scale can be reduced by multiplexing and demodulating these two baseband signals. The structure is shown in FIG. The function of each functional block in FIG. 16 is the same as the corresponding functional block in FIG. 1, and detailed description thereof will be omitted.

In QPSK, the I signal and the Q signal are transmitted by carrier waves whose phases are deviated from each other by 90 °. Therefore, in the communication device on the receiving side, the oscillator 2505 and the oscillator 2
The I signal and the Q signal are demodulated into baseband spread spectrum signals by a phase shifter 2506 that shifts the carrier frequency oscillated from 505 by 90 °. However, the spread spectrum signals output from the low pass filters 2584 and 2585 have phase errors due to phase rotation on the propagation path, frequency error of the oscillator, and the like. On the other hand, four product-sum operations of I signal × I code, I signal × Q code, Q signal × I code, and Q signal × Q code ((II) and (I
Q), (QI), and (QQ) are displayed)
It is known that phase-corrected I and Q signals can be extracted.

The I and Q signals output from the low-pass filters 2584 and 2585 undergo A / D conversion and are input to the multiplexer 2509. I signal,
The Q signal is time-multiplexed by the multiplexer 2509. The situation is shown in FIG. The I signal 1701 and the Q signal 1702 input at the chip rate are output as a time-multiplexed spread spectrum signal 1703.

The structure of the matched filter 2581 is shown in FIG.
The configuration is the same as that of the matched filter shown in FIG. From the matched filter, four product-sum operation results 1705-11 to 14 are output at the chip rate. The output from the matched filter 2581 is input to the peak detection unit 2539. The peak detection unit 2539 calculates received power from the correlation value at each reception timing. The received power is ((II) +
It is obtained by (QQ)) 2 + ((IQ)-(QI)) 2. The received power is obtained at the chip rate, the peak of the received power is selected, and the timing is sent to each despreading unit 2582.

The operation of the despreading unit 2582 will be described. The peak timing is received from the peak detection unit 2539, and the I code generator 2540 and the Q code are synchronized with the timing.
The code generator 2541 uses a spreading code 170 used for despreading.
6, 1707 is generated. The I code and the Q code are time-multiplexed by the multiplexer 2542 and multiplied by the baseband received signal which is time-multiplexed by the multiplier 2543. As a result, four types of multiplication are executed in a time-multiplexed manner.

When the I signal is output from the multiplexer 2509, the multiplexer 2542 first selects the I code. The multiplier 2543 executes the operation (II), and the result is held in the register 2546. Multiplexer 25
45, the demultiplexer 2550 selects the register 2546 only when the operation (II) is performed. Next, the multiplexer 2542 first selects the Q code. Multiplier 2
The 543 executes the (IQ) operation, and the result is stored in the register 25.
Held at 47. The multiplexer 2545 and the demultiplexer 2550 select the register 2547 only when the (IQ) operation is performed. Then multiplexer 2
The Q signal is output from 509, and by the same processing, four types of product-sum operations are performed, and the registers 2547 to 254 are respectively operated.
Accumulated to 9. When accumulated over one symbol period, the four accumulated results held in the registers 2546 to 2549 are sent to the Rake combining unit 2551.

As described above, in the present embodiment, the four-phase phase-modulated spread spectrum signal is matched filter 2581.
And the despreader 2582 reduces the hardware scale by performing four types of sum-of-products calculation by time multiplexing.

In particular, when the I signal and the Q signal are received at different time points, the two signals are out of phase with each other, and therefore the correlation calculation for the I signal and the Q signal by the matched filter cannot be performed in a time division manner. Therefore, the signal of this embodiment,
The method of reducing hardware by time-multiplexing codes is particularly effective.

(Embodiment 7) In Embodiments 1 to 5, time division signal processing is applied to the receiving section. On the other hand, in the sixth embodiment, time division signal processing is applied to the transmitter. FIG. 18 shows a configuration example of the communication device (only the transmission unit is shown). The operation timing of this embodiment is shown in FIG.

Transmission data is input to the spreading section 1909 from the input terminals 1901-1 to 1901-1. Multiplexer 19
03 and the multiplexer 1904 operate in synchronization with each other, and when the multiplexer 1903 selects the input terminal 1901-i, the multiplexer 1904 generates a spread code that spreads the transmission data input from the terminal 1901-i. Select 1902-i. The multiplier 1905 multiplies the transmission data by the spreading code, and the transmission data is spread spectrum. The spectrum-spread transmission signal is input to the output combining unit 1910.

