KR100818284B1 - Wireless communication device, method and system - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless communication apparatus, a method, and a system, comprising: generating replacement data by replacing in-phase components and orthogonal components of transmission data, and transmitting the transmission data and the replacement data, thereby generating a phase of transmission data generated on a transmission path. It is possible to prevent the deterioration of communication quality due to fluctuations and to improve the communication quality.

Description

Wireless communication device, method and system

1 is a block diagram showing the basic configuration of a wireless communication system according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an IQ replacement process in the CIBS-CDMA method according to the first embodiment of the present invention.

FIG. 3A is a diagram showing an ideal received signal state in CIBS-CDMA according to the first embodiment of the present invention.

3B is a diagram illustrating a state in which phase shift of a received signal occurs in the conventional CIBS-CDMA scheme.

4 is a diagram showing the state of a received signal after the IQ replacement process in the CIBS-CDMA system according to the first embodiment of the present invention.

5 is a diagram illustrating a schematic configuration of a wireless communication system according to the present invention.

6 is a block diagram showing the configuration of a wireless communication apparatus according to the first embodiment of the present invention.

7 is a flowchart showing a transmission method in the radio communication method in the first embodiment of the present invention.

8 is a flowchart illustrating a receiving method in a wireless communication method in a first embodiment of the present invention.

9 is a block diagram showing a schematic configuration of a communication control apparatus according to the first embodiment of the present invention.

10 is a block diagram showing the configuration of a wireless communication apparatus according to a second embodiment of the present invention.

Fig. 11 is a diagram showing the evaluation result by calculator simulation in the second embodiment of the present invention.

12A to 12C are diagrams showing an example of the function of a transmitting side interleaver according to the present invention.

13 is a diagram showing the basic configuration of a wireless communication system according to a third embodiment of the present invention.

14 is a block diagram showing the basic configuration of a conventional CIBS-CDMA wireless communication system.

FIG. 15 is a diagram showing diffusion processing and interleaving processing performed on a transmitting side of a conventional CIBS-CDMA system.

16 illustrates multi-user interference in the conventional CIBS-CDMA scheme.

17 illustrates multi-user interference in the conventional CIBS-CDMA scheme.

18 is a diagram illustrating interleaving processing at a transmitting side and deinterleaving processing at a receiving side in the conventional CIBS-CDMA scheme.

19 is a diagram illustrating an example of an error rate characteristic by a conventional CIBS-CDMA scheme.

[Description of the code]

10, 90 wireless communication systems

11, 91 Sending side

12, 92 receiving side

35 IQ Replacement Process

37, 44 IQ replacement indicator

45 IQ replacement decoding processing unit

71 Frequency Domain Equalizer

21 wireless communication devices

22 base stations

23 Higher Control Station

60 Communication Control Unit

61 CPU

Recently, many wireless communication schemes based on repetitive transmission of transmission information data, such as a chip-interleaved block spread-code division multiple access (CIBS) scheme or an interleaved frequency division multiple access (IFDMA) scheme, have been proposed. They have superior communication quality than the existing multiple access method such as DS-CDMA (Direct Sequence-CDMA) in a multi-user environment. This will be described using the CIBS-CDMA method as an example.

Fig. 14 is a block diagram showing the basic configuration of the transmitting side 2 and the receiving side 3 in the wireless communication system 1 applying the conventional CIBS-CDMA scheme. As shown in Fig. 14, in the CIBS-CDMA system, the transmitting side 2 interleaves the spread data transmitted, and the receiving side 3 deinterleaves the received data. These interleaved and deinterleaved replace the order of transmission data or reception data in order to convert multipath user interference due to multipath into interference between symbols of each user.

FIG. 15 is a diagram conceptually showing the contents of the spreading process and the interleaving process performed by the transmitting side 2 of the CIBS-CDMA system. In the CIBS-CDMA system, the transmitting side 2 performs an error correction encoding process on a predetermined cycle with respect to the transmission data, and applies the respective symbols (Data # 0, Data # 1, Data # 2, ...) obtained in this way. The spreader 4 (Fig. 14) sequentially multiplies an orthogonal code (e.g., OVSF: Orthogonal Variable Spreading Factor code (OVS) (# 0 to # SF-1) that is assigned to the user. do.

In the CIBS-CDMA system, the data of each symbol thus obtained is arranged in the interleaver 5 (Fig. 14) with one symbol chip in the direction of "Write in" in the figure. Read out sequentially in the memory so that they are arranged in the direction of " Read out ". Subsequently, a predetermined number of symbols are grouped into one group so that data is read in units of chips in the direction of " Read out " in the figure, and the data lines of the transmission data are replaced (interleaved processing). At this time, the reading of such data is performed a plurality of times for each group, through which transmission data is repeatedly transmitted.

The orthogonal code used in the spreading process may be of any sequence as long as it fully satisfies the orthogonality between the orthogonal codes. In Fig. 15, GI represents a guard interval for reducing interference between groups. These guard intervals are inserted at one group interval.

