KR20050088323A - Random access control method, base station, and terminal device - Google Patents

Abstract

A random access control method assumes a case that a plurality of terminal devices (1-1 to 1-N) and a base station (3) communicate with one another via a satellite (2) and the same spread code is assigned for each of the terminal devices. For example, the base station (3) notifies predetermined delay time information to each terminal device. Next, each of the terminal devices spreads its transmission data with the same spread code and further arranges the spread transmission data whose delay time has been adjusted according to the delay time information in a predetermined slot (slot length > transmission data length) so as to be transmitted. Lastly, the base station (3) despreads each of the reception signals and extracts data of each terminal device.

Description

Random access control method, base station and terminal device {RANDOM ACCESS CONTROL METHOD, BASE STATION, AND TERMINAL DEVICE}

The present invention relates to a random access control method using Code Division Multiple Access (CDMA), and more particularly, to a random access control method when a plurality of terminal devices are assumed to communicate with a base station using the same spreading code. .

Hereinafter, a random access control method in the conventional communication system will be described. For example, as a basic random access control method in which each terminal randomly transmits a packet without fixedly assigning a radio channel to each terminal (mobile station), a slot aloha (Slotted-ALOHA) method (see Non-Patent Document 1). There is this. In this slot Aloha system, the time axis is partitioned at regular time intervals called " slots, " and packets are transmitted using this slot. Since the time axis is slotted, it is necessary to establish synchronization in each terminal. In addition, the slot Aloha method does not partially overlap the packet, as in the most basic Pure-ALOHA method, and the packet is either completely overlapped (crashed) or not completely overlapped.

On the other hand, in a communication system in which many terminals communicate with the same base station, it is effective to use CDMA with excellent throughput performance in order to increase the number of terminals that can be accommodated.

In the following, the conventional random access control method in which CDMA having excellent throughput characteristics is applied to the slot Aloha method will be described briefly. For example, each terminal on the transmitting side spreads the transmission data by the individually assigned spreading code. The spread signal is transmitted in synchronization with the slot time by the slot aloha method. On the other hand, the base station on the receiving side despreads the signal transmitted by the slot Aloha method by the individual spreading codes and extracts a desired signal. As a result, a desired signal can be extracted even at the time of collision. In addition, since a signal can be extracted even at the time of a collision, retransmission of packets is reduced, resulting in an improvement in throughput characteristics.

[Non-Patent Document 1]

Journal of the Institute of Electronics and Information Sciences Theological Bulletin DSP99-65, SST99-21, CS99-67 (1999-07)

However, when the conventional random access control method in which CDMA is applied to the slot Aloha method is applied to a system in which a situation in which the same spreading code is allocated to a plurality of terminals is assumed, a desired signal can be extracted due to packet collision. There is nothing happening. In particular, in the case where the conventional random access control method is applied to a satellite communication system (system in which a plurality of terminals use the same spreading code is assumed) in which the distance from the satellites becomes substantially equal between terminals, slots There is a problem that the probability of matching the reception timings is very high (no chip misalignment), whereby the desired signal cannot be extracted.

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and even in a case where a situation in which the same spreading code is assigned to a plurality of terminals is assumed, a random access capable of extracting a desired signal with good precision and further improving throughput can be realized. It is an object to provide a control method.

Disclosure of the Invention

In the random access control method according to the present invention, a random access control method in which a single or a plurality of terminal apparatuses and a base station communicate via a satellite and the same spreading code is assigned to the respective terminal apparatuses, A base station generating delay time information for generating predetermined delay time information for each terminal device to individually adjust delay time of transmission data, and notifying the terminal device of the delay time information; A spreading step in which the device spreads each transmission data with the same spreading code, and further, a predetermined slot (slot) for the transmission data after the spreading in which each terminal apparatus individually adjusts the delay time based on the delay time information. A delay time adjustment step of transmitting the data in a length > And extracting data of each terminal device by separately despreading the received signal.

According to the present invention, the base station notifies each terminal via satellite of delay time information that describes, for example, a delay time in the chip unit of a spreading code, and each terminal transmits the transmission data based on the delay time information. , The chip unit is also randomly transferred within one slot including the guard time. This reduces the collision (disappearance) of the slot.

1 is a view showing the configuration of a communication system according to the present invention;

2 is a diagram illustrating delay time information of a first embodiment;

3 is a diagram illustrating an example in which each terminal transmits data while arbitrarily transferring transmission data within one slot;

4 is a diagram illustrating a configuration of a terminal and a base station;

5 is a diagram showing an example of processing in the random access control method according to the second embodiment;

6 is a diagram showing an example of processing in the random access control method according to the second embodiment;

7 is a diagram showing an example of processing in the random access control method according to the second embodiment;

8 is a diagram showing an example of processing in the random access control method according to the second embodiment;

9 is a diagram showing delay time information according to the third embodiment;

10 is a diagram showing an example of processing in the random access control method according to the fourth embodiment;

11 is a diagram showing a random access control method according to the fifth embodiment;

12 is a view showing an example of a slot format of Embodiment 5;

13 is a view showing an example of a slot format of Embodiment 6 in each terminal;

14 is a diagram showing a reserved type random access control method according to the seventh embodiment.

