Method of controlling wireless communication in wireless network containing plurality of communication cells

[Detailed Description of the Invention]

[0001]

[Industrial Application]

Generally, about a correspondence procedure, more particularly, this invention relates to a plan setting method in order to re-use frequency in a multi-cellular radio network.

[0002]

[Description of the Prior Art]

A user like the portable computer which equipped communication capability in the Local Area Network (LAN), In order to communicate with remote equipment, or in order to use shared resources, such as a file server and a print server, it accesses to LAN through physical connection. In the operation of stationary mode, all the users are static and each user accesses to a network via the fixed homing point. However, it is impossible to restrict so that it may access to a network via one of some the homing points which the user under migratory environment could change the physical place freely, and were added to LAN. The homing point in migratory environment is a fixed header station which communicates with a move user via a radio link. A radio frequency (RF) link, a microwave link, and an infrared (IR) link are included in the example of a radio link.

[0003]

A wireless-communications network with duplicate hippo Checkout area, i.e., cell, for which the frequency respectively same uplink and for down-links is used in each area is considered as the object of concern here. It calls it frequency re-use to use the same frequency in the duplicate communication cell. Frequency re-use has the advantage that a move user removes the necessity of changing frequency, when moving to other cells from one cell.

[0004]

However, if cells differ, in order to transmit and receive a message within the cell of the multi-Cellnet work of the type which uses the same communication frequency, the interference management between users is needed. This interference may originate in various reasons including the down-link transmission from a header station in case the uplink transmission from a move user which carries out the whereabouts to the duplication area between the adjoining cells, and duplication cell area contain one or more move users.

[0005]

The record which teaches various modes of mobile communications is included in the United States patent and paper which are shown below. Two United States patents shown below show a communications system with duplication hippo Checkout area.

[0006]

U.S. Pat. No. 4,597,105 entitled "the data communication system with duplicate receiver hippo Resorzone" permitted to Freeburg on June 24, 1986 -- and U.S. Pat. No. 4,881,271 entitled the "portable radio communications system" permitted to Yamauchi etc. on November 14, 1989. According to Yamauchi etc., the method of handing over a member station from one base station to other base stations is proposed by supervising the signal strength of a member station continuously by a base station.

[0007]

The following United States patent teaches various aspects of a wireless-communications network.

[0008]

It has set to United States patent No.4,792,946 entitled "the radio Local Area Network for local use" permitted on December 20, 1988, and is S.Mayo, The Local Area Network which includes in a loop the transceiver station by which in-series combination was carried out is described.

[0009]

It has set to United States patent No.4,777,633 entitled "the base station for radio digital telephone systems" permitted on October 11, 1988, and is Fletcher, The base station which communicates with a member station using a communications protocol with a slot is described.

[0010]

It has set to United States patent No.4,730,310 entitled the "ground communications system" permitted on March 8, 1988, and is Acampora, A spot beam, TDMA, and the communications system that uses frequency re-use are described for communication between a base station and a remote station.

[0011]

The permission was granted on May 12, 1987. "in United States patent No.4,655,519 entitled radio computer modem], Kirchner is indicating about the radio modem for the Deya transmission in a computer Local Area Network.

[0012]

It has set to United States patent No.4,639,914 entitled "the radio PBX/LAN system by the optimal combination" permitted on January 27, 1987, and is Winters, In order to carry out this [ of the user / rediscount ] from a channel dynamically to a channel, it is indicating about the wireless LAN system which uses adaptive signal processing.

[0013]

It has set to United States patent No.4,837,858 entitled "the relayed sound / data communication system" permitted on June 6, 1989, and is Ablay, It is indicating about the relayed sound / data member who applies in either [ one ] audio mode or three data modes.

[0014]

it resembles United States patent No.4,852,122 entitled "the modem which was suitable as an object for wireless-communications channels" permitted on July 25, 1989, it sets, and Nelson is indicating about the radio communications system and the modem which performs especially a Data Terminal Equipment and digital data communication.

[0015]

It has set to United States patent No.4,926,495 entitled the "computer use dispatch system" permitted on May 15, 1990, and is Comroe, It is indicating about the computer use dispatch system containing a master file node and a plurality of user nodes. A master file node is automatically sent to each dispatcher added to the subgroup which maintains the record about each member, and to which a member applies the broken record in it.