On the other hand, in the deinterleaver 6 of the receiving side 3, as shown in Fig. 14, the orthogonal codes of the respective symbols are arranged in the direction of "Read out" with respect to the received data, and the data of each symbol is "Write in." The memory is sequentially written in memory so as to be arranged in the direction of ", and then a predetermined number of symbols are made into one group, and data is read in the direction of " Read out " in the orthogonal code unit for each group, before the lines of the received data are interleaved. Replace with the original data line (deinterleave). The despreading processing section 7 on the receiving side 3 performs the despreading process on the received data of the original data line thus obtained.

According to the CIBS-CDMA system, as shown in FIG. 16, which is indicated by the same reference numerals as in FIG. 14, the direct wave (amplitude h1) and the reflected wave (amplitude h2) are added. , D1, D2, ... symbols of transmission data interfere with each other, resulting in symbols X1, X2, X3 .... Since the code sequences themselves do not change, they are orthogonal. There is an advantage that the orthogonality between codes is satisfied, i.e., there is no interference between users in a multipath environment. In FIG. 16, the reflected wave is delayed by one chip with respect to the direct wave, and FIG. 17 shows that orthogonality is satisfied between orthogonal codes even in a multi-user environment.

However, according to the conventional CIBS-CDMA system, there is a problem that it is easily affected by the time variation of the transmission path. The interleaving of the transmission data at the transmitting side and the deinterleaving of the receiving data at the receiving side increases the time interval between columns in the deinterleaver, and consequently reflects the time variation more than the actual variation at reading. Because it can be. This state is shown in FIG.

Referring to FIG. 18, the CIBS-CDMA scheme will be described in detail as follows. In the CIBS-CDMA system, orthogonality between users is obtained by orthogonal codes. 2 Assume a user environment, where user # 1 is given an orthogonal code consisting of four chips: +1, +1, +1, +1, and user # 2 is +1, +1, -1, -1. Assume In this case, the chip refers to one bit of the code. In this case, the receiving side multiplies the orthogonal code of each user by the received signal and integrates the four chip sections to obtain transmission information for each user. However, the difference in the sign between the user # 1 and the user # 2 is the polarity of the third chip and the fourth chip. If the polarity of the third and fourth chips is changed, the user cannot distinguish between them, that is, interference occurs between users (even if the first and second chips are changed).

However, as shown in FIG. 18, if the transmission path time variation of 90 degrees, that is, 1/4 cycle, occurs in the depth of the interleaver (that is, the variation that becomes 1 cycle when 4 columns are transmitted), The order is changed by the interleaving process, and the signal sent to the despreading unit becomes a signal that changes by 90 degrees per chip. That is, a high speed phase change occurs. As a result, since the third chip already has a phase change of more than 180 degrees, polarity inversion occurs. Since the transmission path is independent of each user, in this case, each user has already become incapable of identifying, i.e., incapable of communicating.

In this example, high-speed time fluctuations are assumed for the sake of understanding, but in practice, high-speed fluctuations are rare. However, there is still a problem that the time interval is compressed by the interleaver / deinterleaver process and the transmission path time fluctuation becomes high in principle.

As described above, even in the CIBS-CDMA system or the IFDMA system in which multi-user interference does not occur, the orthogonality between users is degraded due to the time variation (also called Doppler Spread), and communication quality is deteriorated. It is thought that it is not suitable for operation.

19 is a state of full-load generally referred to as the diffusion rate is 16 and the number of users is 16. FIG. The echo assumes a state of one in the transmission path and assumes an uplink (transmission from the mobile station to the base station) that all users are asynchronous. In the drawing, if two-branch reception diversity is applied, the driving speed of 300 km / h can be achieved up to 150 km / h per hour, compared to being able to achieve ^{4x10 -2} or less, which is a standard for obtaining an error rate improvement effect by introducing an error correction code. It can be seen that the speed cannot be achieved. That is, from Fig. 19 showing the results of the calculator simulation, it is concluded that communication is impossible in a high-speed mobile environment such as a high-speed train traveling at 300 km / h per hour.

The technical problem to be solved by the present invention is to solve the problem that the communication quality caused by the phase shift caused by the transmission path of the transmission data is deteriorated, so that the communication quality can be maintained even when the wireless communication device is in a high speed mobile environment. An apparatus, method and system are provided.

Wireless communication apparatus according to the present invention for solving the above technical problem is a replacement unit for generating replacement data by replacing the in-phase component and orthogonal component of the transmission data; And a transmitter for transmitting the transmission data and the generated replacement data.

According to another aspect of the present invention, there is provided a wireless communication apparatus including: a receiving unit for receiving transmission data and receiving replacement data which is data in which in-phase components and orthogonal components of the transmission data are replaced; And a decoded data generator for generating decoded data by replacing the in-phase component and the orthogonal component of the replacement data and synthesizing with the received transmission data.

Wireless communication system according to the present invention for solving the above technical problem is a replacement unit for generating replacement data by replacing the in-phase component, orthogonal component of the transmission data; And a transmitting unit which transmits the transmission data and the generated replacement data; A receiving unit which receives the transmission data and the replacement data; And a decoded data generator for generating decoded data by replacing the in-phase component and the orthogonal component of the replacement data and synthesizing with the received transmission data.