Best Mode for Carrying Out the Invention

EMBODIMENT OF THE INVENTION Below, embodiment of the random access control method, base station, and terminal apparatus which concerns on this invention is described in detail based on drawing. In addition, this invention is not limited by this Example.

(Example 1)

In this embodiment, as an example of a communication system, a random access control method in the case of using a quasi-ceiling satellite system will be described. It is assumed here that a quasi-ceiling satellite system employs a random access control method in which CDMA is applied to the slot Aloha method, and the same spreading code is assigned to a plurality of terminals.

This quasi-ceiling satellite system is an area-limited satellite system in which three satellites move around the earth in a day through a predetermined orbit, and at least one of the three satellites always exists near the sky (ceiling) of Japan. In addition, when the satellite is switched every 8 hours, an elevation angle of 60 ° or more is always secured, and the user is always in good communication with a mobile communication service (car phone service, cellular phone service, GPS) which is less likely to block communication lines by buildings and the like. Other simplified positioning systems, etc.). Specifically, since the satellite always exists within 20 ° from the ceiling when viewed in the major regions of Japan, for example, only by placing the antenna of the car toward the ceiling direction, even if the traveling direction of the car changes, it is always good communication. This makes it possible and also simplifies the communication device since satellite tracking becomes unnecessary.

1 is a diagram showing the configuration of a communication system according to the present invention, and includes, for example, a terminal 1-1, 1-2, ... 1-N, a satellite 2, and a base station 3. . In general, since a communication system via a satellite is almost equal in distance to each terminal between satellites, for example, when a plurality of terminals use the same spreading code, the reception timing of the slots may be identical at the base station. The probability of (collision) is very high (no chip misalignment), and if a collision occurs, the packet is invalid. Therefore, the communication system according to the present invention uses " send data + guard time " as one slot. For example, each terminal transmits data while arbitrarily transferring the transmission data within one slot. As a result, chip shift occurs and, for example, the base station can extract a desired received packet due to the characteristics of CDMA (which can reduce inter-code interference due to chip shift).

2 is a diagram showing delay time information of the first embodiment in which the base station 3 notifies each of the mobile stations 1-1 to 1-N. Specifically, (a) shows a slot format when the base station transmits delay time information by TDM (Time Division Multiple), and (b) indicates that the base station transmits delay time information by CDM (Code Division Multiple). Slot format in case of error. When transmitting delay time information by TDM, a specific time zone or all of the slots are allocated as the time zone for delay time information, and when the delay time information is transmitted by CDM, a specific channel (Ch in FIG. # 1) is allocated as a channel for delay time information. In addition, as shown in the figure, it is not necessary to be a CDM for the downlink (base station → each terminal). Each terminal determines the transmission position of the transmission data based on this delay time information.

3 is a diagram illustrating an example in which each terminal transmits data while arbitrarily transferring transmission data within one slot (T _slot ). In addition, the illustrated slot is composed of a plurality of symbols, and spreading / despreading processing is performed in units of symbols.

Here, the random access control method of the present embodiment will be described. 4 is a diagram showing the configuration of each of the terminals 1-1 to 1-N and the base station 3, where each terminal spreads the transmission data S ₁ (t) to S _N (t) with the same spreading code. 11-1, 11-2, ..., 11-N, delay control units 12-1, 12-2, ..., 12-N for adding a delay to the spread signal in a predetermined process described later, Signal extracting units 13-1, 13-2, ..., 13-N for extracting delay time information and data sent from the base station, and the base station 3 despreads the received signal to receive the received data Z ₁ ( Despreading units 31-1, 31-2, ..., 31-N for outputting t) to Z _N (t), delay time information generating unit 33 for generating delay time information described later, and delay It is set as the structure containing the signal generation part 32 which multiplexes time information and the data to each terminal, and outputs.

For example, in the base station 3, the delay time information generator 33 generates delay time information of each embodiment described later, and the signal generator 32 causes the delay time information and each terminal via the satellite 2 to be used. Multiplex the data of the furnace and send it. In the delay time information of this embodiment, the delay time in the chip unit of the spreading code is described. In each terminal, each signal extractor extracts the delay time information and data about itself.

Further, in each terminal, each spreading unit spreads each transmission data with the same spreading code, and each delay control section controls the transmission timing of the spreading transmission data in the slot based on the delay time information. At this time, the delay control section of each terminal randomly selects a delay time in units of chips from the delay time information, and arranges and transmits spread data after spread with the delay time in a predetermined slot (see Fig. 3).

