JPH10271091A - Spread spectrum radio communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a communication equipment to conduct plural sets of 1:1 communication by adopting a time division method for the spread spectrum communication system. SOLUTION: A communication equipment is provided with a reception section 2 that receives a radio communication signal by a spread spectrum modulation system from plural other stations based on a time division format where a 1-frame period consists of a prescribed number of time slots, a time slot discrimination section 6 that discriminates a current available state of time slots based on a reception demodulated output Do, a time slot decision section 7 that decides a time slot used for acknowledgement transmission by a communication opposite station while transmission of its own station to a time slot at a required position based on the discrimination, a memory section 8 that stores data such as decided time slot position, a transmission section 3 that transmits required data by a radio communication signal adopting the spread spectrum modulation system through its own station time slot, and a control section 10 that controls the time slot discrimination section 6 and the transmission section 3 or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spread spectrum wireless communication apparatus, and more particularly, to a communication apparatus capable of multiplex communication using a time division system in a spread spectrum communication system.

[0002]

2. Description of the Related Art Conventionally, multiplex communication techniques include frequency division multiplexing (FDM), time division multiplexing (TDM), and code division multiplexing (CDM). Code division multiplexing (C
As a device belonging to the DM) system, there is a spread spectrum system. In the spread spectrum system, a plurality of combinations of wireless communication can be performed within the same frequency band by using different spreading codes. Further, the spread spectrum method is relatively resistant to interference on a transmission line, and therefore has a feature that the degree of error occurrence in a transmission signal is smaller than that of frequency division multiplexing (FDM) or time division multiplexing (TDM). However, when data with a large amount of information such as an image is communicated by the above spread spectrum method, it is desirable to use a spread code having a short code length, but the spread code having a short code length is limited. (11, 15, 31 chips, etc.). On the other hand, when communication with a large amount of information is performed using a spread code having a long code length (eg, 63 or 127 chips), a wide frequency band is required.

[0003]

Therefore, even in a spread spectrum communication system having a feature of being resistant to interference, if multiplex communication is performed in a limited frequency band, the code length is short as described above. Due to the limited spreading codes, the number of wireless stations that can communicate simultaneously is limited. For this reason, as a method of increasing the number of wireless stations based on the spread spectrum method, it is conceivable to adopt a time division method in the spread spectrum method. However, in order to adopt this time division method, it is essential to install a dedicated base station for managing time slots. If it is desired to simply configure the communication system, the installation of the base station is an obstacle. Therefore, it would be advantageous if a time division scheme could be incorporated into the spread spectrum scheme without installing a dedicated base station. The present invention has been made in view of such a background, and it is an object of the present invention to provide a spread-spectrum wireless communication apparatus that adopts a time-division method as a spread-spectrum method and that enables multiplex communication without installing a dedicated base station. With the goal.

[0004]

According to the present invention, there is provided a radio communication system using a spread spectrum modulation system which is generated from a plurality of other stations based on a time division format in which one frame period is divided into a predetermined number of time slots. Receiving means for receiving a signal and demodulating data; a time slot discriminating section for discriminating a current use state of a time slot based on a demodulated output received by the receiving means; A time slot determining unit for determining a time slot to be used for a response transmission by a communication partner station to be a receiving station while determining transmission of a call to a required time slot when the station is a calling station; The data related to the position of the time slot determined by the time slot determination unit, and used by the first calling station among the communicating stations. Time slot and a memory unit for storing data relating to serial numbers assigned time slot number or identification code as the first time slot, when the time slot of the own station as stored in the memory unit that,
A transmission unit for transmitting required data by a radio communication signal according to a spread spectrum modulation method, and a control unit for controlling the time slot determination unit, the time slot determination unit and the transmission unit based on a reception demodulation output from the reception unit. An object of the present invention is to provide a spread spectrum wireless communication device provided.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION All spread spectrum radio communication apparatuses (radio stations) are set to a reception state and monitor a communication state. When a spread-spectrum wireless communication apparatus of a certain wireless station starts communication with another station, a station (calling station) that starts transmission first checks the use state of a time slot related to time division (time slot determination unit). ). If it is determined in this confirmation that another station is not communicating, the calling station will
While allocating the own station to the first position time slot of the time division format in which the frame period includes a predetermined number of time slots, the communication partner station specifies the time slot position to be used for response transmission (for example, the time position of the fourth position). Slot), and transmission of required data is started. The calling station that transmits using the time slot at the first position is a pseudo base station, and the first time slot is a timing reference in time division when communication is performed between other wireless stations.

