Abstract:
An object of this invention is to construct a radio communication system with low cost of installation which needs no base station, and said system is a communication system for performing a radio communication by a packet  18  among numerous mobile communication stations  2  in an expandable are by providing a relay function in a mobile communication station  2  of portable type, and said each mobile communication station  2  comprises a packet reception means, a packet judging means for judging if the received packet is the self relative address or not, a relay means for transmitting the received packet when the received packet is not the self relative address and also, the received packet is not identical with the packet received in the past, a means for generating packets, and a means for transmitting the generated packet. The packet relay means transmits the received packet in a random timing.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to radio communication system and mobile communication station used for this communication system.  
         [0002]     Heretofore, as it is disclosed in the official gazette of Japanese Patent Kokai-Koho Kai 2000-49690, in order to substantially expand a communicable area by restraining a rise of system costs, a portable telephone set has been known to the public which comprises a normal reception unit for receiving communication information at normal communication time as a portable telephone set, a normal transmitting unit for transmitting the communication information at normal time, an inputting means for inputting at least a propriety of setting communication outside area, a reception unit for area outside to receive and detect an area outside code, a transmission unit for area outside to transmit the communication information at area out time, a control unit, and a control unit for performing a system control of the control unit. This mobile telephone set performs a normal communication of a reception information to its local station with a calling side in case it is located in the communicable area with a base station, and in case of time when the reception information is not to the local station, performs a relay operation by attaching a relay code, and in case it is located in area outside capable of communicating with the base station, the reception information to the self station performs a normal communication by attaching an area outside code with the calling side, and in case where it is not the reception information to the self station, performs a relay operation with the area outside by attaching a relay code.  
         [0003]     In the conventional portable telephone relay system, the existing communicable area can be expanded without bringing about an increase of the existing base stations, but the presence of the base station is indispensable, and costs for installation of the facilities is expensive, and the increased cost give a rise to burden of the costs to the subscribers. Furthermore, at an emergency time, calls concentrates upon the specific base station which tends to cause an inability of communications.  
         [0004]     An object of the present invention is to solve the foregoing problems.  
       SUMMARY OF THE INVENTION  
       [0005]     The present invention relates to a communication system for performing a radio communication by packets in numerous mobile stations in an expandable area with a provision of a relay function to portable mobile stations. Each mobile stations comprises a packet reception means, a packet judging means for judging if the received packet is self set or not, a packet relay means for transmitting the received packet when the received packet is not to the self set and the packet received is not identical with the packet received in the past, a means for generating a packet, and a means for transmitting the generated packet. The packet relay means transmits the received packet at a random timing. 
     
    
     DESCRIPTION OF DRAWINGS  
       [0006]      FIG. 1  shows a flow chart showing an operation of a communication system according to the present invention.  
         [0007]      FIG. 2  shows an explanation drawing of a packet.  
         [0008]      FIG. 3  shows a block explanation drawing showing a structure of interior of a mobile station.  
         [0009]      FIG. 4  shows a flow chart showing an operation of the communication system according to the present invention.  
         [0010]      FIG. 5  shows a flow chart showing an operation of a communication system according to the present invention.  
         [0011]      FIG. 6  shows a flow chart showing an operation of the communication system according to the present invention.  
         [0012]      FIG. 7  shows a flow chart showing an operation of the communication system according to the present invention.  
         [0013]      FIG. 8  is an explanation drawing showing an operation of the communication system according to the present invention.  
         [0014]      FIG. 9  is an explanation drawing showing an operation of the communication system according to the present invention.  
         [0015]      FIG. 10  is an explanation drawing of an operation of the communication system according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0016]     The mode of embodiment of the present invention is described in details in the following by referring to the attached drawings.  