In the base station 3, each despreader despreads the received signal and extracts original transmission data. At this time, since inter-code interference is reduced by the processing of the delay control unit of each terminal, the base station 3 can extract desired data by despreading for each symbol.

As described above, in the present embodiment, the base station notifies each terminal via the satellite of the delay time information describing the delay time in the chip unit of the spreading code, and each terminal transmits the transmission data based on the delay time information. It is assumed that the chip unit is also randomly transferred within one slot including the data. As a result, the collision (dissipation) of the slot can be reduced, and as a result, an improvement in throughput can be realized.

In addition, in this embodiment, each terminal randomly selects a delay time in units of chips, but the present invention is not limited thereto. For example, the base station can identify a delay time in units of chips of spread codes and identification information of terminals (terminals). It may be possible to notify each terminal of the delay time information associated with the information). That is, the base station may determine the delay time in units of chips in each terminal. Thereby, collision of a slot can be avoided (or reduced).

(Example 2)

Next, the random access control method of the second embodiment will be described. In addition, since the system structure of this embodiment and the structure of each apparatus which comprises this system are the same as that of FIG. 1 and FIG. 4 mentioned above, the same code | symbol is attached | subjected and the description is abbreviate | omitted. The transmission methods (TDM, CDM) of the delay time information are also the same as in FIG. 2 described above. Here, only the operation different from the first embodiment will be described.

Also in the present embodiment, the base station 3 transmits the delay time information to the mobile stations via the satellites 2 in the same process as in the first embodiment. However, the delay time information of this embodiment is a time window position (for example, T _W of FIG. 5 or T _W0 , T _W1 , T _W2 of FIG. 6) for adjusting the delay time, and data within the range of the time window. Identification information of a plurality or a single terminal that permits transmission is associated. That is, the base station 3 divides each terminal into time window units.

5 and 6 are diagrams showing an example of processing in the random access control method according to the second embodiment. In the present embodiment, the delay control unit of each terminal recognizes a group (T _W or T _W0 , T _W1 , T _W2 ) of the time window to which its own terminal belongs based on the delay time information, and determines a chip unit in a specified time window. Delay time is selected, and spread-spreaded transmission data to which the delay time is added is placed in the slot for transmission.

As described above, in the present embodiment, the base station notifies each terminal via satellite of delay time information in which each terminal is grouped by time window unit, and each terminal transmits the transmission data within a specified time window based on the delay time information. It was supposed to transmit while transferring in the chip unit. As a result, the collision (dissipation) of the slot can be reduced, and as a result, an improvement in throughput can be realized.

In addition, in the present embodiment, as shown in Fig. 7, the size of the time window may be variable (corresponding to T _W0 and T _W1 in Fig. 7) in accordance with the amount of traffic in the time window. 8, the number of time windows may be adjusted in accordance with the amount of traffic in the time window. As a result, the search range at the base station can be adjusted.

In addition, in this embodiment, each terminal may transmit the transmission data while also randomly shifting the chip unit within a specified time window based on the delay time information. As a result, the transmission timing by each terminal can be made uniform within the time window, and the collision of slots can be further reduced.

(Example 3)

Next, the random access control method of the third embodiment will be described. In addition, since the system structure of this embodiment and the structure of each apparatus which comprises this system are the same as that of FIG. 1 and FIG. 4 mentioned above, the same code | symbol is attached | subjected and the description is abbreviate | omitted. Here, only the operation different from the first or second embodiment will be described.

Also in the present embodiment, the base station 3 transmits the delay time information to the mobile stations via the satellites 2 in the same process as in the first embodiment. However, in the delay time information of this embodiment, restriction information (for example, a congestion situation based on the traffic volume) relating to data transmission is set for each time window.

9 is a diagram showing delay time information of the third embodiment in which the base station 3 notifies each of the mobile stations 1-1 to 1-N. Specifically, (a) shows a slot format when the base station transmits delay time information by TDM (Time Division Multiple), and (b) indicates that the base station transmits delay time information by CDM (Code Division Multiple). Slot format in case of error. When transmitting delay time information by TDM, a specific time zone or all of slots are allocated as the time zone for delay time information, and when the delay time information is transmitted by CDM, a specific channel (Ch in FIG. # 1) is allocated as a channel for delay time information. The delay time information is set for each time window (delay time information # 1 to #n) with restriction information (congestion situation based on traffic amount) related to data transmission. In addition, as shown in the figure, it is not necessary to be a CDM for the downlink (base station → each terminal).

Next, in this embodiment, the delay control section of each terminal randomly selects a time window for performing data transmission based on the delay time information, that is, according to the congestion situation of each time window (for example, in FIG. T _W0 , T _W1 , T _W2 ), and randomly selects a delay time in units of chips within the selected time window, and transmits after spreading the transmitted data to which the delay time is added in a slot.

