JP2016152435A - Packet communication base station and radio terminal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure a sufficient time to communicate packet information.SOLUTION: A base station transmits a beacon 16 repeatedly at a transmission period Tp. One time slot is set in a time zone after one beacon is transmitted and before a next beacon 16 is transmitted. On receiving uplink packet information 18 from a terminal device in an uplink time zone US, the base station includes acknowledgement information, destined to a transmission source terminal device of the uplink packet information, in the beacon 16 to be transmitted in the next time slot. The base station extracts a transmission source address from the uplink packet information, to include the transmission source address, as a destination address, in the acknowledgement information. When the terminal device receives the beacon 16, if acknowledgement information destined to the self-device is included in the beacon 16, the terminal device recognizes from the acknowledge information that the uplink packet information is received in the base station.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a packet communication base station, and more particularly to a technique for transmitting acknowledgment information for packet information transmitted from a terminal device.

  A communication system in which a plurality of terminal devices perform wireless communication with a base station is widely used. Generally, in such a communication system, a base station is connected to a wired communication network such as the Internet. Each terminal device wirelessly transmits packet information to the base station, and the base station transmits the packet information to the wired communication network. Further, the base station wirelessly transmits packet information received from the wired communication network to the terminal device. As a result, the terminal device transmits and receives image information, audio information, character information, and the like to and from a device that is communicatively connected to the wired communication network.

  The following Patent Documents 1 to 3 describe communication technologies related to the present invention. Patent Document 1 describes a communication system including a base station device and a plurality of terminal devices. In this communication system, a base station device transmits a beacon frame that defines transmission / reception timing of a data frame to each terminal device. Each terminal device that has received the beacon frame transmits a data frame to the base station at a timing according to a value included in the beacon frame. As a result, the plurality of terminal apparatuses transmit data frames at different timings, and collision of frames in the communication system is avoided.

  Patent Document 2 describes a wireless communication system in which wireless communication is performed between a plurality of wireless communication devices. This document describes a process in which, when any wireless communication device transmits a multicast frame, each wireless communication device that has received the multicast frame transmits an acknowledgment frame (acknowledgment frame) to the transmission source wireless communication device. Has been.

  Patent Document 3 describes a communication system including a management terminal and a plurality of client terminals connected to the management terminal via a network. In this communication system, a management terminal transmits packet data for causing a client terminal to execute synchronization processing and bandwidth allocation processing. Each client terminal returns packet data for responding to the packet data to the management terminal.

JP 2011-49824 A JP 2013-197928 A JP 2012-199745 A

  In a communication system in which a plurality of terminal apparatuses perform wireless communication with a base station, transmission of reception of beacon packet information and various packet information for executing synchronization processing between each terminal apparatus and the base station is transmitted. Various packet information such as acknowledge packet information for transmitting to the original is transmitted and received. Therefore, when many terminal devices are used, it is difficult to secure the time required for packet information communication, and packet information congestion may occur.

  An object of the present invention is to secure a sufficient time for performing communication of packet information.

  The present invention is included in the packet information, a beacon transmission unit that repeatedly transmits a beacon that causes the terminal device to recognize operation timing, a reception unit that receives packet information transmitted from the terminal device in response to the beacon, and the packet information An extraction unit that extracts terminal identification information; and an information addition unit that includes acknowledgment information for the terminal device to which the terminal identification information is assigned in the beacon transmitted after the packet information is received. It is characterized by.

  Preferably, the receiving unit receives the packet information transmitted from each of the plurality of terminal devices in response to the beacon, and the extracting unit extracts the terminal identification information included in each of the packet information Then, the information adding unit includes acknowledge information corresponding to each terminal identification information in the beacon.

  Preferably, the information adding unit includes acknowledgment information in one beacon for the terminal identification information up to a predetermined upper limit among the plurality of terminal identification information, and the packet communication base station Is an acknowledge packet generating unit that generates acknowledge packet information for the terminal device corresponding to the remaining terminal identification information that did not include acknowledge information in the beacon, and transmission timing of the beacon for the acknowledge packet information And an acknowledge packet transmitter for transmitting at different timings.