         [0017]      FIG. 3  shows an internal structure of a mobile station  2  provided with a function of a portable telephone set used in this communication system. In the casing of the mobile station  2 , an adaptive array antenna  4  for reception and an adaptive array antenna  6  for transmission are mounted. The antenna  4  for reception is connected to a reception amplifier  8 , and the antenna  6  for transmission is connected to a transmission amplifier  10 . A data collection unit  12  is connected to an input unit (illustration is omitted) for processing audio signals such voice or the like or data and image signals.  
         [0018]     The data inputted to these input units are inputted to the data collection unit  12 , and the data collection unit  12  receives an input signal outputted from these input units, and supplies the input signals to a packet constituting unit  14 . The packet constituting unit  14  generates a packet  18  shown in  FIG. 2  on the basis of the input signals and signals from the unique word generator  18 . Also, the packet constituting unit  14  is connected to a transmission amplifier  10  by means of an encoder  20  and a modulator  22 . Reference numeral  24  shows a control unit, and an application for controlling this system and a variety of communication control programs are stored in the control unit. The control unit  24  is connected to a high precision oscillator  26 , output beam control unit  28 , random number (fluctuation) generating unit  30 , a radio wave arriving direction detector  32 , a radio wave arriving distance measuring unit  34  and a packet judging unit  36  are connected.  
         [0019]     The reception amplifier  8  is connected to a unique word detector  40  and a packet reconstituting unit  42  by means of a demodulator  36  and a decoder  38 . The packet reconstituting unit  42  reconstitues a packet by changing the data of the received packet or adding the data by the control of the control unit  24 . The data generating unit  44  converts the packet to voice or character data or image and outputs it to an output device (illustration is omitted). The packet judging unit  37  gives a decision on classification of the packets and the like by the control of the control unit  24 . A packet judging unit  36  is connected to a packet memory unit  46 , and the packet memory unit  46  is connected to the packet constituting unit  14 .  
         [0020]     Next, as shown in  FIG. 4 , a main operation of the transmission will be described by referring to a transmission main flow.  
         [0021]     The control unit  24  of the the mobile station  2  (hereinafter referred to mobile station is called briefly as MS) constitutes a packet  18  (step  2 ) by judging if there is a completed packet or not (step  1 ) in the first place once a mode of the transmission enters, controlling the packet constituting unit  14 . The packet  18  constituted by the packet constituting unit  14  comprises a header unit  48  and a data unit  50  and a data error correction unit  52  as shown in  FIG. 2 , and the header unit  48  comprises a unique word unit  54 , first departure address unit  56 , terminal address unit  58 , first departure serial No. unit  60 , relay count unit  62 , classification code unit  64 , and header error correction unit  68 . The unique word to be stored in the unique word unit  54  is used for detection of the packet, and a direction of packet (radio wave), confirmation of time difference and detection of version of the packet.  
         [0022]     The first departure address to be stored in the first departure address unit  56  is an address of the MS  2  that is initially transmitted. The first departure serial No. adds 0 to the initially transmitted packet, and adds sequentially +1 to the packet to be transmitted. The relay count is 0 when the transmission is made in the first place, and when it is relayed, adds +1. The classification code shows a kind of the packets, and 0 shows an absence of the data unit, and 1 shows a presence of the data unit. When the packet  18  is constituted in the step  2 , the control unit  24  next sets (step  3 ) a direction of beam of the antenna array  6 , magnitude of beam electric power, and a transmission parameter for determining a timing of a transmission of the beam output by the random number. Next, the control unit  24  judges (step  4 ) if a packet exists in a self space. This judgement is for safely holding other packets in a timewise and frequency-wise channel with respect to self transmission. The self space means a space around an environment of the reception antenna  4 , and when the reception antenna  4  receives the other packet, it means that the other packet is present in the self space.  
