JP3535743B2 - Wireless communication network system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless communication network system for easily registering or deleting a terminal station as a mobile station in a base station.

[0002]

2. Description of the Related Art Wired networks using cables are
It is used as an established technology in various places in society. However, since it is wired, there is a problem that a large amount of cost is required for relocation and relocation. For such problems, making the cable wireless, that is, realizing a wireless LAN is an effective means. However, when constructing a wireless LAN, some problems occur because it is wireless.
Specifically, in order to allow the relocation or relocation of the terminal stations, a means to connect all the terminal stations to the base station regardless of where they move (or even when newly established) is required. And

[0003]

In the conventional wireless communication network system, the terminal station is registered in the base station while using the polling procedure. In this work, the operation of the communication system is temporarily stopped and the new terminal station is registered.

However, such updating work of the communication system is regarded as very problematic in operation, and becomes a factor that hinders efficient operation of the communication system.

Further, in a communication system composed of a plurality of base stations, the work of changing the registration destination base station of the terminal station is performed. For example, since the wireless communication environment changes significantly due to movement of equipment, change of direction, movement of people, etc.,
The registered base station must be modified to obtain a stable wireless communication state.

[0006] However, the conventional communication system cannot easily cope with the change of the communication situation and cannot construct an efficient communication system.

Further, in this type of wireless communication system, in order to guarantee the bit error rate similar to that of the wired system, it is necessary to use a very high technology and an expensive and large-sized device. Is. Also, when embedding data in the received frame, if the data length is not set correctly,
Since a short data frame is judged to be a long data frame, or a long data frame is judged to be a short data frame, it is dangerous to judge the data length while receiving. Will have a great impact on.

Therefore, in the conventional wireless communication network system, the data length is often fixed in order to realize an inexpensive and small communication device.

However, it is rare that the optimum data length for each application is unique to that system, and conventionally, the fixed data length suitable for the application is selected in consideration of the efficiency of the entire communication system.

Therefore, an object of the present invention is to easily realize registration and deletion of a terminal station in a base station by using a polling procedure, and to dynamically change data while maintaining a fixed wireless data frame length. An object is to provide a wireless communication network system capable of changing the frame length.

[0011]

According to a first aspect of the present invention, there is provided a base station having a wireless communication device and an information table,
A wireless communication network including a plurality of terminal stations having a wireless communication device and performing wireless communication with the base station, and sequentially performing data access by a polling method to terminal stations corresponding to information data registered in the information table. In the system, the base station provides data length instructing means for instructing a data transfer direction and a data length at the time of data exchange between the base station and the terminal station, and withdrawal request data transmitted from the terminal station. And an information data deleting unit that deletes the information data corresponding to the terminal station that has transmitted the leave request data from the information table when the information is received.

The invention according to claim 2 is provided with a base station having a wireless communication device and an information table, and a plurality of terminal stations having a wireless communication device for performing wireless communication with the base station. In a wireless communication network system for sequentially performing data access to a terminal station corresponding to registered information data by a polling method, the base station has a data transfer direction at the time of data exchange between the base station and the terminal station. And a data length instructing means for instructing the data length, and the join request data from the terminal station transmitted in response to a signal indicating that reception of the join request data from the base station is received, and this join request is received. And an information data registration means for registering information data relating to the terminal station that has transmitted the data in the information table.

According to a third aspect of the present invention, there is provided a base station having a wireless communication device and an information table, and a plurality of terminal stations having the wireless communication device for performing wireless communication with the base station, wherein the information table is provided. In a wireless communication network system for sequentially performing data access to a terminal station corresponding to registered information data by a polling method, the base station has a data transfer direction at the time of data exchange between the base station and the terminal station. And data length instructing means for instructing data length, and information data for deleting from the information table the information data corresponding to the terminal station that has transmitted the leave request data when the leave request data transmitted from the terminal station is received. Deletion means and a subscription request from the terminal station transmitted in response to a signal indicating that reception of subscription request data from the base station is permitted. Receiving data, it is characterized in that and a information data registration means for information data registered in the information table concerning the transmitted terminal station upon the subscription request data.