[0016]

In United States patent No.4,456,793 permitted on June 26, 1984, W.E.Baker has described the cordless telephones system with the infrared radio link between a transmission-and-reception machine and a transponder. Cable connection of the transponder is made at a subsystem controller, and cable connection of the subsystem controller is made at a system controller. A prime controller polls a cordless station for every 100-mm second, in order to detect the place of a cordless station and to identify "missing" cordless station.

[0017]

In United States patent No.4,807,222 permitted on February 21, 1989, N.Amitay has described LAN which communicates with the local bus interface unit (RBIU) to which the user was assigned using RF or an IR signal. CSMA/CD and a protocol like ALOHA with a slot are used for communication with RBIU, for example.

[0018]

In United States patent No.4,402,090 by which was permitted on August 30, 1983 and general transfer was carried out, F.Gfeller has described the infrared transmission system employed between a plurality of satellite stations and a plurality of terminal stations. That ceiling installation of the host computer is carried out also communicates with a terminal station through a certain cluster control device and a satellite station. The communication with a terminal station is not interrupted during movement of a terminal station.

[0019]

In IBM technical announcement news flash Vol.20 and the No. December, 1977 [ 7 or ] item, F.Closs has described the use of prospect transmission of an infrared signal and both diffusion transmission used for the wireless communications between the control device of a ceiling base, and a plurality of terminals.

[0020]

In IBM technical announcement news flash Vol.24 and the No. January, 1982 [ 7 or ] item, F.Gfeller has described the general control principle of the infrared wireless network where a plurality of ceiling installation transponders which combine a host/controller with a plurality of terminal stations were contained. Access to an uplink channel is controlled by carrier sense multiplex access / the collision detection (CSMA/CD) method.

[0021]

[Problem(s) to be Solved by the Invention]

In the wireless-communications network used for a wired network, the matter which is not taught by this prior art and the matter which the object of this invention provides are correspondence procedure theories which realize efficient scheduling and re-use of frequency.

[0022]

[Means for Solving the Problem]

By how at least two of them manage wireless communications in a wireless-communications network with a plurality of communication cells which overlap mutually, the above-mentioned problem and other problems are conquered, and the object of this invention is achieved. A wireless-communications network in this case is a wireless-communications network of a type with a plurality of header stations which perform one or more mobile communications units and 2-way wireless communications, and perform 2-way communication with a wired network similarly. A method of following this invention includes the 1st phase of receiving a message from a wired network with at least one header station. A message in this case is a message of a type which approves transmission by a wireless network to one or more header stations. The 2nd phase of a method answers a received message, is attained, and starts wireless communications with arbitrary move units which carry out the whereabouts into a communication cell used by at least one header station.

[0023]

One method of this invention circulates a token of a high priority among a plurality of header stations connected to a wired network like a token ring, for example, without being limited to this. When a token is received, wireless communications are made to perform to a received header station. A header station sends a token to other header stations, after ending communication. Other methods of this invention assign a header station to a separate group, and a member of each group has the separated communication cell. this method includes a stage shown below -- namely, (a) -- a stage of searching for graph structure in which which communication cell has the peak corresponding to a stage;(b) communication cell which determines whether to overlap with other communication cells, In order to carry out interconnection of these peaks as a function of whether a predetermined communication cell overlaps with other communication cells and to summarize; (c) peak in a plurality of groups, each group comprises a separated communication cell in a stage of performing graph coloring art, and this case. in order that group-ized information may carry out wireless communications, it is maintained by a network control unit which operation-izes all the header stations of each group in parallel, and a group is continuous -- and it is operation-ized repeatedly.

[0024]

[Example]

General move office communication environment is shown in Drawing 1. Henceforth, the user with the portable data processing device called a mobile communications unit or move unit 10, Without receiving restriction in access to token ring communication network 1 through a predetermined homing point, a limited number which is called a header station here of devices are provided, and it is attached to token ring network 1 on a specific point. Each header station 12 has processing and accumulation capability, in order to carry out an accumulation communication function. Each header station 12 has a mediation function between cable token ring LAN and move unit 10 collection. Move unit 1O performs 2-way communication with header station 12 using a wireless-communications link. In the radio hippo register field or communication cell 2 of a header station, move unit 10 transmits on the 1st frequency (f-up) by common uplink, and receives a message on the 2nd frequency (f-down) by the broadcast down-link channel from header station 12. Within each cell of a multi-cellular radio network, the same frequency (f-up) and (f-down) are re-used.