The called communication partner station (called station) determines the time slot position of the own station based on the data related to the time slot assigned to the own station included in the transmission data. Send a response. When another station starts transmission during the above communication, the own station (calling station) is allocated to the time slot at the second position, and the time slot position for response transmission of the communication partner station (receiving station) is designated. (For example, the fifth time slot). Further, when another station starts communication, the calling station allocates to the third time slot and the called station allocates to the sixth time slot. When the communication using the time slot at the first position ends, the station using the time slot at the second position becomes the pseudo base station, and when the communication at this station also ends, the station using the time slot at the third position becomes the pseudo base station. Become a base station. The pseudo base station always includes data relating to the pseudo base station declaration flag in the transmission data.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A spread spectrum wireless communication apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a main block diagram showing an embodiment of a spread spectrum wireless communication apparatus according to the present invention, FIG. 2 is an operation flowchart for explaining FIG. 1, FIG. 3 is a view showing an example of a time division format, and FIG. It is a figure showing the example of a format. Before explaining the operation of FIG. 1, the time division format in the present invention is shown in FIG.
This will be described based on (a). FIG. 3A shows an example in which one frame period is divided into six time slots No1 to No6.
Each time slot has a period of 10 ms. Therefore, one frame period is 60 ms. In addition,
The number of time slots in one frame period and the period of each time slot are arbitrary.

In the communication according to the present invention, a plurality of sets of one-to-one communication are performed based on a predetermined time division format. In the case of FIG. 3A, three sets of independent communication are possible. Become. The communication itself is performed by a spread spectrum modulation method. In this case, since it is time-division communication, all stations can use the same radio frequency and the same spreading code. This allows all wireless stations to monitor the communication status of other stations. Further, the station (calling station) that starts transmission uses (assigns) the No. 1 time slot at the first position with the highest priority, and uses the No. 2 time slot at the next position when this is used. In this case, if this is also used, the No. 3 time slot is used. That is, the No. 1 time slot is set as the highest use order, and hereinafter, the No. 2 and No. 3 time slots are used in order.

FIG. 1 will be described on the premise of the above. In addition,
The ST numbers in parentheses in the following description indicate each step in FIG. Each wireless station including the spread spectrum wireless communication device (hereinafter, abbreviated as “communication device”) having the configuration shown in FIG. 1 sets the device to a reception state (ST1). Therefore, the control unit
Under the control of 10, a switching circuit SW1 for switching between transmission and reception is set on the receiving side (a side). Thereby, the switching circuit SW1
, A signal from the antenna 1 is input to the receiving unit 2, where the RF / IF unit 2a performs high-frequency amplification and frequency conversion, the spread demodulation unit 2b demodulates the spread spectrum modulated signal,
The required processing is performed by the information demodulation unit 2c for demodulating the information, and the data Do is demodulated. Each communication device in the receiving state identifies whether the demodulated output from the receiving unit 2 includes a local code indicating the calling of the local station (ST2). The above-described identification is performed by the own-station code identification unit 4. The case where the own station code is included will be described later, and here, it is assumed that the own station code is not included (ST2-N).

[0010] Here, when a communication device (referred to as communication device A) related to a certain wireless station starts transmission (calling) to a communication device (referred to as communication device a) related to another wireless station, the transmission is started. (Transmission command signal) via the control unit 10,
The transmission command is determined by the transmission command determining unit 5 (ST3-Y). When this determination is made, the time slot determining section 6 determines the current use state of the time slot based on the demodulated output from the receiving section 2 under the control of the control section 10 (ST4). The demodulated output from the receiving unit 2 is not particularly provided as a demodulated output when no communication device is performing communication (this is referred to as no signal), and when communication is performed between other communication devices. The corresponding data is demodulated. Although an example of the signal format will be described later, the data includes data relating to the position of the time slot used and the identification symbol (number or the like) in addition to the original information data. When the No. 1 time slot is used, data relating to a pseudo base station declaration flag indicating a declaration as a pseudo base station is always included in the data.