The invention according to claim 4 is provided with a base station having a wireless communication device and an information table, and a plurality of terminal stations having a wireless communication device for performing wireless communication with the base station. In a wireless communication network system for sequentially performing data access to a terminal station corresponding to registered information data by a polling method, the base station has a data transfer direction at the time of data exchange between the base station and the terminal station. And a data length instructing means for instructing a data length, and an information data deleting means for transmitting a departure confirmation inquiry and deleting the information data of the corresponding terminal station from the information table, wherein the terminal station is connected to the base station. It is characterized in that it is provided with a releasing means for releasing the connection.

[0015]

[0016]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a construction example of a wireless LAN based on a spread spectrum (SS) wireless communication system, which is two base stations 2-1 and 2-2 and terminal stations 3-1, 3-2 and 3-3. … 3-
i and. The base station 2-1 and the terminal stations 3-1, 3-2, 3-3 in the communication area of the base station 2-1 are SS
Data is transmitted and received by the communication method. Base station 2-2
And terminal stations 3-3 ... 3 within the communication area of the base station 2-2.
-Data is exchanged with i through SS communication. In other words, these base stations form a wireless LAN with each terminal station within its communication area, and access the terminal stations by a polling procedure to exchange data. Therefore, it is necessary that the terminal station that constitutes the wireless LAN of a certain base station is registered in the base station. In addition, the base station 2-1 and the base station 2-2
Connects to the wired LAN 1 and functions as a terminal of the wired LAN 1.

FIG. 2 is a block diagram showing a configuration example of the SS communication device in the base station, and FIG. 3 is a block diagram showing a configuration example of the SS communication device in the terminal station.

In FIG. 2, the SS communication device 2 on the base station side
Is composed of a wired communication unit 21, an SS wireless communication unit 22, a memory unit 23, and a control unit 24.

The wired communication section 21 is a section for communicating with the wired LAN 1, and is represented by, for example, an Ethernet or the like. The SS wireless communication unit 22 is a unit that controls SS modulation / demodulation, and the memory unit 23 includes the wired communication unit 21 and S
The S section is a section for storing and relaying data with the wireless communication section 22, and the control section 24 is a section for controlling these three blocks and relaying the data according to a predetermined procedure (protocol).

In FIG. 3, the terminal station 3 wirelessly transmits / receives data to / from the SS communication device 2 on the base station side, and is composed of an SS communication device 4 and a terminal device 5 connected to the SS communication device 4. The communication device 4 includes a terminal I / F unit 41, an SS wireless communication unit 42, a memory unit 43, and a control unit 44. The terminal I / F unit 41 is a unit that connects to the terminal device 5 and exchanges data, and a data exchange system such as a serial interface or a parallel interface is known. The SS wireless communication unit 42 is a unit that controls SS demodulation / modulation. As a matter of course, the SS modulation and SS demodulation methods of the wireless communication unit 22 of the base station 2 and the SS wireless communication unit 42 of the terminal station 3 must be the same. The memory unit 23 is a unit that stores and relays data between the terminal I / F unit 41 and the SS wireless communication unit 42, and the control unit 44 controls these three blocks and a predetermined procedure (protocol).
Is a part that relays data.

FIG. 4 is a block diagram showing details regarding SS wireless data communication common to both the base station 2 and the terminal station 3. In the figure, reference numeral 11 denotes a memory unit for recording communication data, which enables access from both the input / output of wireless data and the input / output of data with a host device. This memory unit 11 is one of the important points of system efficiency. For example, while sending wireless data,
If there is access from the host device, an efficient system cannot be constructed unless the host device permits access even during data transmission. Therefore, a memory having a plurality of input / output ports is adopted as the memory unit 11. In this embodiment, a memory having two ports on the host device side and the wireless side is adopted. 1
Reference numeral 2 is a serial / parallel conversion unit.
The parallel conversion unit 12 converts the parallel data from the memory unit 11 into serial data, sends this serial data to the SS wireless communication units 22 and 42, and converts the serial data from the SS wireless communication units 22 and 42 into parallel data. And the parallel data is sent to the memory unit 11. A serial data transmission / reception unit 13 transmits / receives digital data. The above corresponds to the memory units 23 and 43 of the base station 2 and the terminal station 3.