The signals to be multiplexed are cumulatively added by the adder 1906 and the register 1907. Register 190
7 is reset to zero in the initial state. The register 1908 latches the multiplexed signal during the cumulative addition so as not to be output to the D / A converter 1913. The multiplexed data D0 to Dn2004 are multiplied by the corresponding spreading codes C00 to Cn02008 during one chip period and output as output signals E00 to En02009. When the cumulative addition of the output signals E00 to En0 is completed,
The accumulated result held in the register 1907 is sent to the register 1908 and the register 1907 is reset to zero. The cumulative result held in the register 1908 is transferred via the D / A converter 1913 to the wireless modulation unit 1
The signal is input to 911, converted into a wireless signal, and output from the transmitting antenna 1912. After the time-division processing is executed for one symbol period at the chip rate, the input terminals 1901-1 to 1901-1
The next data is input from n.

As described above, in the present embodiment, a plurality of transmission data are spread with different codes and the time-multiplexed spread signal is output. Although FIG. 18 shows an example in which signals of a plurality of channels are multiplexed, the present invention can also be applied to a case of multiplexing I and Q signals by QPSK. The same calculation can be performed even when the input timing of the transmission data to each input terminal is different or the data rate of each transmission data is different.

In the present embodiment, since a plurality of spreading operations are time-multiplexed using one multiplier and one adder, the hardware scale of the spreading unit can be reduced.

A plurality of spread code generators 1902-1
~ N and multiplexer 1904 instead of the configuration,
Demultiplexer 150 shown in FIG. 15 (Example 5)
5, status registers 1502-1 to 150-n, multiplexer 1
It is also possible to use the same configuration as the code generator 503 and the code generator 1504.

[0066]

According to the present invention, a plurality of baseband received signals such as antenna diversity, sector diversity, I (in-phase) signal and Q (quadrature) signal are processed by the same demodulator by time-division multiplexing. Thereby, it is possible to suppress an increase in hardware scale with respect to an increase in the number of input baseband received signals.

Further, a single demodulator performs time-division demodulation processing on signals spread with different codes, such as received signals from a plurality of mobile stations, to suppress increase in hardware and to cope with large capacity. be able to.

[Brief description of drawings]

FIG. 1 is a configuration of a receiving unit of a communication device according to a first embodiment.

FIG. 2 is a diagram showing a configuration of a multiplexer and an input / output timing thereof according to the first embodiment.

FIG. 3 is a configuration of a matched filter according to the first embodiment.

FIG. 4 is a diagram showing an output and a detected peak of the matched filter of the first embodiment.

FIG. 5 is a configuration of a receiving unit of the communication device according to the second embodiment.

FIG. 6 is a diagram showing the configuration of a multiplexer and its input / output timing according to a second embodiment.

FIG. 7 is a configuration of a matched filter according to the second embodiment.

FIG. 8 is a diagram showing an output and a detected peak of the matched filter according to the second embodiment.

FIG. 9 is a diagram showing a multi-sector state.

FIG. 10 is a configuration of a receiving unit of the communication device according to the third embodiment.

FIG. 11 is a configuration of a matched filter according to the third embodiment.

FIG. 12 is a peak detected as an output of the matched filter of the third embodiment.

FIG. 13 is a configuration of a despreading unit of the code division multiple access demodulator of the fourth embodiment.

FIG. 14 is an operation of the despreading unit of the code division multiple access demodulation device of the fourth embodiment.

FIG. 15 is a configuration of a despreading unit of the code division multiple access demodulation device of the fifth embodiment.

FIG. 16 shows the structure of the demodulation device of the sixth embodiment.

FIG. 17 is a diagram showing input / output timing of the sixth embodiment.

FIG. 18 is a configuration of a transmission unit of the communication device according to the seventh embodiment.

FIG. 19 is a diagram showing input / output timing of the seventh embodiment.