[0025]

The suitable token ring network for performing the meaning of this invention, "IBM token ring network: It is indicated in architecture reference"SC30-3374-02, the 3rd edition, and September ("IBM" is a registered trademark of International Business Machines Corp.), 1989. However, the meaning of this invention is not restricted only to this specific network composition or a common token ring work, and please understand that it can realize in the wired network of very many types.

[0026]

Each move unit (N) is matched with one unique header station (12) called an owner (N), and accesses a move unit via an owner in a cable token ring network. The header station (H) can own a plurality of move units 10 simultaneously. Riot squad's 10 group owned by the header station (H) is called a domain (H).

[0027]

A suitable method for managing the ownership of move unit 10, KadathurS. American patent application serial number No for which Natarajan (lawyer approval number Y0990-117) applied to the basis of the title of "the distributed control method for the data station transfer management in a cable-communications network" and by which general transfer was carried out. It is indicated by _____.

[0028]

The relation between an owner and a domain is logical and the group of move unit l0 in which the communication necessity is managed by H is specified to each header station (H). However, when carrying out the whereabouts to the area where one move unit l0 overlapped, the uplink transmission can be heard by more header stations including an owner at present and all the potential owners of the cell in which the move unit carries out the whereabouts than one. For example, in Drawing 1, the uplink transmission from B may interfere with transmission by A, C, D, and E. However, since it is impossible absolutely, B and F do not interfere and suit that B and F transmit to the same header station 12. For the same reason, B and G interfere and do not suit. Interference is not restricted only to uplink transmission. The move unit in the duplicate cell field, for example, B, can receive the broadcast signal from a plurality of header stations 12 (B is receivable from both H1 and H2). If the broadcast message from header station 12 with many one move unit 10 is received simultaneously, a collision will occur and a message will be received accidentally.

[0029]

Therefore, interference management is needed in the transmission and reception of a message in one cell of the multi-Cellnet work of the type which adopts the same communication frequency in a different cell. This interference originates in the down-link transmission from header station 12, when various causes including the uplink transmission from move unit 10 which carries out the whereabouts to the duplication field between neighboring cells 2, and the duplication cell field of a header station contain one or move unit 10 beyond it.

[0030]

Suppose Drawings 2 and 3 showing the block diagram of the example of header station 12 and move unit 10, respectively, and also that it is referred to in detail before examining the method of this invention. In the desirable example of this invention shown here, a wireless-communications channel is transmitted via an infrared (IR) data link. According to the optical apparatus which can be used now, the employment in within the limits from about 750 nanometers to about 1000 nanometers is easy.

[0031]

The block diagram by which header station 12 was simplified is shown in Drawing 2. Header station 12 passes connector 14 and is LAN. It connects with 1. Connector 14 is connected with network adaptor transceiver 22, and this transceiver is connected with internal bus 24. Header station 12 is provided with processing unit 26 connected with memory 28 in 2-way, and the program relation containing the packet of transmission of as opposed to [ Because ] move unit 10 in Ri 28 or receiving data and other data are memorized. Processing unit 26 communicates with modulator 30a and receiver 30b in IR modulator and a receiver, and also details similarly. IR modulator and a receiver have the input connected with the suitable infrared emission or receiving set like a laser diode, a light emitting diode, and a photodetection device, for example.

[0032]

In the example shown in a figure, the output of modulator 30a is connected with a transformer mitt diode (TD), and the input of 30b is combined with a receiver by the receiving photo-diode (RD).

[0033]

The block diagram of the example of move unit 10 is shown in Drawing 3. Move unit 10 offers processing unit 32 combined with operator input device 34 and operator display device 36. Operator input device 34 is a keyboard or a suitable data input means, and does not interfere. Similarly, operator display device 36 is a monotonous panel alphanumeric character display or a suitable display means, and does not interfere. Similarly, memory 38 is combined with processing unit 32, and this memory memorizes the program related data and other data like the information packet for receiving or, for example, transmitting to header station 12, and discernment of move unit 10. Similarly, modulator 40a and receiver 40b are also combined with processing unit 32. The data receiver which shows in Drawings 2 and 3 has a demodulator and a filter, and extracts from the optical signal which received the bit stream operated and modulated by the usual method. Similarly, by the usual method, the showing-in 2 and 3 abnormal-conditions machine operates, and modulates an optical output according to the transmitted bit stream. Although arbitrary data-communications speed is adopted and it does not interfere, a desirable data-communications speed is per second about 1 to 10 million bits (1-10 Mbits/sec).