The wireless communication method according to the present invention for solving the technical problem comprises the steps of generating replacement data by replacing the in-phase component and orthogonal component of the transmission data; And transmitting the transmission data and the generated replacement data.

According to another aspect of the present invention, there is provided a method of wireless communication, the method comprising: receiving transmission data and receiving replacement data which is data in which in-phase components and orthogonal components of the transmission data are replaced; And after replacing the in-phase component and the quadrature component of the replacement data, generating decoded data by synthesizing with the received transmission data.

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

(1) First embodiment

(1-1) The wireless communication method according to this embodiment

FIG. 1 shows a basic configuration of a transmitting side 11 and a receiving side 12 of the wireless communication system 10 according to the first embodiment of the present invention in CIBS-CDMA. Compared with the above-described conventional CIBS-CDMA wireless communication system 1 (Fig. 14), one of the features of the CIBS-CDMA system according to the present embodiment is that the transmitting side 11 is used for transmitting data I (In-phase: in-phase), Q (Quadrature-phase: orthogonal) in-phase (I) and orthogonal (Q) component replacement processing (hereinafter referred to as IQ replacement processing) is carried out, the receiving side 12 An IQ replacement process is performed on the received data and an addition process is performed.

The meaning of performing the IQ replacement process lies in the phase shift. It is expressed by the following formula. If the transmission complex signal that changes in T time period (T is, for example, T = 16t in symbol time) is X (t), X (t) is represented by the following equation.

X (t) = I _tx (t) + jQ _tx (t) (1)

Appears as

Here, I _tx (t) is an in-phase component of transmission information, and Q _tx (t) is an orthogonal component of transmission information. This equation (1) uses exponential notation

X (t) = | α (t) | e^{j θ (t)} (2)

It can also be expressed as Expressions (1) and (2) are identical except that the expression methods are different. Where || is the absolute value symbol, | α (t) | is the amplitude (= √ (I2 + Q2)), and θ (t) is the angle information (eg, atan (Q, I)) that varies with the transmission information. to be.

If I and Q signals are replaced here, (1) is

ISM (X (t)) = Q _tx (t) + jI _tx (t) (3)

Changes as Here, ISM () is a function indicating the IQ replacement process. If you modify (3) to approach (1),

ISM (X (t)) = Q _tx (t) + jI _tx (t)

= j (I _tx (t) -jQ _tx (t)) (4)

Can be expressed as In exponential notation,

ISM (X (t)) = j | α (t) | e^{-jθ (t)} (5)

Can be expressed as It can be seen from Equation (5) that the IQ replacement process means that the phase shift of 90 degrees (multiplication of = j) and the advancing direction of the phase angle are reversed with respect to the signal which has not been replaced.

Next, a phase change term due to a phase change between a transmission path or a transceiver is added. In the exponential representation, the phase variation can be expressed by multiplication. Therefore, if the phase variation is? Ch (t), then the received signal y (t) affected by this is expressed by the following equation.

y (t) = j | α (t) | e^{-jθ (t)}e^{j θ ch (t)} (6)

Becomes If this signal is received and the receiving side performs IQ replacement process, the ISM () function, which is the IQ replacement process, means j phase shift and inversion of the phase rotation direction.

ISM (y (t)) = | α (t) | e^{j θ (t)}e^{-jθ ch (t)} (7)

Becomes This equation (7) means that transmission information without performing IQ replacement processing can be restored and the transmission path phase shift is in the opposite direction.

As a result, if the sum of the signal subjected to the IQ replacement process and the signal not performed is obtained, the following equation is obtained.

y (t) + ISM (y (t + 1)) = | α (t) | e ^{j θ (t)} (e ^{j θ ch (t)} + e ^{-jθ ch (t + 1)} )

= | α (t) | e ^{j θ (t)} {cosθ _ch (t) + jsinθ _ch (t) + cosθ _ch (t + 1) -jsinθ _ch (t + 1)}

= (α (t) | e ^{j θ (t)} {cosθ _ch (t) + cosθ _ch (t + 1)} (8)

Becomes

Here, α (t) and θ (t) representing the transmission information signal can be regarded as the same without being changed in the time of y (t) and y (t + 1) if T time together elapses. In addition, at a very small time, θ _ch (t) and θ _ch (t + 1) hardly change, so the imaginary component cancels out, resulting in the expression (8). It can be seen from Equation (8) that the sum of ISM () execution and non-execution is projected on the real axis, so that the phase shift term disappears and only the amplitude shift occurs. This state is as shown in FIG.

This result shows that it is possible to avoid the polarity change occurring in the user identifier (= orthogonal code) due to the phase shift described above as a problem of the prior art. Equation (8) is not a complete user-orthogonal signal processing because amplitude fluctuations remain, but has a great effect in wireless communication access methods such as CIBS-CDMA and IFDMA.

In Equation (8), the correspondence in the case where the initial phase term occurs will be described later in the description of the second embodiment of the present invention.