As described above, in the present embodiment, the base station sets restriction information relating to data transmission for each time window as delay time information, notifies each terminal of the delay time information via satellite, and each terminal is based on the delay time information. It is assumed that a time window for performing data transmission is selected at random, and the transmission data is transmitted while randomly shifting the chip unit within the selected time window. As a result, the collision (dissipation) of the slot can be reduced, and as a result, an improvement in throughput can be realized.

In addition, the limitation information in the present embodiment is not limited to the above, but is limited information that reliably transmits data of high priority or urgent users (limiting the number of users in a specific time window, expanding the time window, and specifying a specific time window). It is also acceptable to set a selectable identification number).

(Example 4)

Next, the random access control method of the fourth embodiment will be described. In Embodiment 4, for example, in the random access control method of Embodiments 1 to 3, when transmission data of a specific terminal cannot be accommodated in a time window of the same code, the transmission data of the terminal is different from the spreading code. Spread by and transmit. As a result, the collision (dissipation) of the slot can be reduced, and as a result, an improvement in throughput can be realized.

In the case of spreading and transmitting with the other spreading codes, as shown in FIG. 10, a portion of the small correlation between spreading codes may be selected to arrange the time window. Thereby, the collision of a slot can also be reduced.

(Example 5)

Next, the random access control method of the fifth embodiment will be described. For example, in a satellite communication system, a plurality of terminals may simultaneously transmit data. In this case, since the transmitted signals collide on the channel, the base station cannot extract their data, but such collision can be sufficiently suppressed by the base station control (ICMA: Idle-signal). Casting Multiple Access). Specifically, the result detected by the base station is transmitted to each terminal as Empty / Full information through the down channel. Each terminal transmits data after confirming that the Empty / Full information is " Empty ".

Since ICMA can improve the throughput by the above-described processing, it is applied to, for example, a mobile communication system of TDMA (Time Division Multiple Access). However, when a plurality of terminals simultaneously confirm "Empty" and transmit data at the same time, data cannot be extracted from the base station side due to collision.

Therefore, in the present embodiment, a random access control method using Empty / Full information is applied to the CDMA quasi-ceiling satellite system shown in FIG. In this case, it is assumed that the same spreading code is assigned to a plurality of terminals as an example. However, when there are many terminals to access, different spreading codes may be used. When the same spread code is used, interference between codes can be reduced.

Here, the random access control method of the present embodiment will be described. 11 is a diagram illustrating a random access control method according to the fifth embodiment. In addition, since the system structure of this embodiment and the structure of each apparatus which comprises the said system are basically the same as that of FIG. 1 and FIG. 4 mentioned above, the same code | symbol is attached | subjected and the description is abbreviate | omitted. Here, only operations different from those of the second and third embodiments described above will be described.

For example, in the base station 3, the delay time information generation unit 33 corresponds to the delay time information of the second and third embodiments described above, and empty / full information (window-by-Il) corresponding to the window unit. Is not necessary in case of delay time information) and received / non-receive information (corresponding to R / N shown) in units of terminals, and the signal generation unit 32 The data to each terminal is multiplexed and transmitted. In each terminal, each signal extracting unit extracts the delay time information, the Empty / Full information (not required for the delay time information of the third embodiment), the received / non-received information, and data about itself. .

Fig. 12 is a diagram showing an example of the slot format of the fifth embodiment in which the base station 3 notifies each mobile station 1-1 to 1-N (when the delay time information of the second embodiment is applied). Specifically, (a) shows the slot format when the base station transmits the delay time information by TDM, and (b) shows the slot format when the base station transmits the delay time information by the CDM. In the case of the TDM, a specific time zone or all in one slot is allocated for delay time information, empty / full information in time window units, and identification information in terminal units. In the case of the CDM, a specific channel (Ch # 1 in Fig. 12) is allocated as a channel for delay time information, empty / full information in units of time windows, and identification information in units of terminals. At this time, the traffic amount is described as empty / full information in units of time windows, and each terminal determines "Empty" and "Full" by using a threshold value of a predetermined criterion (the delay time of the third embodiment). Since the information includes the traffic volume for each time window, "Empty" and "Full" are determined based on this delay time information). In addition, the identification information of the terminal unit has described identification information of the terminal which was normally received in the last reception process, and each terminal judges whether to transmit new data or retransmission data by this. In addition, as shown in the drawing, the CDM does not need to be the downlink (base station → terminal).

Next, in the signal extracting unit of each terminal, for example, when the delay time information of the second embodiment is applied as the delay time information, the base station 3 is grouped in units of time windows, so that the above-described time window is specified. Check Empty / Full information. As a result, for example, when the Empty / Full information is "Empty" or less, and the reception / non-reception information of one's own terminal is "reception (with identification information)" or the first data transmission. On the basis of the delay time information, each terminal controls the new transmission data within a time window designated in the same order as in the second embodiment (spreading process, delay time adjustment, etc.). Also, the Empty / Full information of the designated time window is checked, and the Empty / Full information is " Empty (less than the threshold). &Quot; In the case of "non-receipt (no identification information)", each terminal controls the retransmission data within the time window specified in the same procedure as in the second embodiment (spreading process, delay time adjustment, etc.) based on the delay time information. In addition, when the Empty / Full information of the designated time window is "Full" (threshold exceeded), the transmission wait state.