[0034]

In the optical communications system concerning this invention, all the wireless communications are performed between header station 12 and move unit 10. Direct communication between move units 10 is not performed.

[0035]

Although the wireless network which used IR medium is described here, please understand that the method of this invention can be enforced also to the wireless network type [ other ] like a radio frequency (RF) and microwave media, for example.

[0036]

In Drawing 1, token ring network 1 comprises 1 set of addition header stations (H1, H2, ... Hn) with Drawing 5. One of the features of a token ring network is that network message transfer has various priority levels. In this invention, the message of a high priority called permission wireless transfer (PERMIT_WIRELESS_TRAN) circulates. If each header station 12 (Hk) receives a PERMIT_WIRELESS_TRAN message, received header station l2 will come out of the usual state (A) of operation, and will go into the privilege state (B) of operation.

[0037]

Usually, header station 12 is in a state (A), The task of covering network 1 (state C), receiving the data by which the address was carried out to the move unit in the task of transmitting the token of data and a low priority, and the domain of Hk (state D), and carrying out a buffer is carried out.

[0038]

When it is in an exclusive state (B) in one example, header station 12 is, As shown in Drawing 4, execution of a protocol is enabled, simultaneously the broadcast possibility of and move unit (E) uplink transmission which polling of is still attained and has data which it is going to transmit can be pulled out to a move unit in the domain.

[0039]

Within a cell, when radio operation is perfect, header station 12 releases a PERMIT_WIRELESS_TRAN token, namely, a token is passed by the next header station 12 of a token ring. In Drawing 5, header station 12 is a method unrelated to radio operation, and the state by which it is shown above a broken chain line shows that reception and/or transmission of data are possible in cable token ring network 1. As far as cable token ring network 1 is concerned, it is considered that head station 12 is another workstation 12 physically connected to LAN.

[0040]

The protocol shown in Drawing 4 polls each move unit 10 one by one for uplink transmission of header station 12, and is simultaneous, Or then, it is an example of the suitable protocol which broadcasts a message to a down-link to move unit 10 according to two or more access protocols under operation.

[0041]

Another, suitable method for polling move unit 10, Kadathur for which it applied to ____ and by which general transfer was carried out U.S. patent application No of the title "the method of polling a move user in two or more cellular radio network" according to S.Natarajan and its cooperator (lawyer approval number YO990-146). It is indicated by _____.

[0042]

After polling and broadcast operation are completed, header station 12 makes radio operation finish. A header station transmits the PERMIT_WIRELESS_TRAN message of a high priority to the next header station 12 of token ring network 1 next. The next header station 12 which received the high priority token goes into the exclusive mode of wireless communications, is the same method and communicates with move unit 10 of the Accident domain here.

[0043]

A token is received by header station H1 when a PERMIT_WIRELESS_TRAN token will circulate through the inside of network 1, if it explains in detail. H1 goes into the exclusive mode and polls each move unit 10 which constitutes the domain of H1 at the present time one by one. According to Drawing 1, the group of move unit 10 in the domain of H1 is set to (A, B, C), and move units 10 in the domain of H2 are (D, E), and set the group of move unit l0 in the domain of H3 to (F, G). When H1 owns a PERMIT_WIRELESS_TRAN token, B is followed after move unit A, then it follows C, and H1 polls. Polling specific move unit 10, for example, A, means sending a polling message to move unit A, and standing by the instant response from A by a down-link. If a response does not act as Irikita instancy, a polling message will be sent to B. However, when move unit A answers by transmission by uplink to the polling message by a down-link, before polling move unit B, it waits for H1 until uplink transmission is completed.

[0044]

Header station H1 passes a PERMIT_WIRELESS_TRAH token to the next node of token ring network 1, after completing polling of all the move units 10 in the domain. When the following node is another header station (H2), H2 polls move unit 10 in that domain (D, E) at this time. A token is passed by the next node of a ring after H2 ends polling of all the related move units 10. After a PERMIT_WIRELESS_TRAN token returns to header station H1, H1 goes also into states B and E of Drawing 5 once. When the node which receives a PERMIT_WIRELESS_TRAN token is not header station 12, the route of the token is carried out instancy in token ring network 1. Therefore, header stations 12 can be made scattered with network device 3 of other types, for example, the central controller shown in Drawing 1.