An object of the present invention is to improve orthogonality between users in a user environment of an access method such as CIBS, IFDMA, or a variant thereof. In the CDMA-based access method, unlike the conventional DS-CDMA (the third generation mobile communication method called FOMA or cdma WIN (both trade names)), it aims at perfect orthogonality between users. In the case of directing orthogonality between users, as in the conventional DS-CDMA, phase compensation by signal processing after user signal extraction (= despreading process) is incomplete, and if the user-to-user identifier (CIBS-CDMA) before user signal extraction, Full orthogonality of orthogonal codes and IFDMA orthogonal frequencies must be satisfied.

In this case, the phase shift of the transmission path or the phase shift between the transceivers should be compensated before the despreading process. As a means of compensating for the phase shift before user extraction, a method called delay detection is common. For example, in delay detection, conjugate complex multiplication is performed with a signal before one symbol, and phase shift of a transmission path is reduced. Hereinafter, it demonstrates using a formula. If the received signal is s (t), s (t + 1), the delay detection signal is

s (t) * s ^* (t + 1) = e ^{j (θ data (t) + θ ch (t))} + e ^{-j (θ data (t + 1) + θ ch (t + 1))}

= e^{j Δθ data (t)} (9)

Appears as

In order that Δθ _{data (t)} indicates the transmission information, a process such as differential encoding is performed in advance on the transmitting side, and the transmission information is loaded in the difference. Clearly from Equation (9), the phase shift of the transmission path is lost or reduced. Due to these advantages, delay detection is generally used in the second generation of mobile communication.

However, this delay detection has a problem. First of all, it is difficult to apply the multi-value modulation technique and the deterioration of characteristics is remarkable. Since the transmission information is given to the phase term as in Equation (9), there is a significant deterioration in the multi-value modulation technique in which information also exists in an amplitude called 16QAM.

In addition, as another problem, since delay detection basically assumes a single user environment, there is a problem in application before user extraction. S (t) in (9) is

s (t) = s ₁ (t) + s ₂ (t) + s ₃ (t) +. + s _N (t) (10)

As can be easily seen when applied to the N-user environment, a cross-term occurs at the conjugate complex multiplication to increase the signal that can be seen as noise.

From the above results, delay detection is practically not applicable to orthogonalization between users before despreading.

However, according to the CIBS-CDMA system according to the present embodiment, even when a phase shift occurs in the abnormal reception signal (= transmission signal) (Fig. 3A) (Fig. 3B), by changing the amplitude variation as shown in Fig. 4, Orthogonalization can be aided.

Also, since Equation (8) can be applied to any amplitude term | (alpha) (t) |, this embodiment can also be applied to 16QAM transmission involving amplitude fluctuation described above.

16QAM modulation is essential for the next generation of high-speed mobile communication (= increase in bit rate per unit time), and it is very effective such that multi-value modulation can be applied before user extraction and phase shift is suppressed.

(1-2) A wireless communication system according to the present embodiment.

Next, a detailed configuration of the wireless communication system to which the CIBS-CDMA system according to the present embodiment is applied will be described. In this description, it is assumed that the timing of execution of the IQ replacement process is obtained by an instruction from a higher management station described later for the sake of understanding, but this is only an example and this is unnecessary if it is uniquely defined between the transceivers.

5 is a diagram illustrating a wireless communication system according to the present invention. The radio communication system 20 is composed of a plurality of radio communication apparatuses 21 (10), a plurality of base stations 22, and an upper control station 23. FIG.

7 and 8 illustrate, in a flowchart, a wireless communication method in a first embodiment of the present invention. 6 to 8, the wireless communication method according to the first embodiment will be described below.

The wireless communication device 21 is configured as shown in Fig. 6, and the user's speech is collected by the microphone 30, and the obtained voice signal S1 is input to the signal processor 31. (Step 100 )

The signal processor 31 performs predetermined signal processing such as analog / digital conversion on the supplied voice signal S1 and inputs it to the QPSK modulator 32 as a digital voice signal S2. In addition, the QPSK modulator 32 modulates the supplied digital voice signal S2 by QPSK, and outputs the QPSK modulated signal S3 obtained through the diffusion processing unit 33 (step 110).

At this time, the orthogonal code generator 34 transmits and receives the spreading rate SF designated by the upper control station 23 (FIG. 5) and the code number of the orthogonal code assigned to the user as the orthogonal code designation information D1. 39). Then, the orthogonal code generation unit 34 generates a corresponding orthogonal code of the diffusion rate SF based on the orthogonal code designation information D1 and outputs it to the diffusion processing unit 33. The diffusion processing unit 33 multiplies the orthogonal code by the QPSK modulation signal S3 to spread the QPSK modulation signal S2, and outputs the obtained diffusion processing signal S4 to the IQ replacement processing unit 35. 120 steps)

In addition, the IQ replacement processor 35 performs an IQ replacement process as described in detail with reference to FIG. 1 to the input spread signal S4, and outputs the signal S5 obtained through the interleaver 36. Step 130)

At this time, the IQ replacement timing designation information D2 specified by the upper control station 23 (FIG. 5) is input to the IQ replacement instruction unit 37 from the transmission / reception unit 39. Then, the IQ replacement instruction unit 37 repeatedly generates a timing specified based on the IQ replacement timing designation information D2 in synchronization with the diffusion processing signal S5, and sends these timings to the IQ replacement processing unit 35. In this way, the IQ replacement processing section 35 executes the IQ replacement processing at the timing given from the IQ replacement indicating section 37 with respect to the spread signal S4 provided from the diffusion processing section 33 under the control of the transmission / reception section 39, for example. do. The IQ replacement processor 35 outputs the generated replacement signal S5 to the interleaver 36.