On the other hand, in each signal extracting section, for example, when the delay time information of the third embodiment is applied as the delay time information, the congestion situation (traffic amount) of each time window in the delay time information is checked and "Empty" A time window for performing data transmission is randomly selected within the time window judged as " value or less). For example, in the case where the reception / non-reception information of the own terminal is "reception (with identification information)" or the first data transmission, each terminal performs new transmission data based on the delay time information. Control in the selected time window in the same procedure as in step 3 (spreading process, delay time adjustment, etc.). In addition, when the reception / non-reception information of the own terminal is "non-reception (no identification information)" despite the previous data transmission, each terminal performs retransmission data based on the delay time information. Control in the selected time window in the same procedure as in step 3 (spreading process, delay time adjustment, etc.). In addition, when it determines with all the time windows "Full (threshold exceeding)" in the said confirmation process, it will be in a transmission wait state.

Next, in the base station 3, each despreader despreads the received signal and extracts original transmission data. At this time, since inter-code interference is reduced by the processing of the delay control unit of each terminal, the base station 3 can extract desired data by despreading for each symbol.

As such, in this embodiment, the base station also notifies each terminal of the amount of traffic in units of time window and the reception / non-receive information in units of terminals via satellite, and each terminal receives the amount of traffic in units of time window and units of unit of reception / time of units. Based on the non-receipt information, the time window for performing data transmission and the data type (new / retransmission) are determined, and the transmission data (new / retransmission) is determined based on the delay time information of Example 2 or 3 described above. In the range of the time window, the chip units were also transmitted randomly. As a result, the collision (dissipation) of the slot can be further reduced, resulting in an improvement in throughput.

In the present embodiment, the Empty / Full information is set to two values, but the present invention is not limited thereto. For example, the Empty / Full information may be set in three or five steps. For example, in the case of the third stage, the congestion degree of the time window is expressed as "Empty", "Congestion", and "Full". This makes it possible to select / specify a more appropriate time window.

(Example 6)

Next, the random access control method of the sixth embodiment will be described. In the random access control method of the fifth embodiment, transmission data is transmitted in one slot, but in this case, the required S / N may not be satisfied depending on the communication state. Therefore, in the random access control method of this embodiment, the terminal transmits a plurality of identical transmission data, and the base station synthesizes the received data to improve the quality.

Here, the random access control method of the present embodiment will be described in detail. In addition, since the system structure of this embodiment and the structure of each apparatus which comprises this system are the same as that of FIG. 1 and FIG. 4 mentioned above, the same code | symbol is attached | subjected and the description is abbreviate | omitted. Here, only the operation different from the above-described fifth embodiment will be described.

First, each terminal measures S / N using the known symbol transmitted from the base station 3, and determines the number of identical transmission data to be transmitted continuously based on the measurement result. Each terminal inserts control information including the number of the same transmission data continuously transmitted and information on the time window, and transmits the control information to the base station 3 by inserting it into the transmission slot. FIG. 13 is a diagram illustrating an example of a slot format of Embodiment 6 in each terminal. FIG.

In addition, the control information describes, for example, information for allocating the same transmission data (which may change the coding pattern of error correction) by one chip length or more in one time window. Or, the information which allocates the same transmission data (you may change the coding pattern of error correction) to several time windows is described. Or, when the transmission power is insufficient, the information for allocating the same transmission data (you may change the encoding pattern of error correction) to several slots is described. In addition, the transmission time interval when allocating the same transmission data to a plurality of slots is variable according to the transmission path situation.

As described above, in this embodiment, since each terminal transmits a plurality of pieces of the same data, the communication quality can be improved in any transmission path situation by the synthesis processing by the base station.

(Example 7)

Next, the random access control method of the seventh embodiment will be described. Conventionally, in the random access control method of the reservation type, a specific terminal performs reservation of a data slot using an access slot, and a base station transmits a transmission timing and spreading code necessary for data transmission to a terminal whose reservation is made by the access slot. Notify and permit data transmission. The only terminal allowed to transmit data transmits the spread transmission data using the data slots based on the informed information.

However, when a conventional reserved random access control method is applied to a satellite communication system, for example, a plurality of terminals may make a reservation at the same time. In this case, in the Aloha system, since the transmitted signals collide on the channel, the base station cannot extract their data, and thus the reservation cannot be completed.

Therefore, in the present embodiment, the reserved random access control method of the present embodiment is applied to the CDMA quasi-ceiling satellite system shown in FIG. Fig. 14 shows a reserved random access control method of the present embodiment. Here, a data slot is reserved using the random access control method of Examples 1-4. Specifically, the transmission data in each embodiment is replaced with information (reservation information) for reserving a data slot, and the reservation information is transmitted using an access slot (TA _slot ). Then, the terminal which is permitted to transmit data transmits the transmission data using the data slot (T _slot ) based on the transmission timing and spread code notified in the same manner as in the conventional case.