[0045]

If it summarizes, this 1st method of this invention will attain effective control of wireless communications by the operation of the exclusive token through which it circulates. It is restricted to one single radio cell by definition that-izing can be carried out [ Operation ] at a certain arbitrary times. Therefore, the problem of the uplink interference between move units and the down-link interference between header stations is removed.

[0046]

The 2nd method of this invention that attains efficient re-use of the frequency in the radio communications system which has a duplication cell is described. This 2nd method provides inconsistency-less transmission in the radio portion of a network system, and provides efficient re-use of the bandwidth in the cell from which the wireless network was separated further spatially.

[0047]

The procedure of the 2nd method of this invention is shown in the flow chart of Drawing 9, and it describes below. Step A In order to determine the cell of the network of the radio which can carry out wireless communications simultaneously, without interfering mutually, off-line Procedure PI is used based on the knowledge about the position of cell 2 of network 1. Step B Concentrated type controller 3 added to token ring network 1, and since table 4 of a data processing device is generally initialized, the result of PI is used. Table 4 is used for controller 3 and it asks for the schedule for gaining the simultaneous radio operation which does not have interference within the cell from which the network was separated from a table. Even if both cells are operation-ized simultaneously, when not overlapping in the state where interference is caused, it is considered that these two cells are what is separated. Step C Controller 3 operation-izes the header station relevant to the separated cell alternatively according to the schedule for which it asked.

[0048]

These steps (A-c) are described still in detail. Step A Suppose that the multi-cellular radio network shown in Drawing 6 for explanation is considered. A network comprises the group of seven cells (A, B, c, D, E, F, G), and move unit 10 of 11 from No. 1 to No. 11. A field interference graph, i.e., RIG, is defined in case of known about a cell and its duplication characteristic. RIG has a plurality of peaks and each peak corresponds to one cell of a multi-Cellnet work. It is considered that the two peaks of RIG are what was limited to when it limits to when the corresponding hippo register of a cell overlaps, namely, the simultaneous wireless communications within a cell interfere mutually, and is connected. RIG corresponding to the network of Drawing 6 is shown in Drawing 7. The seven peaks of this RIG correspond to seven cells (A-G) of Drawing 6.

[0049]

The object of Procedure PI is to collect the groups of the separated cell and to make it one collection. As for this, it is preferred to attain by solving a graph coloring problem using a near number of colors the optimal or the optimal.

[0050]

Much suitable graph coloring art is known. For example, communication of :(1) D.Brelaz"new method of painting on the peak of graph" ACM which shows the reference about this seed art below, 22 or 1979, and 251 -256-page;(2) F.T.Leighton "graph coloring algorithm for large-sized planning problem" domestic standard office Journal, 84 or 1979, 489 -506-page;, and (3) M.Chamz, A. Hertz and D.De Werra "some experiments by imitation annealing about graph coloring", an operations research Europe journal, 1987 [ 32 or ], 260 - 266 pages. All the graph coloring art in which an appropriate quantity of running time attains near coloring the optimal or the optimal is suitable for this invention.

[0051]

If a graph coloring problem considers it as :graph G= (V, E) which can generally be expressed as follows, and integer K, For example, the function color shown below: V-> (1, 2, ..., K) exists, or use the value of the smallest possible K for the optimal coloring of a;(V, W) epsilonE=>color(V)!=color(W) ? graph.

[0052]

The minimum coloring solution to the graph shown in Drawing 7 is as follows (red =1, blue =2, green =3, black =4). color(F) =color -- (D) = red colorcolor[ (B) =color/ (E) = blue ] (A) =color(C) = green color(G) = black -- the peak which can assign the same color corresponds to the cell of the network not overlapping. The group of the separation cell identified by solving a graph coloring problem is called Group1, Group2, ..., Groupk. A certain header station may be a member of only one group.