         [0023]     When the other packet is present in the self space, in case of transmitting the self packet, batting may occur between the self transmitting packet and the other packet in the self space. In case the packet is absent in the self space, the control unit  24  judges (step  5 ) if the condition of timing of transmission of the packet is fulfilled, and when it is judged as it being fulfilled, the packet  18  is transmitted (step  6 ) to the outer space by controlling a random number generating unit  30  and an output beam control unit  28  on the basis of the set transmission parameter. The timing of the transmission of the packet is determined by the random number, and the fluctuation is applied to the beam output of the array antenna  6  by this random number, and the packet is transmitted in the condition resembling the natural phenomenon. The fluctuation property wherein the timing of this transmission is not made a rule is particularly important when the MS functions as the relay repeater. In case when many MS  2  simultaneously receive specific packets and the received packets are simultaneously transmitted, the packets themselves cause an interference. The fluctuation of the packet transmission avoids this phenomenon.  
         [0024]     The operation of the MS that causes first departure of the packet transmits R request and RD request is described as follows by referring to the flow chart of  FIG. 5 .  
         [0025]     Herein, the R denotes Routing Request by the packet not attached with the data B 70  of contents of the communication such as voice or the like, and the RD denotes Routing Request &amp; Data by the packet attached with this data B 70 . The control unit  24  sets (step  1 ) the R or the RD according to the protocol of the packet when entering the R, RD first departure mode. Next, the control unit  24  sets (step  2 ) an arrival waiting time counter in the MS, and transmits (step  3 ) the packet. Next, the control unit  24  judges (step  4 ) the arriving flag in the memory in the MS is ON or not, and when it is judged affirmatively, the processing is completed. When the negative judgement is given by the step  4 , next, it is judged (step  5 ) if the arrival is within the waiting time, and when it is judged that the arrival is beyond the waiting time, an error information is applied (step  6 ) to the host application, for example, the application of conversation, and the processing is completed.  
         [0026]     The retransmission is to be determined by the application of the host layer. Next, the main flow of reception common to the case of the packet being only the header, and the case of the classification of the packet are R, RA, RD will be described by referring to  FIG. 6 . Wherein the protocol classification RA means Acknowledge (Routing Request Acknowledge).  
         [0027]     When the MS control unit  24  enters the mode of the reception, the received packet judges (step  1 ) if the unique word is contained or not, and when it judges affirmatively, the packet is demodulated (step  2 ). Next, the control unit  24  controls a decoder  38 , and performs (step  3 ) the decoding of a header unit  48  and the error correction, and analyzes (step  4 ) the header unit  48 .  
         [0028]     Next, the control unit  24  judges (step  5 ) if the processing is to be interrupted or not, and when the reasons for the interruption are recognized such as the presence of the error in the packet, or the header only is found and no data unit is present, or the packets are duplicated, or the number of relays in the packets exceeds the set value, the processing is interrupted. In case these reasons for the interruption are not found, performs (step  6 ) the decoding of the data and the error correction, and performs (step  7 ) the analysis of the data unit.  
         [0029]     The operation of the analysis of the header unit will be described by referring to the  FIG. 7 .  
         [0030]     The control unit  24  judges (step  1 ) if the unique word is established or not on the basis of a signal of a unique word detector  40  when the reception mode enters, and when the affirmative judgement is made, the packet judging unit  37  judges (step  2 ) if there is an identical packet in a packet memory unit  46 . The presence or absence of the identical packet checks three elements of the packets such as the first departure of the packet, terminal address, first departure serial No.  
         [0031]     Next, the received packet is recorded (step  3 ) in the packet memory unit  46 .  
         [0032]     Next, the control unit  24  judges if the packet has the self relative address or not, and when the affirmative judgement is made, the processing continue mode goes on. When the negative judgement is made in step  4 , the control unit  24  judges (step  5 ) if the packet exceeds a maximum relay count by the packet judging unit  37 . When the negative judgement is made by the control unit  24 , a packet retransmission request is transmitted to the control unit  24  from the packet judging unit  37 . When this request is sent to the control unit  24 , the control unit  24  shifts (processing continues) to the transmission processing of the flow chart as shown in  FIG. 4 .  