As described above, in this embodiment, each terminal transmits information (reservation information) for reserving a data slot by using any one of the above-described embodiments 1-4. As a result, the collision (dissipation) of the slot can be reduced, and as a result, an improvement in throughput can be realized.

In the present embodiment, similarly to the sixth embodiment described above, each terminal may transmit a plurality of identical reservation information (see FIG. 13). As a result, communication quality can be improved.

As described above, according to the present invention, the base station notifies each terminal via satellite of delay time information describing, for example, a delay time in units of chips of a spread code, and each terminal, for example, The delay time in units of chips is randomly selected from the delay time information, and transmission data after diffusion delayed by the delay time is arranged and transmitted in a prescribed slot. As a result, the collision (dissipation) of the slot can be reduced, and as a result, an improvement in throughput can be realized.

As described above, the random access control method according to the present invention is useful for a communication system employing CDMA, and is particularly suitable when a plurality of terminal devices assume communication with a base station using the same spreading code.

Claims (46)

In the random access control method in which a single or a plurality of terminal apparatuses and a base station perform communication via a satellite, and the same spreading code is assigned to the respective terminal apparatuses, A delay time information generating step of generating, by the base station, predetermined delay time information for each terminal device to individually adjust delay time of transmission data, and notifying the respective terminal devices of the delay time information; A spreading step in which each terminal device spreads each transmission data with the same spreading code; A delay time adjusting step in which each of said terminal apparatus arranges and transmits said spread data to which said delay time is individually adjusted based on said delay time information in a prescribed slot (slot length> transmission data length); A data extraction step of the base station extracting data of each terminal device by individually despreading the received signal Random access control method comprising a. The method of claim 1, In the delay time information generating step, delay time in units of chips of a spread code is set as the predetermined delay time information, In the delay time adjusting step, randomly selecting a delay time in units of chips from the delay time information, and placing the spreading data after the diffusion delayed by the delay time in the prescribed slot. Random access control method characterized in that. The method of claim 1, In the delay time information generating step, as the predetermined delay time information, a delay time of a chip unit of a spread code and identification information of each terminal device are set in association with each other. In the delay time adjustment step, placing the spreading transmission data delayed by the delay time specified by the delay time information in the prescribed slot. Random access control method characterized in that. The method of claim 1, In the delay time information generating step, identification information of each terminal device divided into groups by a time window is designated as the predetermined delay time information. In the delay time adjusting step, based on the delay time information, it recognizes the time window to which its own terminal belongs, selects a delay time in units of chips within a specified time window, and transmits the data after the spread by the delay time. Arranging in said prescribed slot Random access control method characterized in that. The method of claim 4, wherein And the size of each time window is changed according to the traffic volume. The method of claim 4, wherein And adjusting the number of time windows according to the traffic volume. The method of claim 4, wherein In the delay time adjusting step, the random access control method, characterized in that for selecting a delay time in a chip unit randomly in the range of the specified time window. The method of claim 1, In the delay time information generating step, limit information on data transmission is set in units of time windows as the predetermined delay time information, In the delay time adjusting step, the time window for performing data transmission is randomly selected based on the delay time information, randomly selects a delay time in units of chips within the range of the time window, and is delayed by the delay time. Placing subsequent transmission data into the slots specified above Random access control method characterized in that. The method of claim 8, And a congestion situation based on the traffic amount as the restriction information. The method of claim 9, And the number of users of a specific time window is limited as the restriction information so that data transmission of a user having a high priority or a high degree of urgency is surely performed. The method of claim 9, And the time window is enlarged so as to ensure data transmission of a user having high priority and urgency as the restriction information. The method of claim 9, And the identification number for selecting a specific time window in advance so as to ensure data transmission of a user having high priority and urgency as the restriction information. The method of claim 4, wherein And when the transmission data of the specific terminal device cannot be accommodated in the time window of the same spreading code, the transmission data of the terminal device is spread with another spreading code and transmitted. The method of claim 13, In the case of spreading and transmitting with another spreading code, a random access control method comprising selecting a portion having a small cross correlation between spreading codes and arranging a time window. In the random access control method in which a single or a plurality of terminal apparatuses and a base station perform communication via a satellite, and the same spreading code is assigned to the respective terminal apparatuses, Delay time information in which the base station sets identification information of each terminal apparatus divided into groups by time window, Empty / Full information in which empty / Full is set in time windows, and An information generation step of generating reception / non-receipt information in which the result (the presence or absence of identification information) of the previous reception processing is set for each terminal device, and notifying the respective terminal devices of the respective information; A determination step of determining, by the terminal device, a time window and a data type (new or retransmission) capable of accommodating transmission data based on the respective information; A spreading step in which each terminal apparatus spreads each transmission data (new or retransmission) with the same spreading code; Each terminal apparatus selects a delay time in units of chips within a specified time window based on the delay time information, and transmits the