[0053]

In order to improve this art so that it may state below, dignity attachment relevant to the node of the graph shall be performed, and weight shall correspond to the traffic intensity of a message. Step B Prime controller 3 is initialized using the calculation result by the graph coloring algorithm called the same above-mentioned procedure 1. That is, prime controller 3 is memory Monkey to table 4 about the data structure expressing the group of a cell according to the determination by Procedure 1. Step C Prime controller 3 sends the high multicasting message of a priority called START_WIRELESS_OPER here to all the header stations 12 which are the members of group 1, after being initialized. In the related cell, each header station 12 belonging to group 1 will start radio transmission with move unit 10, and receiving operation, if a START_WIRELESS_OPER message is received. Radio operation includes two or more access uplink transmission from move unit 10, and the broadcast transmission by the down-link from header station 12 to move unit 10.

[0054]

:(a) thoroughness service (b) limited service or (c) gate restriction service which can finish down-link transmission using three use dependence judging standards which show header station 12 below. It stops at broadcast mode until all the frames to which the buffer of the data was carried out are transmitted including all the cases where header station 12 can reach from a wired network into the present broadcast cycle in thorough service. In limited service, header station 12 stops at broadcast mode until broadcast of the predetermined number of a frame is completed between the predetermined amounts of the maximum time. When the broadcast To be frame still remains, those frames stop at the state where the buffer was carried out to the following communication cycle. In gate restriction service, if the following point is removed, I will hear that it is the same as thorough service, namely, only the frame by which the buffer is carried out at the beginning of a broadcast stage is transmitted. If it puts in another way, in order to broadcast in the following communication cycle, the buffer of all the frames that arrive into the present broadcast stage will be carried out.

[0055]

Even if any of these three standards are adopted, simultaneously with completion, header station 12 sends the message of a high priority called COMPLETED_WIRELESS_OPER here to prime controller 3.

[0056]

After prime controller 3 receives a COMPLETED_WIRELESS_OPER message from all the header stations 12 belonging to group 1, Multicasting message START_WIRELESS_OPER of a high priority is sent to all the header stations 12 which are the members of group 2. Header station 12 belonging to group 2 answers reception of a message, and starts the parallel-inconsistency-less radio operation in each domain. The operation to group 1 advances as above-mentioned. After prime controller 3 receives COMPLETED_WIRELESS_OPER messages from all the header stations 12 belonging to group 2, wireless communications are carried out within the cell which group 3 constitutes. If that of all the cells which constitute group k sends those COMPLETED_WIRELESS_OPER messages to prime controller 3, the cycle of radio operation will be completed. At this time, with prime controller 3 in the cell of group 1 which the cell of group 2 follows, it is started and another cycle of wireless communications advances in this way. As shown in Drawing 8, prime controller 3 covers a group, and it circulates through it repetitively, and it operation-izes each header station continuously.

[0057]

This method of this invention provides re-use of efficient bandwidth in a network radio portion. The best situation is attained when N radio cells exist in a network, and all N cells carry out mutual separation completely. In such a situation, all N cells can always carry out radio operation by a method without inconsistency. In a general radio environment, it is predicted that a certain amount of duplication occurs between cells. For example, when each cell overlaps with other two cells, N header stations 12 can be divided into three separation groups, and their an average of N / three header stations are feasible in radio operation at all the arbitrary times. The data transmission speed of token ring network 1 is l6. It is Mbits/sec, The header station of 30 carries out the whereabouts and it is 1, respectively. Uplink bandwidth effective when uplink of Mbit/sec is shared and it is divided into three separation groups is 10. It is Mbits/sec.

[0058]

Please understand enough that the meaning of this invention is not what is restricted only to the graph coloring art for determining statically the degree of non-interfering of formation of a cell operation. Similarly, as already annotated, also in static schedule engineering, dignity attachment showing the traffic intensity of a message is employable.

[0059]

For example, the number of packets of transmission To be traffic can change with cells to the intensity of traffic, i.e., unit time, according to Every, such as the number of move units 10 in a cell, and character of the application which generates traffic. If this kind of information is known, dignity (lambdaN) can be related with node N of RIG of Drawing 7 so that traffic intensity may be reflected. Therefore, classification-ization of RIG is formulated as an accepted static plan problem shown below. as field interference graph G= (V. E.) -- every -- Groupi (1<i<K) is an independent set and the following objective function serves as the minimum -- as :k which should just determine the classification of the peak set to integer K and the family of a subset (Group1, Group2, ... , Groupk) sigma lambda (Groupi) i=1 Here; lambda(Groupi) =max {lambda N|NepsilonGroupi} The combination of the still more nearly static schedule engineering as an example is employable. For example, a static graph coloring procedure is used first. :A= 10 message /as which the following average value about communication traffic is determined to the RIG peak after obtaining experience by the network planned in this way -- a second B= 5 message /-- a second -- C= 10 message /-- a second -- D -- = -- ten -- a message -- /-- a second -- E -- = -- ten -- a message -- /-- a second -- F -- = -- two -- a message -- /-- a second -- and -- G -- = -- one -- a message -- /-- a second .