From the above, if the demodulated output is a no signal, the time slot discriminating section 6 can discriminate that no time slot is used, and can discriminate the time slot even if it is used. Here, it is assumed that it is determined that no time slot is used. Based on this determination, the time slot determination unit 7 determines the time slot to be used for transmission (calling) as the No. 1 time slot under the control of the control unit 10 (ST1).
5). Along with this determination, the time slot used by the communication device a (calling station) as a communication partner station for a response is also determined by the time slot determination unit 7 (ST6). In this embodiment, the time slot for this response is a No. 4 time slot. Data indicating the determined response time slot is included in the transmission data. Further, the data relating to the position of the time slot determined by the time slot determination unit 7 and the time slot used by the first calling station among the communicating stations are serially numbered as the first time slot. The data relating to the attached time slot number or identification code is stored in the memory unit 8.

Hereinafter, using the determined No. 1 time slot, the communication device A serving as the calling station starts transmission (ST1).
7) Perform communication with the communication device a (ST8). At the time of the transmission, the control unit 10 switches the switching circuit SW1 to the transmission side (b side). The transmitting unit 3 is configured by the illustrated functional blocks, and time division transmission is performed by the control unit 10 controlling the information modulating unit 3a. To the information modulator 3a, in addition to the input data and the like Di, required data Ds such as a pseudo base station declaration flag and data relating to the response time slot position and number (or identification symbol) of the partner station are input, and the No. 1 time slot Sometimes modulation processing is performed. For this time division, the information modulating unit 3a has a function of temporarily pooling data. The output of the information modulation section 3a is transmitted from the antenna 1 via a spread modulation section 3b for performing spread spectrum modulation, an output section 3c for performing frequency conversion and setting of transmission output, and a switching circuit SW1.

Next, a description will be given of the operation until the communication device a serving as a receiving station starts communication by replacing FIG. 1 with the communication device a. When the calling station calls the wireless station of the communication partner, the code (own station code) of the station (calling station) is included in the transmission data. Whether the own code is included in the demodulated output of the receiving unit 2 is monitored by the own code identification unit 4. Here, if the own station code is included (ST2-Y), under the control of the control unit 10, the time slot deciding unit 7 decides the designated own station code (ST2).
9). The determined time slot is the No. 4 time slot from the above example. Data relating to the determined time slot position and number (or identification symbol) is stored in the memory unit 8. Using the determined No. 4 time slot, the transmitting unit 3 starts transmitting a response (ST10), and thereafter performs communication with the calling station (ST11). As a result, one-to-one communication using the No. 1 time slot and the No. 4 time slot is performed between the communication device A and the communication device a. This communication state is shown in FIG.

When ending the communication, when terminating from the calling station, data relating to the communication end flag is transmitted to the terminating station and terminating (ST12). When terminating from the terminating station, receiving is performed. The calling station transmits a communication end request flag to the calling station, and the calling station that has received this transmits data related to the communication end flag to end the processing (ST13). Whether or not the communication has been completed is determined by the communication end determining unit 9, and when the communication has been completed (ST12).
-Y or ST13-Y), and set to the receiving state again under the control of the control unit 10 (ST1). Next, a case where a communication device (hereinafter referred to as communication device B and communication device b) related to another radio station performs communication while communication is being performed between the communication device A and the communication device a This will be described with reference to FIG.
Here, the calling station is called a communication device B, and the called station is called a communication device b.

In this case, the time slot discriminator 6 of the communication device B serving as the calling station determines that the No. 1 time slot and the No. 4 time slot are used. Based on this determination, the time slot used for calling is determined to be the No. 2 time slot at the second position of the use priority (time slot determination unit 7). The data relating to the determined time slot position and number (or identification symbol) is stored in the memory unit 8.
To memorize. In addition, the response time slot of the called station is set to No.
5 time slots are determined (same determination unit 7). Since the determined time slot is other than the No. 1 time slot, the communication device B relating to the calling station does not become a pseudo base station, and therefore does not transmit data relating to the pseudo base station declaration flag. On the other hand, the communication device b serving as the receiving station is also determined to be No. 5 time slot based on the transmission data.
This No5 time slot is stored. As a result, between the communication device B and the communication device b, the No. 2 time slot and the No.
One-to-one communication using five time slots is performed.
This communication state is shown in FIG.