FIG. 20 is a configuration of a code division multiple access communication device according to the prior art.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shin Doi             1-280, Higashi Koikekubo, Kokubunji, Tokyo             Central Research Laboratory, Hitachi, Ltd. F term (reference) 5K022 EE02 EE14 EE22 EE33

Claims (21)

[Claims] In a communication device in a code division multiple access mobile communication system, radio demodulation for demodulating received signals of a plurality of carrier frequency bands received by a plurality of receiving antennas into spread spectrum signals of a plurality of basebands. A unit, a multiplexer that time-multiplexes the plurality of baseband spread spectrum signals, a matched filter that performs a correlation operation between the time-multiplexed baseband spread spectrum signals and spread codes, and outputs a correlation value, Among the peak values of the correlation value, a peak detection unit that detects a predetermined number of peak values in descending order of received power, and a spreading code that matches the phase with the timing detected by the peak detection unit A despreading unit that despreads a spread spectrum signal. 2. The communication apparatus according to claim 1, wherein the multiplexer divides a chip section into n (n = number of time-multiplexed) sub-sections as the time-multiplexed baseband spread spectrum signal. A baseband spread spectrum signal originating from each of the receiving antennas is output to each of the partial sections. 3. The communication device according to claim 1, wherein the matched filter has a first shift register for shifting the spread code and a second shift for shifting the time-multiplexed baseband spread spectrum signal. A register is provided, and while the first shift register shifts the spread code by one register, the second shift register shifts the time-multiplexed baseband spectrum signal to n (n = n).
A communication device characterized by shifting the number of time-multiplexed registers. 4. The communication device according to claim 1, wherein the plurality of receiving antennas include receiving antennas forming a plurality of sectors. 5. In a communication device in a code division multiple access mobile communication system, a radio demodulation unit for demodulating a reception signal of a carrier frequency band received by a reception antenna into a baseband spread spectrum signal, and the baseband spectrum. A matched filter that performs a correlation operation between a spread signal and a spread code in which multiple spread codes are time-multiplexed, and outputs a correlation value, and among the peak values of the above correlation values, the one with a large received power for each of the multiple spread codes. A peak detector that detects a predetermined number of peak values in order, and a despreader that despreads the baseband spread spectrum signal with a spreading code whose phase matches the timing detected by the peak detector. A communication device characterized by the above. 6. The communication device according to claim 5, wherein the matched filter includes a plurality of first shift registers for shifting the spread codes, and spread codes stored in the plurality of first shift registers. And a second shift register for shifting the baseband spread spectrum signal, and while the second shift register shifts the baseband spread spectrum signal by one register, A communication device, wherein the selector switches and outputs each spreading code stored in the plurality of first shift registers. 7. The communication device according to claim 5, wherein the plurality of spreading codes are spreading codes assigned to a plurality of terminals. 8. The communication device according to claim 5, wherein the plurality of spreading codes are spreading codes assigned to different base stations or different sectors. 9. The communication device according to claim 5, wherein the plurality of spreading codes are spreading codes assigned to different base stations or different sectors. 10. In a communication device in a code division multiple access mobile communication system, radio demodulation for demodulating a received signal of a plurality of carrier frequency bands received by each of a plurality of receiving antennas into a spread spectrum signal of a plurality of basebands. And a multiplexer for time-multiplexing the spread spectrum signals of the plurality of basebands, a matched filter for performing a correlation operation between the time-multiplexed baseband spread spectrum signals and a plurality of spread codes, and outputting a correlation value. Among the peak values of the correlation value, a peak detection unit that detects a predetermined number of peak values in order from the one with the highest received power for each of the plurality of spreading codes, and the phase is adjusted to the timing detected by the peak detection unit. And a despreading unit that despreads the baseband spread spectrum signal with the spread code. Communication device comprising and. 11. The communication device according to claim 10, wherein the matched filter includes a plurality of first shift registers for shifting the respective spread codes, and respective spread codes stored in the plurality of first shift registers. And a second shift register for shifting the time-multiplexed baseband spread spectrum signal, and while the first shift register shifts the spread code by one register, The second shift register outputs the baseband spectrum signal multiplexed at the above time to n (n =
The selector shifts the plurality of first shifts while the second shift register shifts the time-multiplexed baseband spread spectrum signal by one register. A communication device which switches and outputs each spreading code stored in a register. 12. A communication device in a code division multiple access mobile communication system, comprising: a despreading unit for despreading a received signal at a plurality of designated timings; and a despreading unit for despreading the received signal at the plurality of timings. And a Rake combining unit for Rake combining the received signals, wherein the despreading unit receives the timing and generates a plurality of spreading codes respectively, and a plurality of code generators that generate the spread codes. A multiplexer that time-multiplexes each spreading code, a register that stores the correlation value between the received signal and the time-multiplexed spreading code for each spreading code, and the multiplication of the received signal and the time-multiplexed spreading code. Add the multiplier to perform and the correlation value stored in the register that stores the correlation value between the multiplication value output from the multiplier and the spreading code that has been multiplied. Communication apparatus characterized by having an adder for. 13. The communication device according to claim 12, wherein the plurality of spreading codes are spreading codes assigned to a plurality of terminals. 