[0060]

Control device 3 revises a plan table so that the operation-ized group sequence which makes the minimum service sum total time of all the header stations measured by message unit time may be provided using the average value of message traffic. The following group is not started until all the header stations of a precedence group are completed. For example, the optimal group sequence is FG after B after AD at CE and the next, All the time required is 27 message time bases, and on the other hand, after AF, the un-optimal group sequence is G after BD at EC and the next, and, as for the completion time required, it turns out that it is a message time basis of a total of 31 whole.

[0061]

Similarly, this invention is not restricted only to the static plan method. For example, dynamic schedule engineering is also employable. In the interference graph shown in Drawing 7, peak A, D, and F forms the independent set which is not directly connected on the edge. Control device 3 enables the wireless-communications start of peak A, D, and F first. Other peaks are investigated in order to determine whether other peaks can make an operation possible as for control device 3, without interfering with transmission of D and F, if A assumes that it is what is completed first. If other peaks do not exist, operation-izing more must wait, otherwise, control device 3 will operation-ize other not consistent header stations instancy. After A is completed in the above-mentioned example, without being contradictory to D or F, operation-izing is impossible for other header stations. Next, when it assumes that it is what F ends, control device 3 enables the operation of B, B and F form the independent set, and the transmission is non-interfering. As already stated, all the cells of one group should be careful also of a plan setup being adjusted so that the radio operation of all the cells of the group may be completed before the cell in other groups is permitted radio operation implementation. However, amendment of a method is also included in the scope of this invention. For example, unless it is contradictory to all on-going radio operations by that in other cells, the traffic load depending on plan setting art can also be used for prime controller 3 so that the radio operation within a predetermined cell may be started. This kind of improvement uses together the mechanism for securing a fair standard so that each cell may have an opportunity to perform radio operation.

[0062]

In such a case, while wireless communications are carried out within the cell, token ring network 1 can be simultaneously used for normal data communications. Generally the overhead control traffic resulting from transmission of high priority control message START_WIRELESS_OPER and COMPLETED_WIRELESS_OPER is a grade which can be disregarded.

[0063]

Although the token ring network was used as the underlay and has been described about this invention, note that the network composition of other common knowledge is also employable similarly. For example, the Starnet work which connected prime controller 3 as a hub node can be used similarly. As for the common appearance of the network composition in which these substitution is possible, I hear that the route of the message traffic is altogether carried out through prime controller 3.

[0064]

All the cells are overlapping with other cells of all the. In that case, the 1st method of operation-izing one by one is made into the 2nd subset, and a plan setup of many is carried out so that one cell may be operation-ized at the arbitrary predetermined times.

[0065]

As mentioned above, although this invention has described the desirable example, it should be understood for those who became skilled in the art concerned that shape and details can be changed, without deviating from the meaning and the scope of this invention.

[Brief Description of the Drawings]

[Drawing 1]

The outline with a wireless network with the duplicate communication cell which a mobile communications unit moves freely a plurality of header stations and among them of token ring LAN is shown, and it is a To figure.

[Drawing 2]

The block diagram showing one of the header stations of Drawing 1.

[Drawing 3]

The block diagram showing one of the mobile communications units of Drawing 1.

[Drawing 4]

The figure showing the response of a header station to arrival of a token with a privilege.

[Drawing 5]

The constitutional diagram of a header station including the privilege state called when receiving a token with a privilege showing a possible logical state variously.

[Drawing 6]

The figure showing two or more cellular radio network with the mobile communications unit dispersed in the duplicate cell and the cell.

[Drawing 7]

The local interference graph of the network of Drawing 6.

[Drawing 8]

The figure showing a header station group operation-ized order controlled by the prime controller of LAN.

[Drawing 9]

The flow chart which shows how to assign a header station to a group.

[Description of Notations]

1 Token Ring Communication Network 10 Move Unit 12 Header Station