         [0033]     Next, the operation of sending the acknowledge with the protocol of RA when the protocol classification of the self relative packet is R will be described by referring to the flow chart of  FIG. 1 .  
         [0034]     When the MS receives the packet  18  on the basis of the unique word by the reception antenna  4 , the control unit  24  judges (step  1 ) if the packet is established or not. The establishment of the packet in this stage explains the condition where the unique word is established, and the error of the packet is corrected, and the data is totally confirmed. When the packet is established, next, the control unit  24  judges (step  2 ) if the identical packet is present in the packet memory unit  46 . The identical packet confirms that all of the first departure address, terminal address, and first departure serial No. are entirely identical.  
         [0035]     When the identical packet is not present in the packet memory unit  46 , the control unit  24  judges (step  3 ) if the received packet is the self relative address or not from the data of the terminal address  58  of the packet  18 , and if it is the self relative packet, the packet is stored (step  4 ) in the packet memory unit  46 . Next, the control unit  24  judges (step  5 ) if a protocol classification unit  72  in a data unit  50  of the received packet is “R” or not. In the protocol classification, there are R, RD, RA, and R (request) or RD (request with data) is used as a pair with the protocol classification RA (acknowledge). When the control unit  24  judges (step  6 ) that the protocol classification of the packet is not “R”, next, judges (step  7 ) if the protocol classification is “RD”, namely, the request with call data or not, and when the affirmative judgement is made, the call data B 70  is stored (step  8 ) in the memory, and shifts to the step  6 .  
         [0036]     When the protocol classification is not “RD”, the protocol classification judges (step  9 ) if it is “RA” or not and the affirmative judgement is made, the control unit  24  sets the arrival flag in the memory ON, and stores (step  10 ) the data. When the affirmative judgement is made by the control unit  5  in the judgement step  5 , next, sets “RA” in the protocol classification unit  72  as shown in  FIG. 2 (D), three elements of the header (first departure address, terminal address, first departure serial No.) stored in the packet memory unit  46  is set in the data unit A 50  of the received packet to constitute (step  6 ) the packet  18 .  
         [0037]     Next, the control unit  24  transmits (step  15 ) the packet. When the control unit  24  judges the negative in the foregoing step  3 , next, judges (step  11 ) if the protocol classification of the received packet is “RA” or not. When the affirmative judgement is made, next, the control unit  24  retrieves the identical packet received in the past from the memory, and changes a just before transmitted address  74  of the identical packet to a next receiving address  76  of the packet of the received RA. In case the packet is not present, hoists (step  12 ) the error flag. Next, the control unit  24  judges (step  13 ) if it is the error or not, and when the negative judgement is made, reconstitutes (step  14 ) the packet and transmits (step  15 ) the packet.  
         [0038]     Next, the basic routing algorithm will be described by referring to  FIG. 8 .  
         [0039]     When the MS  2  of No. 0 transmits the packet  18  whose protocol classification is R to the address, the MS  2  of No. 4, the packet  18  is received at the MS  2  of No. 1 located nearby, and the contents of the packet are stored in the memory at the address, and the relay count unit  62  of the packet  18  is made as “1”, and (just before) transmitted address unit  74  is made as the address of the MS  2  of No. 1. In case the next receiving address unit  76  of the packet  18  is “ALL”, it is the broadcasting. The MS  2  of No. 1 transmits the packet  18  that is reconstituted into this new data.  
         [0040]     The peripheral MS  2  of No. 2 that receives the transmitted packet transmits the packet  18  by performing the similar processing. The relay count unit  62  of this packet  18  is renewed to “2”. The MS of No. 3 that receives the packet  18  performs the similar processing to transmit the packet  18 . The packet  18  is relayed by the peripheral MS  2  of No. 3 and arrives the MS  2  of No 4 of the terminal address.  