Reference numeral 14 denotes an interface section with the SS wireless communication section, which performs digital data modulation / demodulation in accordance with the adopted SS wireless modulation / demodulation. Reference numeral 15 denotes an SS wireless modulation / demodulation unit, which has a direct spreading method, a frequency hopping method, or the like.
The above is the SS wireless communication units 22 and 42 of the base station 2 and the terminal station 3.
Equivalent to. Reference numeral 16 denotes an interface unit with the terminal device or the base station side. In the case of a terminal device, for example, a serial system such as RS-232C as an external connection or a bus connection as an internal connection is adopted according to the connection system. On the base station side, the bus connection method is adopted because high-speed data communication is required. The above is base station 2
Of the wired communication unit 21 and the terminal I / F unit 41 of the terminal station 3. Reference numeral 17 denotes a CPU which controls this constituent block. The CPU 17 controls the base station 2 and the control unit 2 of the terminal station 3.
Equivalent to 4,44.

In this type of wireless communication system, the CSMA (Carrier Detection Multi Access) method used in a wired system cannot be a means for providing effective multi access. (1) Even when the receiving side can detect transmission from a terminal other than the target terminal, the transmitting side cannot detect transmission of other terminals. (2) When multiple wireless stations transmit simultaneously, the receiving station On the side, there are times when it can not receive at all, when it can receive a frame from the target terminal, and when it can receive a frame from the other terminal that is disturbing,
This is because there are perspective problems, hidden terminal problems, etc.

On the other hand, in the field of wireless communication, a polling method that does not fundamentally cause the above problems is often adopted. In this polling method, since communication is performed under the control of the base station, a situation in which a plurality of terminal stations transmit at the same time cannot occur.

This polling method is one of the well-known access methods in the wired network, and typically,
Whether the network management device sequentially calls the terminal device connected to the network at a fixed time interval to transfer data,
This is a method of knowing whether or not the device is busy and performing corresponding processing (data transmission / reception, etc.).

However, the management of the base station in the polling method means a terminal registered in the base station, and it is caused by the complicated movement of the base station due to movement peculiar to the radio equipment or deterioration of the radio condition. It has a disadvantage.

In this embodiment, a simple base station switching method is provided for this problem. In the following, join and leave are used as terms relating to this base station switching.
Joining means registering the terminal station in a polling table managed by the target base station, and leaving means deleting the terminal station from the table.

FIG. 5 shows the operating phases of the device shown in FIG. The P phase is a phase for performing a polling operation and a leaving operation, and the C phase is a phase for performing a joining operation. In the P phase, the polling method is adopted as the access method, and in the C phase, the contention method by CSMA is adopted.

FIG. 6 is a specific example of the polling procedure in the P phase, and FIGS. 7 and 8 are flowcharts thereof. Referring to FIG. 7, base station 2 starts the P phase using the advertisement frame (S1). When the transmission of the P-phase start frame is processed (S2), the polling table (information table) of the base station is referred to (S).
3). Various information is stored in this polling table as shown in FIG. When the connection of the terminal station is confirmed according to this polling table (S4),
An inquiry frame is transmitted to the connected terminal station (S5). It waits until a response frame is transmitted from the first terminal station (S6), and when a response frame is received (S7), proceeds to the next table (terminal station) (S6).
8) If the next terminal station exists, S3 to S8 are repeated. If the response frame is not received within the predetermined time in S6, reception error processing is performed (S9).

If the next table (terminal station) does not exist in S8, the process proceeds to S10 shown in FIG. 7 and the polling table (information table) of the base station is referred to. When there is communication data to be transmitted to the first terminal station (S11), first, the instruction frame is transmitted to that terminal station (S12). Then, an information frame is transmitted and received (S13), and then the process proceeds to the next table (terminal station) (S14). If the next terminal station exists, S10 to S10.
Repeat S14. If the next terminal station does not exist, the P phase ends.

Next, the operation of leaving the terminal station will be described with reference to FIG.