The interleaver 36 generates a scrambled signal S6 by changing the time relationship between the spread signal and the signal transmitted substantially to a predetermined rule and outputs it to the guard interval insertion unit (+ GI) 38 (step 140).

The guard interval inserting unit 38 sequentially inserts the guard interval for every predetermined symbol of the scramble signal S6, and outputs the GI insertion scramble signal S7 obtained through this to the transceiver unit 39 (step 150).

The transceiver 39 performs predetermined signal processing such as predetermined filter processing for limiting the band and up-converting processing of raising the frequency of the GI insertion scramble signal S7 with respect to the GI insertion signal S7. The transmission signal S8 thus obtained is transmitted through the antenna 40 (step 160).

On the other hand, the radio communication apparatus 21 (FIG. 5) receives the transmission signal S10 transmitted by relaying the base station 22 at the call partner side through the antenna 40 at the transceiver 39. The transmission / reception unit 39 performs predetermined signal processing such as down-conversion processing on the transmission signal S10, and outputs the received signal S11 obtained through this to the guard interval removal unit (-GI: 41). (200 steps)

In addition, the transceiver 39 outputs the above-described orthogonal code designation information D1 transmitted from the upper control station 23 through the base station 22 to the orthogonal code generator 47 separately from the above. The above-mentioned IQ replacement timing designation information D2 transmitted from the upper control station 23 through the base station 22 is output to the IQ replacement instruction unit 44.

The guard interval removal unit 41 removes the guard interval from the received reception signal S11 and outputs the GI removal reception signal S13 obtained through the deinterleaver 43 (step 210).

The deinterleaver 43 deinterleaves the received interleaved signal S13 as described above with reference to FIG. 1, and outputs the deinterleaved signal S14 obtained through the IQ replacement decoding processor 45. step)

As described above, the IQ replacement instruction unit 44 repeatedly generates the IQ replacement instruction signal at the designated time, based on the IQ replacement execution timing designation information D2 provided from the transceiver unit 39, and the IQ replacement decoding processing unit 45 ) In this way, the IQ replacement decoding processing unit 45 performs the IQ replacement decoding processing on the deinterleaver signal S14 input from the deinterleaver 43 under the control of the transmitting / receiving unit 39 at the timing given from the IQ replacement indicating unit 44. Do At this time, the IQ replacement decoding processing means adding the even-numbered and odd-numbered signals after performing the same IQ replacement processing as that of the transmitting side as described in Fig. 1 or (8) and the description thereof. After this processing, the IQ replacement decoding processing unit 45 outputs the decoded signal S15 obtained as a result to the despreading processing unit 46 (step 230).

At this time, the orthogonal code generation unit 47 generates an orthogonal code assigned to the user based on the orthogonal code designation information D1 given from the transmission / reception unit 39 as described above, and generates the orthogonal code to the despreading processor 46. Output In this way, the despreading unit 46 multiplies the spreading signal S15 by the orthogonal code inputted from the orthogonal code generating unit 47 to despread the spreading signal S15, and thereby obtains the QPSK modulated signal S16. ) Is output to the QPSK demodulator 48 (step 240).

The QPSK demodulator 48 performs QPSK decoding on the received QPSK modulated signal S16, and outputs the digital voice signal S17 obtained through the signal to the signal processor 49. The signal processor 49 then outputs the digital voice signal S17. Predetermined signal processing such as digital / analog conversion processing is performed on the input digital voice signal S17, and the voice signal S18 obtained through this is sent to the speaker 50 (step 250).

As a result, the voice based on the voice signal S18 is output from the speaker 50. In this way, the wireless communication apparatus 21 is configured to transmit the voice of the user to the call counterpart, and to output the voice transmitted from the call counterpart to the speaker 50 (step 260).

9 shows the configuration of the communication control device 60 that controls communication between the radio communication devices 21 installed in the upper control station 23 (FIG. 5). As shown in Fig. 9, the communication control device 60 includes a CPU (Central Processing Unit) 61 which manages operation control of the entire communication control device 60, and a ROM (Read Only Memory) in which various control programs are stored. 62, a RAM (Random Access Memory) 63 as a work memory of the CPU 61, a storage device 64 such as a flash ROM in which various application software are stored, and the CPU 61 are each base station 22 (Fig. 5) and a communication processing unit 65 as an interface for communicating via a telephone line or a wireless communication line are connected to each other via a bus 66.

(1-3) Operation and Effects of the Embodiment

In the above configuration, the transmitting side performs IQ replacement processing and transmits, and the receiving side executes the IQ replacement processing, and adds them (the IQ replacement processing and the non-replacement processing).

According to such a wireless communication system, the phase shift in a phase shift environment can be lost by calculating the sum of the signal that has undergone the IQ replacement processing and the signal that has not been executed on the receiving side. As a result, it is possible to replace the phase shift with respect to the spreading code which is the user identifier (realized by = ± 1) by the amplitude shift, and the orthogonality between the users can be improved.