         [0041]     When the MS  2  of No. 4 receives the self relative address packet  18 , the packet  18  of the acknowledge (RA) is reconstituted wherein the MS of the self is made as the first departure address and the MS of No. 0 is made as the address, and the next receiving address  76  is made as No. 3 as shown in the drawing, and is transmitted towards the MS of No. 3 of the next receiving address. This packet  18  is in the drawing, and is transmitted towards the MS of No.3 of the next receiving address. This packet  18  is provided with a data unit A 50  comprising the protocol classification “RA”, just before transmission address “No. 4”, next receiving address “No. 3”, first departure address “No. 0”, and terminal address “No. 4”, and first departure serial “No.N”.  
         [0042]     This first departure serial No. is constructed in that “O” is added to the packet that is initially transmitted and and +1 is added to the different packets that are sequentially transmitted. The packet  18  of the protocol classification “RA” that is transmitted from the MS  2  of No. 4 has the MS  2  of No. 0 as the terminal address takes up a return route of counter direction against ongoing route of the packet  18  of the protocol classification “R” forming a pair with the foregoing packet  18 , and is sequentially relayed like the MS of No. 3, the MS of No. 2 and the MS of No. 1, and reaches the MS of No. 0.  
         [0043]     In the returning route, each MS of No. 3, No. 2 and No. 1 plays a role of router, and the just before transmission address  74  of the packet  18  to be transmitted from the MS of No. 1 is reconstituted as the No. 1 and next receiving address as “No. 0” as shown in the drawing. In  FIG. 8 , in case where the packet of the protocol classification “RA” is received in the MS other than the established routing, this MS hoists the error flag as shown in the step  2  of  FIG. 1 , and completes the reception processing, and does not perform the relay operation.  
         [0044]     The foregoing operation will be described in the following by referring to  FIG. 10  with reference to the case of exchanging the voice data.  
         [0045]     In order to establish the routing between the first departure MSA station and the terminal MSB station, the MSA station of the first departure station transmits (stage  1 ) acknowledge request, namely, packet of R to the MAB station of the terminal station. The MSB station of the terminal station produces the packet RA for acknowledge and transmits (stage  2 ) the packet RA towards the MSA station that is the first departure station of R forming a pair with the foregoing station when receiving the packet R. As the routing is established in the stage  2 , the MSA station transmits (stage  3 - 1 ) the package RD contained in the voice towards the MSB station. The MSB station transmits (stage  3 - 2 ) the reply RA against the package RD towards the MSA station. Likewise, the MSA station transmits (stage  4  . . . n) the packet RD attached with the voice data to the MSB station for necessary number of packets. For the exchange of voices between the MSA station and the MSB station, the transmission of the voices of counter direction towards the MSA station from the MSB station becomes necessary. The exchange of the voice data is accomplished (stage n+1) by arranging the packet RD with the voice data to move from the MSB station towards the MSA station.  
         [0046]     Next, the transmission of only the part of the header unit of the packet will be described by referring to  FIG. 9 .  
         [0047]     This transmission is carried out smoothly for the actual communication to be conducted subsequently with the intention of an initial setting as the network.  
         [0048]     The MS  2  of No. 0 of the first departure is arranged as shown in the drawing that the header unit of the packet  18  is set like the first departure address unit  56  to be “No. 0”, terminal address unit  58  is “No. 50”, first departure serial No. unit  60  is “No. 0”, relay count unit  62  is “0” and classification code unit  64  is “0”.  
         [0049]     This classification code unit  64  shows the kinds of the packet, and “0” shows “no data” and “1” shows “with data”. The packet  18  transmitted from the MS  2  of No. 0 reaches the MS  2  of No. 50 through the various routes as shown in the drawing but the MS  2  of No. 50 becomes possible to set the shortest route with the MS  2  of No. 0 by the count value of a relay count unit  62  in the reached packet  18 .  
         [0050]     The present invention has been constructed as described in the foregoing so that this invention needs no base station, and the cost of the entire system can be made extremely low.