This withdrawal operation is executed in S5 to S7 in the P phase described above. In this embodiment, as shown in FIG.
-2 shall be left. First, as shown in FIG.
An inquiry frame is transmitted to the terminal station 3-1 whose connection has been confirmed (S5), waits until a response frame is transmitted from this terminal station 3-1 (S6), and when a response frame is received, (S7), proceed to the next terminal station 3-2 (S
8). If the next terminal station 3-2 exists, the inquiry frame is transmitted to the terminal station 3-2 whose connection has been confirmed (S5).

If the terminal station 3-2 is to be departed, a "leave request" is included in the response frame from the terminal station 3-2.
Is waited for (S6), and the response frame is received by the base station (S7). Although not shown in FIG. 10, the process proceeds to the next terminal station 3-3 (S8), and if the next terminal station 3-3 exists, S3 to S8 are repeated.

Thus, the departure from the base station can be realized in the P phase. In other words, the terminal station makes an "inquiry response" to the "inquiry" from the base station, but by embedding the departure request information in this "inquiry response", the terminal station detects the departure request of the terminal station. be able to. The base station that has detected this departure request confirms the departure request and confirms an affirmative response as shown in the latter part of FIG. Delete from the station polling table (information table).

By using the above leaving operation method, the leaving operation of the terminal station can be easily executed while adopting the polling method.

As another example, the terminal station-led operation of leaving a terminal station may be executed. For example, when a base station stops its operation, if the terminal station to which it belongs can be detached by an instruction from the base station, the terminal station tries to connect with another base station without sudden interruption of communication. be able to.

Explaining the leaving operation in this case, when the base station wants to leave the terminal station for some reason, for example, the base station "inquires" to the target terminal station by the procedure shown in the latter part of FIG. "Leave confirmation" in the frame
The terminal station receiving the "query" frame in which the "leave confirmation" is embedded transmits a response frame in which the "leave confirmation" is embedded as the response. By confirming this departure, the base station can delete the terminal station from the polling table.

By using such a method, it is possible to confirm the time points at which the communication connection between the base station and the terminal station is cut off, so that the base station and the terminal station do not suddenly become incommunicable. It is possible to smoothly shift to the next processing.

In the above P phase, in short, the terminal station status registered to the polling table of the base station is queried for the following purposes. (1) Confirm the existence of the terminal station and confirm the possibility of communication. (2) Confirm the existence of data to be transmitted. This data includes D
own-Link (base station → terminal station) and Up-Link
There are both (terminal station → base station). (3) Confirm a normal response or an abnormal response to the transmitted data (Down-Link or Up-Link). (4) Confirm the request for leaving the terminal station (request for deleting from the polling table).

When there is data to be communicated, the data is individually exchanged with the terminal station for the following purposes. (1) "Data exchange" between the base station and the terminal station. Down-Link and Up-Link
There are two ways. (2) Check the length of the data frame used for "data exchange".

Here, "data exchange" will be described.

As described above, the polling procedure is composed of the two operations of "query" and "data exchange". In the first "inquiry" period, the base station communicates "data" to each terminal station (this data is simply a collection of 1s and 0s in the polling function, and the content is a higher-level protocol or program). The communication information, the operation information between the base station and the terminal device, etc. are confirmed. This is done by "inquiry" and "inquiry response" control frames between the base station and each terminal station. The "data exchange" period is sequentially processed for each terminal station that needs data communication by the above "query" work. The direction and length of the data transfer at this time is indicated by the "instruction" frame. For example, in accordance with the "instruction" frame from the base station, (1) the base station transmits data having a length of "100 bytes". (2) Send data of length "128 bytes" from the terminal station. And so on.
Such an "instruction" frame is "data exchanged" by the base station.
Since the actual data is sent after the occasional instruction, the terminal station or base station to which this data is destined can know in advance that the "data" frame will be sent and its data length.

In this embodiment, since the actual data is transmitted after the base station has instructed the "instruction" frame indicating the direction and length of the data transfer at the "data exchange" time, each terminal station may send the data as needed. The data length can be changed dynamically.

Next, the joining operation of the terminal station will be described.