Therefore, by adopting the wireless communication system according to the present embodiment, phase shift, which is a weak point of the CIBS-CDMA system, can be reduced, and the communication quality can be improved as compared with the conventional wireless communication system.

And by improving the communication quality in this way, it becomes possible to reduce the required transmission power required before the radio wave reaches the reception side. This means that the battery of the wireless communication device 21 is sustained for a long time when the rising line from the wireless communication device 21 to the base station 22 is considered, and that it is possible to save power of the infrastructure when considering the falling line. it means. In addition, if the application does not require power saving in particular, it means that the radio wave transmission distance is extended, that is, the service area is extended.

(2) Second Embodiment

(2-1) Wireless communication method according to this embodiment

In the first embodiment, the case where the present invention is applied to an environment in which the initial phase is not considered or the phase change is not severe has been described. However, when the phase change is severe, the configuration of the first embodiment causes a decrease in the amplitude level, and the improvement effect is less. However, even in this case, it is possible to prevent deterioration by effectively arranging general phase compensating means. The second embodiment shows an effective implementation of the present invention which makes this possible.

FIG. 10 shows a configuration of a radio communication apparatus 70 according to a second embodiment of the present invention, in which corresponding parts to FIG. 6 have the same reference numerals. As shown in Fig. 10, another part of the second embodiment is the presence of a frequency-domain equalization unit (FDE) (FDE). The frequency domain equalizer 71 compensates for amplitude and phase variations in the transmission path in the frequency domain. This technique works in a multipath environment.

The frequency domain equalizer 71 performs a predetermined frequency domain equalization process based on a minimum mean square error (MMSE) norm for improving the bit error rate characteristic with respect to the input GI removal received signal S12. Then, the equalized signal S13 obtained through this is output to the deinterleaver 43. This frequency domain equalization process gives a compensation coefficient specific to the transmission path of the user to extract. Therefore, in the base station reception in which multiple users are added and input, even if the amplitude and phase compensation of the target user can be performed, the other user is given an irrelevant coefficient so that the amplitude and phase of the other users are bent and disturbed.

As described above, in the present invention, an amplitude change occurs according to the amount of phase shift. Therefore, the amplitude level is reduced for other user signals given the large phase shift by the frequency domain equalizer 71 described above. Reducing this amplitude level means less influence on the target user. Since the phase change is a random variable, it cannot be said that the amplitude level is always reduced. However, since the level is always reduced when the phase change occurs, the amount of interference by other users is less than that of the case where the present invention is not used. Communication quality is always improved.

On the other hand, the frequency domain equalizer 71 acts on the target user, performs multipath compensation, and performs phase compensation. That is, the signal of the target user after passing through the frequency domain equalizer 71 becomes a signal whose initial phase and phase variation are compensated to some extent. As a result, by applying the present invention, it is possible to compensate for the residual phase change that could not be compensated in the FDE.

As described above, when applying the present invention, it is preferable to perform phase compensation (preferably amplitude compensation) at the front end of the IQ replacement decoding processing unit 45 in the reception processing. Although the frequency domain equalizer 71 is used in the above example, any phase compensation technique that satisfies the present description is irrelevant. For example, a conventional equalizer in the time domain may be used.

(2-2) Configuration of Wireless Communication System According to Present Embodiment

10 is a block diagram showing a configuration of a wireless communication apparatus according to a second embodiment of the present invention. This radio communication apparatus is configured similarly to the radio communication apparatus according to the first embodiment except that the above-described frequency domain equalizer 71 is applied as the transmission path variation compensation method.

FIG. 10 shows a detailed configuration of a wireless communication apparatus in a wireless communication system according to a second embodiment of the present invention, in which corresponding parts to FIG. 6 are denoted by the same reference numerals. This difference between FIG. 10 and FIG. 6 lies in the receiver. In the reception system, the reception signal of the radio band received by the antenna 40 is down-converted according to the base band by the transmission / reception unit 39 and output to the guard interval removal unit 41.

The guard interval removal unit 41 removes the guard interval from the received reception signal S11 and outputs the GI removal reception signal S12 obtained through this to the frequency domain equalizer FDE 71.

The frequency domain equalizer 71 performs a predetermined frequency domain equalization process based on a minimum mean square error (MMSE) norm for improving the bit error rate characteristic of the received GI removal received signal S12. The obtained scramble signal S13 is output to the deinterleaver 43.

The deinterleaver 43 performs a deinterleave process that is uniquely determined in the wireless communication system (to send and receive) to the frequency equalized signal S13, and decodes the deinterleave signal S14 obtained through the IQ replacement decoding. Output to the processing part 45.

The IQ replacement decoding processing unit 45 receives the timing at which the IQ replacement processing is executed by the IQ replacement indicating unit 44 as in the first embodiment described above, and replaces the IQ signal of the reception signal S14 at the specified timing. do. Thereafter, the signal S15 obtained by calculating the sum of the signal which has not been subjected to the IQ replacement processing and the signal which has been subjected to the IQ replacement processing is output to the despreading processing section 46.