Next, while communication is being performed between the communication device A and the communication device a and between the communication device B and the communication device b, a communication device (another radio station) related to another wireless station. The case where the communication device C and the communication device c perform communication will be described with reference to FIG. Here, the calling station is called a communication device C, and the called station is called a communication device c. In this case, the time slot determination unit 6 of the communication device C serving as the calling station:
It is determined that the No1 time slot and the No4 time slot and the No2 time slot and the No5 time slot are used. Based on this determination, the time slot used for calling is determined to be the No. 3 time slot at the third position in the use priority order (time slot determination unit 7). Data relating to the determined time slot position and number (or identification symbol) is stored in the memory unit 8. Further, the response time slot of the called station is determined to be the No. 6 time slot (the determination unit 7). The determined time slot is No1
Similarly to the above, the communication device C relating to the calling station does not become a pseudo base station because it is other than a time slot, and therefore does not transmit data relating to the pseudo base station declaration flag.

On the other hand, the communication device c serving as the receiving station also determines the No. 6 time slot based on the transmission data, and stores the No. 6 time slot. As a result,
One-to-one communication using the No. 3 time slot and the No. 6 time slot is performed between the communication device C and the communication device c. This communication state is shown in FIG. As mentioned above,
When one frame is composed of six time slots No. 1 to No. 6 (FIG. 3A), three sets of one-to-one communication are possible.

Next, the case where the communication using the No. 1 time slot and the No. 4 time slot is completed in the communication state of FIG. In FIG. 2, in the case of the calling station, the determination of the current use state of the time slot by the time slot determination unit 6 is continued unless the determination of the communication end is performed by the communication end determination unit 9 (ST12-N). Is being done. Here, it is determined that the communication using the No. 1 time slot and the No. 4 time slot has been completed. That is, it is determined that the No. 1 time slot and the No. 4 time slot are free (ST4). In this case, the second
The communication device B relating to the calling station using the No. 2 time slot of the order changes the time slot number (or identification code) to the No. 1 time slot while keeping the time slot position of the currently used time slot. (ST5), the data relating to the pseudo base station declaration flag is transmitted. In addition, in response to this change, the response time slot of the communication device b relating to the receiving station is determined to be the No. 4 time slot (ST6), and transmitted to that effect.

The communication device b relating to the receiving station changes the time slot to the No. 4 time slot and continues the communication. When this time slot is changed, both the calling station and the called station rewrite the memory data in any one of the memory units 8. As a result of vacancies in the No. 2 time slot and the No. 5 time slot due to the above change, the time slots of the communication device C relating to the calling station and the communication device c relating to the receiving station using the third-rank time slot No. 3 are described. Is similarly changed to the No. 2 time slot and the No. 5 time slot, and the memory data is rewritten. The communication state after this change is shown in FIG. In this way, the calling station other than the pseudo base station always monitors the use state of the time slot, and if a vacancy occurs before the time slot used by the calling station, the time slot used including the called station is used. Move up the number (or identification symbol). Then, the calling station that uses the No1 time slot transmits data relating to the pseudo base station declaration flag. The pseudo base station declaration flag allows each communication device (radio station) to know the standard of the time slot, and it is not necessary to provide a dedicated base station for managing the time slot.

Next, an example of a signal format in the above-described communication will be described. FIGS. 4A and 4B show examples of the signal format. In FIG. 3A, P is a preamble, SW is a synchronization word, CAC is a control signal, TC
H is information data (video, audio, etc.), and G is a guard bit. In the above, the preamble is for the stabilization period of the RF signal, and during transmission, the signal of the antenna output is stabilized during this period, and during reception, P is set within this period.
LL is locked, and the clock for data reproduction is stabilized. The synchronization word is a signal for synchronizing with a TDM (time division) frame. When the receiving side can detect the synchronization word, it can be confirmed that the signal is a regular signal and synchronizes with a time slot. be able to. The guard bit is for preventing overlapping with the next slot signal, and prevents the next slot from being affected by propagation delay or the like.

FIG. 2B is a detailed configuration example of the CAC shown in FIG. 1A, where MS is a pseudo base station declaration flag, CS
Is a call flag, RS is a response flag, TS is time slot data (flag, position, number, etc.), RE is a communication end request flag, E is a communication end flag, MID is a local station call code, and UID is a partner station call. Code. FIG. 3C shows the configuration of FIG. 3B at the time of calling (pseudo base station), at the time of response, at the time of communication (pseudo base station), at the time of communication (stations other than the pseudo base station), and at the end of communication. 5 is a format example corresponding to a time and a communication end request. In each data, "1" (high) indicates that the flag is set.