In this embodiment, the base station employs the C phase, which is another operation phase. This C
The phase is a phase for joining processing. The base station is operated while switching between the P phase and the C phase depending on the setting conditions. For this switching procedure, an optimum method is selected depending on the destination of the application case.

FIG. 11 is a specific example of the joining procedure in the C phase, and FIGS. 12 and 13 are flowcharts thereof. Referring to FIG. 12, base station 2 starts the C phase using the advertisement frame (S21). When the transmission of the C phase start frame is processed (S22), the base station initiative operation is started (S23). As shown in the latter part of FIG. 11, this base station initiative operation is an operation of confirming the terminal station desiring to join and registering the confirmation result in the polling table of the base station. When the base station initiative operation is started, the polling table of the base station is referred to (S24), and the joining instruction is confirmed (S25).
When the joining instruction is confirmed, the joining instruction frame is transmitted to the terminal station (S26). Then, it waits until a response frame is transmitted from the terminal station (S27), and when the response frame is received (S28), the process proceeds to the next table (terminal station) (S29), and the next terminal station exists. If so, S24 to S29 are repeated. In S27,
If the response frame is not received within the predetermined time, reception error processing is performed (S30).

In S30, if the next table (terminal station) does not exist or the time is out, S shown in FIG.
In step 31, the terminal station initiative operation is started.

This terminal station-initiated operation is an operation for collecting the request from the terminal stations desiring to join by the contention system, as shown in the front part of FIG. When this terminal station initiative operation is started, it is confirmed whether or not a subscription request is received from the terminal station (S32). When this subscription request is received, a subscription request response frame is transmitted to the terminal station (S33). Then, the polling table of the base station is updated (S34), and until the time is up (S35), S32 to S34 are repeated, and the C phase of the present embodiment ends.

The above procedure is a procedure when the terminal station wants to join the base station, and the terminal station transmits the joining request by the contention method in (1) C phase (terminal station initiative operation period), (2) It is configured by a process of receiving a join request response from the base station in the C phase (base station initiative operation period).

On the other hand, in the case of a device (terminal station) such as a home television, a video recorder, or an office printer, which is in a normal standby state and awaits an operation from the user, communication is performed. Since there is no information,
Usually, it is desirable that it is deleted from the polling table of the base station.

Therefore, when it becomes necessary to communicate with a device (terminal station) in the standby state, it is necessary to join the terminal station from the base station. In this case, the presence or absence of a terminal station under the control of the base station is already known on the side of the base station, and therefore the operation of urging the base station to join is executed. In this case, as described above, by using the C phase (base station initiative operation period), the joining instruction frame is used for a known terminal station that is not connected, and the base station side sends The joining process can be started. When this terminal station receives the C-phase join instruction frame, it joins the base station using the join response frame.

By using the above joining operation method, the P phase can be switched to the C phase, and the terminal station can be easily joined by this C phase. In this C phase, the terminal station that is the object of joining detects the C phase of the base station, and the joining process to the base station is performed by the procedure shown in FIG. According to the figure, in this C phase,
(1) Period for accepting subscription request from terminal station, (2)
It can be seen that there is a period during which the base station confirms the subscription to the terminal station. That is, in the C phase, (1) an operation of collecting the request from the terminal station desiring to join by the contention method (terminal station initiative operation), (2) confirmation of the request to the terminal station desiring to join (terminal station to be joined) , Is configured by the base station initiative operation of registering in the polling table. This switching is performed, for example, by (1) embedding the information (terminal station-initiated operation or base station-initiated operation) in the C phase start frame, and (2) a certain fixed time out of the entire C phase for each operation period. Can be realized by a method such as assigning to.

By using the above-described method, it is possible to join and leave terminal stations while adopting the polling method, and to dynamically change the data length for each terminal station as needed. There is an effect such as being able to

[0055]

According to the present invention, it is possible to easily join and leave a terminal station to and from a base station while following a polling procedure, and a frame length switching function ensures reliable data communication in a wireless LAN system. Thus, it is possible to provide a wireless communication network system exhibiting high performance by simple operation and optimum wireless frame length.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration example of a wireless LAN system.

FIG. 2 is a block diagram of a base station SS wireless communication device.

FIG. 3 is a block diagram of a terminal station SS wireless communication device.