At this time, the orthogonal code generation unit 47 generates an orthogonal code assigned to the user based on the orthogonal code designation information D1 given from the transmission / reception unit 39 as described above, and generates the orthogonal code to the despreading processor 46. Output In this way, the despreading processor 46 multiplies the spreading signal S15 by the orthogonal code input from the orthogonal code generating unit 47, despreads the spreading signal S15, and obtains the QPSK modulated signal ( S16) is output to the QPSK demodulator 48.

The QPSK demodulator 48 performs QPSK decoding on the input QPSK modulated signal S16, and outputs the digital voice signal S17 obtained through the signal to the signal processor 49. Then, the signal processing unit 49 performs predetermined signal processing such as digital / analog conversion processing on the input digital voice signal S17, and sends the obtained voice signal S18 to the speaker 50. As a result, the sound based on the sound signal S18 is output from the speaker 50.

In this way, the wireless communication device 70 is configured to transmit the voice of the user to the call counterpart and output the voice transmitted from the call counterpart to the speaker 50.

Here, FIG. 9 shows a configuration of a communication control device 80 that controls communication between the radio communication devices 21 installed in the upper control station 22 (FIG. 5). This communication control device 80 is configured similarly to the communication control device 60 according to the first embodiment.

(2-3) Operation and Effects of the Embodiment

In the above configuration, the wireless communication system also performs the IQ replacement process at the predetermined timing on the transmitting side, and also the sum of the signal which has performed the IQ replacement process at the same timing on the receiving side, and the signal which has not been replaced. Calculate

However, there is a frequency domain equalizer (FDE) 71 that corrects the phase shift between the transmission line or the transceiver before the IQ replacement process is executed on the receiving side. This frequency domain equalizer corrects the phase shift (and amplitude fluctuation) of the user to be extracted, and this correction makes it possible to minimize the amplitude attenuation resulting from the IQ replacement process. In addition, the residual phase shift damaged by the frequency domain equalizer 71 is compensated for in the phase-amplitude conversion by the IQ replacement process. In addition, the phase shift that the frequency domain equalizer 71 gives to other users is reduced in amplitude by the IQ replacement process, thereby contributing to the reduction of other user interference amount.

Therefore, by adopting the wireless communication system according to the present embodiment, the phase shift, which is a weak point of the CIBS-CDMA system, can be reduced, so that the communication quality can be improved compared to the conventional wireless communication system.

FIG. 11 is a diagram showing the results of evaluating a second embodiment of the present invention by a calculator simulation. Fig. 11 compares the communication quality between CIBS-CDMA in the prior art and CIBS-CDMA in the second embodiment of the present invention. As shown in the figure, it can be seen that 4 × 10 ^{−2, which} is a criterion of communication quality that has been a problem in the prior art, is achievable, and that an error correcting code is used in combination with a communication state.

By improving the communication quality in this way, it becomes possible to reduce the required transmission power required before the radio wave reaches the reception side. This means that the battery of the wireless communication device 21 is sustained for a long time in consideration of the rising line from the wireless communication device 21 to the base station 22, and that it is possible to save power of the infrastructure when considering the falling line. do. In addition, if the application does not require power saving in particular, it means that the propagation distance is extended by that much, either can obtain an effective effect.

(3) Third embodiment

In the above-described first and second embodiments, by transmitting the same signal, the number of transmission information bits per unit time is reduced. And the third embodiment of the present invention is a configuration for complementing this.

12C illustrates an interleaver according to a third embodiment of the present invention. 12A to 12C show an example of a functional concept of the transmitting interleaver. FIG. 12A shows an execution image of the IQ replacement process in the first or second embodiment of the present invention, and FIG. 12B is an approach from another concept, in which the execution of the IQ replacement process is applied in the diffusion code direction. In Fig. 12C, the distinction between the signals to be multiplexed is assumed to use a code.

For example, assume that the codes are +1, +1 for transmission data D0 to D3, and +1 and -1 for D4 to D7. If the first D0 to D3 (or D4 to D7) are in one mass, since there are two types of transmission blocks, the +1 and +1 (or +1, -1) are assigned to each block. The receiving side performs despreading using their codes. In addition, since the actual signal is supplied to the interleaver in the added state as shown in Fig. 12C, it is not possible to distinguish D0 to D3 and D4 to D7 inside the interleaver.

FIG. 13 shows an example of the configuration of the wireless communication system 90 according to the third embodiment of the present invention, in which the same reference numerals are given to the corresponding portions of FIG. The other thing compared with FIG. 1 is the structure which supplements that the transmission information bit by IQ replacement process is reduced by half. Hereinafter, it demonstrates as follows, comparing with FIG.

Since the information signal " Data " transmitted in FIG. 1 is halved in comparison with CIBS-CDMA of the prior art, in FIG. 13, Data # 1 and Data # 2 are described in the transmission side 91. FIG. If the data amount in CIBS-CDMA of the prior art is 1, the data amount in FIG. 1 is 0.5, and Data # 1 and Data # 2 in FIG. 13 are 0.5 respectively. Therefore, in FIG. 13, the same amount of transmission information as in the prior art is transmitted.