spread data after the spread by the delay time in a defined slot (slot length> transmission data length). Delay time adjusting step of batch and transmission; A data extraction step of the base station extracting data of each terminal device by individually despreading the received signal Random access control method comprising a. The method of claim 15, In the determination step, In the Empty / Full information, the time window designated as the delay time information is "Empty" or less, and the setting of one's own terminal device in the reception / non-reception information is "reception (with identification information). Or in the case of the first data transmission, make the data type new data, In the Empty / Full information, when the designated time window is "Empty" or less, and the setting of one's own terminal device in the received / non-received information is "non-received (no identification information)". , The data type is resent data, In the Empty / Full information, when the designated time window is "Full (threshold exceeded)", the transmission wait state Random access control method characterized in that. The method of claim 15, In the delay time adjusting step, the random access control method, characterized in that for selecting a delay time in a chip unit randomly in the range of the specified time window. In the random access control method in which a single or a plurality of terminal apparatuses and a base station perform communication via a satellite, and the same spreading code is assigned to the respective terminal apparatuses, Delay time information in which the base station sets the presence or absence (Empty / Full) in units of time window as the restriction information on data transmission, and the result (the presence or absence of identification information) of the previous reception processing in each of the terminal devices. An information generation step of generating set reception / non-reception information and notifying the respective terminal devices of the information; A determination step of determining, by the terminal device, a time window and a data type (new or retransmission) capable of accommodating transmission data based on the respective information; A spreading step in which each terminal apparatus spreads each transmission data (new or retransmission) with the same spreading code; The terminal apparatus randomly selects a time window for performing data transmission based on the delay time information, randomly selects a delay time in units of chips within the range of the time window, and transmits after the diffusion that is delayed by the delay time. A delay time adjusting step of placing and transmitting data in a prescribed slot (slot length> transmission data length); A data extraction step of the base station extracting data of each terminal device by individually despreading the received signal Random access control method comprising a. The method of claim 18, In the determination step, Checking the delay time information and randomly selecting a time window for performing data transmission within a time window determined as "Empty" or less; When the setting of the own terminal device in the reception / non-reception information is "reception (with identification information)" or the first data transmission, the data type is set as new data, If the setting of one's own terminal device in the received / non-received information is "non-received (no identification information)", the data type is set as retransmission data, In the confirmation process, when all time windows are determined to be "full" (threshold), the transmission wait state is set. Random access control method characterized in that. The method of claim 19, The presence or absence of a space in said time window unit is determined from the congestion situation based on the traffic volume. The method of claim 15, The signal to noise ratio (S / N) is measured using the signal transmitted from the base station, and the number of identical transmission data to be transmitted continuously is determined based on the measurement result. Inserting the included control information into the slot and notifying the base station; Random access control method characterized in that. The method of claim 18, The signal to noise ratio (S / N) is measured using the signal transmitted from the base station, and the number of identical transmission data to be transmitted continuously is determined based on the measurement result. Inserting the included control information into the slot and notifying the base station; Random access control method characterized in that. Assuming a communication system in which a single or a plurality of terminal apparatuses and a base station perform communication via satellite, each terminal apparatus makes a reservation for data transmission using the same spreading code, and only a terminal apparatus permitted to transmit data. In the random access control method of the reservation type which performs data transmission using the individual spreading code notified from the said base station, A delay time information generating step of generating, by the base station, predetermined delay time information for each terminal apparatus to individually adjust delay time of reservation information, and notifying the respective terminals of the delay time information; A spreading step in which each terminal device spreads each reservation information with the same spreading code; A delay time adjusting step in which each terminal apparatus arranges and transmits the reservation information after spreading, in which the delay time is individually adjusted based on the delay time information, in a prescribed slot (slot length> reservation information length); The base station extracts the reservation information of each terminal device by individually despreading the received signal, and notifies the individual spreading codes necessary for data transmission to all terminal devices for which reservation has been completed; Random access control method comprising a. The method of claim 23, In the delay time information generating step, delay time in units of chips of a spread code is set as the predetermined delay time information, In the delay time adjusting step, randomly selecting a delay time in units of chips from the delay time information, and arranging the reservation information after the spread delayed by the delay time in the prescribed slot. Random access control method characterized in that. The method of claim 23, In the delay time information generating step, as the predetermined delay time information, a delay time of a chip unit of a spread code and identification information of each terminal device are set in association with each other. In the delay time adjusting step, placing the reservation information after the spread delayed by the delay time specified by the delay time information in the prescribed slot. Random access control method characterized in that. The method of claim 23, In the delay time information generating step, identification information of each terminal device divided into groups by a time window is designated as the predetermined delay time information. In the delay time adjustment step, based on the delay time information, it recognizes the time window to which its own