FIG. 4 is a block diagram of a detailed SS wireless communication device.

FIG. 5 is a block diagram of an operation phase.

FIG. 6 is a diagram showing a communication procedure between a base station and a terminal station in the P phase.

FIG. 7 is a flowchart showing a communication procedure between a base station and a terminal station in the P phase.

FIG. 8 is a flowchart showing a communication procedure between a base station and a terminal station in the P phase.

FIG. 9 is a diagram showing a polling table.

FIG. 10 is a diagram showing a procedure of leaving in the P phase.

FIG. 11 is a diagram showing a procedure of joining in the C phase.

FIG. 12 is a flowchart showing a procedure of joining in the C phase.

FIG. 13 is a flowchart showing a procedure of joining in the C phase.

[Explanation of symbols]

2-1 and 2-2 base station 3-1, 3-2, 3-3 ... 3-i terminal station 21 Wired communication section 22 SS wireless communication unit 23 Memory section 24 Control unit 41 Terminal I / F part 42 SS wireless communication unit 43 memory 44 Control unit

─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A-8-213993 (JP, A) JP-A-1-119147 (JP, A) JP-A-7-115422 (JP, A) JP-A-60- 25347 (JP, A) JP 5-48610 (JP, A) JP 7-312602 (JP, A) JP 63-306734 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 12/28 H04L 12/44-12/46 H04B ⁷ /24-7/26 H04Q 7/00-7/04 H04L 1/00-1/20 H04J 4/00-15/00 H04L 5/00-5/12

Claims (4)

(57) [Claims] 1. A base station having a wireless communication device and an information table, and a plurality of terminal stations having a wireless communication device for performing wireless communication with the base station, the information data being registered in the information table. In a wireless communication network system that sequentially performs data access to a corresponding terminal station by a polling method, the base station is configured to transmit data between the base station and the terminal station.
Data that indicates the data transfer direction and data length during exchange.
Data length instructing means, and information data deleting means for deleting from the information table the information data corresponding to the terminal station that transmitted the leave request data when the leave request data transmitted from the terminal station is received. a wireless communication network system, characterized in that it comprises. 2. A base station having a wireless communication device and an information table, and a plurality of terminal stations having the wireless communication device for performing wireless communication with the base station, the information data being registered in the information table. In a wireless communication network system that sequentially performs data access to a corresponding terminal station by a polling method, the base station is configured to transmit data between the base station and the terminal station.
Data that indicates the data transfer direction and data length during exchange.
Data length instructing means and a terminal which has received the join request data from the terminal station and is transmitted in response to a signal indicating that reception of the join request data from the base station is received, and which has sent the join request data. a wireless communication network system characterized in that it comprises an information data registration means for registering in said information table information data relating to the stations. 3. A base station having a wireless communication device and an information table, and a plurality of terminal stations having the wireless communication device for performing wireless communication with the base station, the information data being registered in the information table. In a wireless communication network system that sequentially performs data access to a corresponding terminal station by a polling method, the base station is configured to transmit data between the base station and the terminal station.
Data that indicates the data transfer direction and data length during exchange.
Data length deleting means for deleting the information data corresponding to the terminal station that has transmitted the leave request data from the information table when the leave request data transmitted from the terminal station is received, The information table for receiving the joining request data from the terminal station, which is transmitted in response to the signal indicating that the joining request data from the base station is permitted to be received, and the information data relating to the terminal station that has transmitted the joining request data, is stored in the information table. a wireless communication network system characterized in that it comprises an information data registration means for registering the. 4. A base station having a wireless communication device and an information table, and a plurality of terminal stations having a wireless communication device for performing wireless communication with the base station, the information data being registered in the information table. In a wireless communication network system that sequentially performs data access to a corresponding terminal station by a polling method, the base station is configured to transmit data between the base station and the terminal station.
Data that indicates the data transfer direction and data length during exchange.
A data length instruction means, an information data deletion means for transmitting a departure confirmation inquiry and deleting the information data of the corresponding terminal station from the information table ,
For example, the terminal station, a wireless communication network system including, be characterized by a withdrawal means for releasing the connection with the base station.