14. The communication device according to claim 12, wherein the plurality of spreading codes are spreading codes assigned to different base stations or different sectors. 15. A communication device in a code division multiple access mobile communication system, comprising: a despreading unit for despreading a received signal at a plurality of designated timings; and a despreading unit for despreading the received signal at the plurality of timings. The despreading unit includes a Rake combining unit for Rake combining the received signals, the despreading unit receiving a code generator, a plurality of status registers for storing code data input to the code generator, and receiving the specified timing. And a correlation value between the received signal and the time-multiplexed spread code, and a multiplexer for time-multiplexing each spread code generated by setting the code data stored in the status register in the code generator. A register that stores each spreading code, a multiplier that multiplies the received signal by the time-multiplexed spreading code, and a register that outputs from the multiplier. Communication device, characterized in that it comprises an adder for adding the multiplied value and the correlation values stored in the register for storing a correlation value between spreading code described above were carried out multiplications. 16. A communication device in a code division multiple access mobile communication system for transmitting and receiving a signal modulated by a quaternary phase modulation system, wherein a received signal of a plurality of carrier frequency bands received is spread spectrum of a plurality of base bands. A radio demodulation unit that demodulates an in-phase component signal (I signal) and a quadrature component signal (Q signal) that are signals, a multiplexer that time-multiplexes the I signal and the Q signal, and the time-multiplexed I signal and The correlation calculation between the Q signal and the I code that spreads the I signal and the Q code that spreads the Q signal is performed, and the matched filter that outputs the correlation value, and the peak value of the correlation value that has the highest received power The peak detection unit that detects a predetermined number of peak values in order from the one, and the spreading code that matches the phase with the timing detected by the peak detection unit. Communication apparatus characterized by having a despreading section for despreading the spread spectrum signal de. 17. The communication device according to claim 16, wherein the received power is ((I signal × I code) + (Q signal × Q code)) 2 + ((I signal × Q code) − (Q signal × A communication device characterized by being obtained by I code)) 2. 18. The communication device according to claim 16, wherein the matched filter includes a first shift register that shifts the I code, a second shift register that shifts the Q code, the I code, and the I code. It has a selector for switching and outputting a Q code, and a second shift register for shifting the time-multiplexed I signal and Q signal, wherein the first shift register outputs the I code and the second shift register. While shifting the Q code by one register, the third shift register shifts the I and Q signals multiplexed by two registers by the two registers, and the third shift register is multiplexed by the three times. While shifting the I and Q signals by one register, the selector
A communication device, wherein the I code and the Q signal are switched and output. 19. The communication device according to claim 16, wherein the despreading unit receives the timing and generates an I code, an I code generator and a Q code generator that generate a Q code, and the I code. A multiplexer that time-multiplexes the I code and the Q code generated from the generator and the Q code generator, a first register that stores a correlation value between the I signal and the I code, the Q signal and the Q signal A second register for storing the correlation value with the code, a third register for storing the correlation value with the I signal and the Q code, and a fourth register for storing the correlation value with the Q signal and the I code. Register, a multiplier for multiplying the time-multiplexed I signal and Q signal with the time-multiplexed I code and Q code, and a multiplication value output from the multiplier and a register corresponding to the multiplication value. Is added to the correlation value stored in Communication device; and a calculation unit. 20. The communication device according to claim 16, wherein the despreading unit stores a code generator, a first status register for storing I code data input to the code generator, and Q code data. A multiplexer for sequentially switching and setting the I code data and the Q code data in the code generator in response to the second status register for storing and the designated timing, and a correlation value between the I signal and the I code. A first register for storing, a second register for storing a correlation value between the Q signal and the Q code, a third register for storing a correlation value for the I signal and the Q code, and the Q register A fourth register for storing a correlation value between the signal and the I code, a multiplier for multiplying the time multiplexed I signal and Q signal by the time multiplexed I code and Q code, and the multiplier Squared output from Communication device, characterized in that it comprises an adder for adding the correlation values stored in the register corresponding to the value and the multiplication value. 21. A communication device in a code division multiple access mobile communication system, comprising: a first multiplexer for switching and outputting a plurality of transmission data; a second multiplexer for switching and outputting a plurality of spreading codes; A multiplier for multiplying the output from the multiplexer and the output from the second multiplexer, an output combiner for combining the outputs from the multiplier and the output from the output combiner are D / A converted, and the carrier frequency is obtained. And a wireless modulator that generates the spread spectrum signal of 1.