[0022]

As described above, according to the present invention, time-division multiplex communication can be performed without providing a dedicated base station for time slot management, which has been required conventionally. Thereby, the communication system can be simplified and a plurality of one-to-one communication can coexist. Further, since the spread spectrum modulation method is used as the modulation method at the time of communication, the influence of interference on the transmission line is small, and therefore, the occurrence of signal errors can be suppressed low, and high transmission quality can be realized. Also, for time division communication, a spread code used for the above spread spectrum modulation method can be shared, and the same radio frequency can be used, so that devices of each wireless station can be shared. Thus, it can be said that the present invention can contribute to simplification of a wireless communication system and high-quality data transmission.

[Brief description of the drawings]

FIG. 1 is a main block diagram showing an embodiment of a spread spectrum wireless communication apparatus according to the present invention.

FIG. 2 is an operation flowchart for explaining FIG. 1;

FIG. 3A is a diagram showing an example of a time division format;
(B) to (e) are diagrams illustrating examples of communication states based on (a).

FIGS. 4A and 4B are diagrams showing signal format examples, and FIGS. 4C and 4B are diagrams showing specific data examples of FIG.

[Explanation of symbols]

 Reference Signs List 1 antenna SW1 switching circuit 2 receiving unit 2a RF / IF unit 2b spread demodulation unit 2c information demodulation unit Do demodulation data 3 transmission unit 3a information modulation unit 3b spread modulation unit 3c output unit Di input data 4 own station code identification unit 5 transmission command Judgment unit 6 Time slot judgment unit 7 Time slot decision unit 8 Memory unit 9 Communication end judgment unit 10 Control unit

Claims (5)

[Claims] 1. A radio communication signal by a spread spectrum modulation system, which is issued from a plurality of other stations based on a time division format formed by dividing one frame period into a predetermined number of time slots, and demodulates data. Receiving means, a time slot discriminating section for discriminating a current use state of a time slot based on a received demodulated output by the receiving means, and based on discrimination by the time slot discriminating section,
A time slot deciding unit for deciding transmission of a call to a time slot at a required position when the own station is a calling station, and a time slot determining a time slot to be used by a communication partner station as a called station for response transmission; Data relating to the position of the time slot determined by the time slot determining unit, and serially numbering the time slot used by the first calling station among the communicating stations as the first time slot. A memory unit for storing data relating to the obtained time slot number or identification code, and a transmission unit for transmitting required data by a radio communication signal according to a spread spectrum modulation method at a time slot of the own station stored in the memory unit, A control unit that controls the time slot determination unit, the time slot determination unit, and the transmission unit based on a reception demodulation output from the reception unit Spread spectrum radio communication apparatus characterized in that it comprises a. 2. The method according to claim 1, wherein the determination of the time slot used by the own station for transmitting a call is performed by the time slot determination unit, and when no time slot of the one frame period is used, the one frame period is determined. A flag declaring the use of the first time slot and determining the use of the first time slot in the required data,
2. The spread spectrum apparatus according to claim 1, wherein when the first time slot or a plurality of time slots after the first time slot are used, the next vacant time slot is determined. Wireless communication device. 3. A transmission command discriminating section for discriminating whether a command signal to transmit from the own station has been input is provided at the base of the control section, and when the transmission command discriminating section discriminates a transmission command, 3. The spread spectrum wireless communication apparatus according to claim 1, wherein the determination by the time slot determination unit and the determination by the time slot determination unit are performed. 4. A self-station code identification unit for identifying whether there is a self-station code for calling a self-station based on a reception demodulation output from the reception means, is provided at the control unit, and the self-station code identification unit is When the own station code is identified, the time slot determination unit determines a time slot to be used for response transmission based on the received demodulation output, and transmits a response by the transmission unit at the time slot according to the determination. 2. The spread spectrum wireless communication apparatus according to claim 1, wherein: 5. A communication end determining unit for determining whether communication with a partner station has ended is provided under the control unit. When the own station is a calling station, the communication end determining unit determines whether communication has ended. Until the time slot is determined, the current use state of the time slot is determined by the time slot determination unit. When the use of the time slot at the position before the own station is completed, the time slot number or identification code of the own station is changed. While the time slot number or identification code of the used time slot is advanced to the time slot number or identification code of the communication partner station and the time slot number or identification code for the response transmission is determined by the time slot determination unit so as to be advanced to the required number or identification code. , The time slot number or the identification symbol stored in the memory unit, 2. The spread spectrum wireless communication apparatus according to claim 1, wherein the information is updated to an identification symbol.