terminal belongs, selects the delay time in units of chips within a specified time window range, and reserves the information after the diffusion delayed by the delay time. Arranging in said prescribed slot Random access control method characterized in that. The method of claim 26, In the delay time adjusting step, the random access control method, characterized in that for selecting a delay time in a chip unit randomly in the range of the specified time window. The method of claim 23, In the delay time information generating step, limit information regarding reservation information is set in units of time windows as the predetermined delay time information. In the delay time adjusting step, a time window for transmitting reservation information is randomly selected based on the delay time information, randomly selects a delay time in units of chips within the time window range, and delays the delay time by the delay time. Arranging reservation information after spreading in said prescribed slot Random access control method characterized in that. The method of claim 28, And a congestion situation based on the traffic amount as the restriction information. The method of claim 26, And when reservation information of a specific terminal device cannot be accommodated in a time window of the same spreading code, spreading the reservation information of the terminal device to another spreading code and transmitting the same. The method of claim 30, In the case of spreading and transmitting with another spreading code, a random access control method comprising selecting a portion having a small cross correlation between spreading codes and arranging a time window. In a base station that communicates with a single or a plurality of terminal devices to which the same spreading code is assigned via a satellite, A delay time information generating means for generating delay time information for setting a delay time in a chip unit of a spread code and for notifying the respective terminal devices of the delay time information; Base station characterized in that. In a base station that communicates with a single or a plurality of terminal devices to which the same spreading code is assigned via a satellite, Providing delay time information generating means for generating delay time information set by associating a delay time in a chip unit of a spread code with identification information of each terminal device and informing the respective terminal devices of the delay time information. Base station characterized in that. In a base station that communicates with a single or a plurality of terminal devices to which the same spreading code is assigned via a satellite, Providing delay time information generating means for generating delay time information for setting identification information of the respective terminal devices divided into time window units, and notifying the respective terminal devices of the delay time information. Base station characterized in that. The method of claim 34, wherein And a base station configured to change the size of each time window according to the traffic volume. The method of claim 34, wherein And a base station configured to adjust the number of time windows according to the traffic volume. In a base station that communicates with a single or a plurality of terminal devices to which the same spreading code is assigned via a satellite, Providing delay time information generating means for generating delay time information in which the limit information on data transmission is set in units of time windows and notifying the respective terminal devices of the delay time information; Base station characterized in that. The method of claim 37, And a congestion situation based on the traffic amount as the restriction information. The method of claim 38, The base station, characterized in that the number of users of a specific time window is limited so as to ensure data transmission of a user having a high priority or an urgent degree as the restriction information. The method of claim 38, The base station, characterized in that the time window is enlarged so as to ensure data transmission of a user having high priority and urgency as the restriction information. The method of claim 38, The base station characterized in that an identification number for selecting a specific time window is specified in advance so as to ensure data transmission of a user having high priority and urgency as the restriction information. In a terminal apparatus when communicating with a base station via a satellite and having the same spreading code assigned to a plurality of terminal apparatuses including its own apparatus, Spreading means for spreading transmission data to the spreading code; Randomly selects a delay time in units of chips from "delay time information in which the delay time in chip units of spread codes is set", and transmits the spread data after the diffusion delayed by the delay time in a prescribed slot (slot length> transmission data length). Delay control means arranged in the transmission Terminal device comprising a. In a terminal apparatus when communicating with a base station via a satellite and having the same spreading code assigned to a plurality of terminal apparatuses including its own apparatus, Spreading means for spreading transmission data to the spreading code; The transmitted data after the spread delayed by the delay time specified by " delay time information in the chip unit of spread code and the identification information of each terminal device " is stored in a prescribed slot (slot length > transmission data length). Delay control means to arrange and transmit Terminal device comprising a. In a terminal apparatus when communicating with a base station via a satellite and having the same spreading code assigned to a plurality of terminal apparatuses including its own apparatus, Spreading means for spreading transmission data to the spreading code; Based on the " delay time information in which the identification information of each terminal apparatus divided into groups by time window is set, " recognizes a time window to which its own terminal belongs, and sets a delay time in chip units within a specified time window. Delay control means for selecting and transmitting the spread data transmitted after the delay time by placing it within a prescribed slot (slot length> transmission data length). Terminal device comprising a. The method of claim 44, In the delay control means, the terminal apparatus further comprises randomly selecting a delay time in units of chips within a specified time window. In a terminal apparatus when communicating with a base station via a satellite and having the same spreading code assigned to a plurality of terminal apparatuses including its own apparatus, Spreading means for spreading transmission data to the spreading code; Randomly selects a time window for performing data transmission based on "delay time information in which the restriction information on data transmission is set in time window units", randomly selects a delay time in chip units within the time window range, and Delay control means for distributing the transmitted data after the spread by a delay time in a prescribed slot (slot length> transmission data length) Terminal device comprising a.