Since the spreading units 93A and 93B on the transmitting side 91 are user identifiers, the same spreading codes are multiplied to each of Data # 1 and Data # 2. Thereafter, code multiplexing is performed to distinguish Data # 1 and Data # 2. Here, the adders 94A and 94B perform sign multiplexing. Depending on whether the inputs to the adders 94A and 94B are "+" or "-", the sign is multiplied by +1 or multiplied by -1. We are doing multiplexing. Therefore, in FIG. 13, Data # 2 is spread with the codes of +1 and -1, and Data # 1 is spread with the codes of +1 and +1. These spread signals are added by the adders 94A and 94B, and one of them is replaced by the IQ replacement processor 95. Operations from the interleaver 96 to the deinterleaver 97 in the receiving side 92 are the same as those of the first and second embodiments of the present invention and will be omitted.

The output of the deinterleaver 97 is different from that of the IQ replacement processing, and the processing method and the like are different. This is because the spreading code is multiplied by each of Data # 1 and Data # 2. The despreading process is performed in the adders 98A and 98B. Like the adder on the transmission side, subtraction and addition are effectively combined again, which is equivalent to multiplying -1 and +1. The halfway of transmission data can be prevented by the above method.

According to the present invention, in addition to transmitting the transmission data, the replacement data generated by replacing the in-phase component and orthogonal component of the transmission data is transmitted, and when the transmission data and the replacement data are received, the in-phase component and orthogonal component of the replacement data are received. After the replacement, the decoded data or the decoded signal is generated by adding up the received transmission data, thereby preventing the degradation of communication quality caused by the phase shift caused by the transmission path of the transmission data.

In addition, when it is desired to maintain a constant communication quality, power savings can be realized for a wireless communication system, such as reducing the transmission power required for radio waves to reach the receiving side wireless communication device, or extending the radio wave reach distance. It's effective.

Claims (16)

A replacement unit generating replacement data by replacing in-phase and quadrature components of the transmission data; And And a transmitting unit which transmits the transmission data and the generated replacement data. According to claim 1, The replacement unit generates replacement data by replacing in-phase and quadrature components of the transmission data at predetermined intervals, And the transmitting unit transmits the transmission data and the generated replacement data at the predetermined period. The method of claim 2, And a multiple processing unit for dividing the transmission data into two or more and multiplying each of the divided transmission data by a predetermined code to execute code division multiplexing. A receiving unit for receiving the transmission data and receiving replacement data which is data in which in-phase components and orthogonal components of the transmission data are replaced; And And a decoded data generator for generating decoded data by replacing the in-phase component and the orthogonal component of the replacement data and synthesizing with the received transmission data. The method of claim 4, wherein And an equalizer for compensating for the phase variation occurring in the transmission path with respect to the transmission data received by the receiver and the replacement data received by the receiver. The method according to claim 4 or 5, And a demodulator configured to generate a voice signal by modulating the decoded data generated by the decoded data generator. A replacement unit generating replacement data by replacing in-phase and quadrature components of the transmission data; And a transmitting unit which transmits the transmission data and the generated replacement data; A receiving unit which receives the transmission data and the replacement data; And a decoded data generator for generating decoded data by replacing the in-phase component and orthogonal component of the replacement data and combining the received data with the received transmission data. (a) generating replacement data by replacing in-phase and quadrature components of the transmission data; And (b) transmitting the transmission data and the generated replacement data. The method of claim 8, wherein step (a) (a1) dividing the transmission data into two or more, and multiplying each of the divided transmission data by a predetermined code; And (a2) synthesizing the transmission data multiplied by the code, and generating replacement data by replacing in-phase and quadrature components of the synthesized transmission data. The method of claim 8, In step (a), replacement data is generated by replacing in-phase and quadrature components of the transmission data at predetermined intervals, The step (b) is characterized in that the step of transmitting the transmission data and the replacement data in the predetermined period. (a) receiving transmission data and receiving replacement data which is data in which in-phase components and orthogonal components of the transmission data are replaced; And (b) generating decoded data by replacing the in-phase component and orthogonal component of the replacement data and synthesizing with the received transmission data. The method of claim 11, wherein And compensating for the transmission data and the replacement data, the phase variation occurring in the transmission path. The method of claim 11 or 12, (c) modulating the decoded data to generate a voice signal. A replacement unit generating replacement data by replacing in-phase and quadrature components of the transmission data; And A transmission system including a transmission unit for transmitting the transmission data and the generated replacement data; A receiving unit for receiving the transmission data and receiving replacement data which is data in which in-phase components and orthogonal components of the transmission data are replaced; And And a decoding system including a decoded data generating unit for generating decoded data by replacing the in-phase component and orthogonal component of the replacement data and synthesizing with the received transmission data. The method of claim 14, And an equalizer installed at a front end of the decoded data generator, the equalizer configured to compensate for a phase change in a transmission path with respect to the received transmission data and the received replacement data. The method of claim 14, And a multiple processing unit for dividing the transmission data into two or more and multiplying each of the divided transmission data by a predetermined code to execute code division multiplexing.

Images