  Preferably, one transmission cycle for the beacon includes a downlink time zone in which the packet communication base station transmits information and an uplink time zone in which the packet communication base station receives information, The acknowledge packet transmitting unit transmits the acknowledge packet information in a time zone within the downlink time zone and after the beacon is transmitted.

  Preferably, the beacon includes timing information that defines a downlink time zone in which the packet communication base station transmits information and an uplink time zone in which the packet communication base station receives information.

  Preferably, the beacon includes downlink information which is downlink information and indicates a timing at which the packet communication base station transmits downlink packet information destined for the terminal device.

  Desirably, it comprises a communication status detection unit for detecting a communication status for one transmission cycle of the beacon, and the beacon transmission unit is a transmission condition according to the communication status, in a transmission cycle after the transmission cycle. The beacon is transmitted.

  A wireless terminal device that includes the terminal device and performs wireless communication with the packet communication base station includes: a beacon receiving unit that receives the beacon; and the uplink based on the timing information included in the beacon. You may provide the time slot | zone determination part which calculates | requires a time slot | zone, and the packet transmission part which transmits the said packet information in the said uplink time slot | zone.

  A wireless terminal device that includes the terminal device and performs wireless communication with the packet communication base station, the beacon receiving unit that receives the beacon, and the timing based on the downlink information included in the beacon, A downlink packet receiving unit that receives downlink packet information, and a power supply control unit that turns off the power supply of a circuit included in the terminal device from when the beacon is received until reception of the downlink packet information is started And may be provided.

  For the packet communication, including the terminal device, wherein the beacon transmitting unit transmits a plurality of the beacons having different frequencies within one transmission period, and the receiving unit receives the plurality of packet information having different frequencies. A wireless terminal device that performs wireless communication with a base station includes a beacon receiving unit that receives the beacon and a packet transmitting unit that transmits the packet information, and receives the beacon over a predetermined number of transmission cycles. When the unit does not receive the beacon, the beacon receiving unit may change the reception frequency of the beacon, and the packet transmission unit may change the transmission frequency of the packet information.

  According to the present invention, it is possible to secure a sufficient time for performing packet information communication.

It is a figure which shows the structure of the communication system which concerns on this invention. It is a figure which shows notionally the relationship between a beacon and a time slot. It is a figure which shows the timing with which packet information is transmitted / received in a base station. It is a figure which shows the timing which the beacon and downlink packet information containing downlink information are transmitted from a base station. It is a figure which shows the timing in case transmission / reception of packet information is performed using each frequency channel. It is a figure which shows the timing which the beacon and downlink packet information containing downlink information are transmitted from a base station. It is a figure which shows the process which carries out the radio transmission of the beacon of each frequency channel simultaneously. It is a figure which shows the process which transmits acknowledge packet information separately from a beacon. It is a figure which shows a process when the interference wave with respect to a 2nd frequency channel arrives. It is a figure which shows the example of the hardware of a base station. It is a figure which shows the example of the hardware of a terminal device.

(1) Overview of Operation of Communication System FIG. 1 shows the configuration of a communication system according to the present invention. The communication system includes a wired communication network 10, a base station 12, and a plurality of terminal devices 14. The wired communication network 10 is a telecommunication line such as the Internet, for example.

  The base station 12 is assigned an address as base station identification information, and each terminal device 14 is assigned an address as terminal identification information. Transmission / reception of packet information between the base station 12 and each terminal device 14 is performed using addresses assigned thereto.

  The base station 12 relays packet information between the wired communication network 10 and the terminal device 14. That is, the base station 12 receives the packet information wirelessly transmitted from the terminal device 14 and transmits the packet information to the wired communication network 10. The base station 12 receives packet information from the wired communication network 10 and wirelessly transmits the packet information to the terminal device 14 that is the destination of the packet information.

  Substantial information such as image information, audio information, and character information transmitted from the terminal device 14 to the base station 12 is transmitted by uplink packet information. Further, substantial information transmitted from the base station 12 to the terminal device 14 is transmitted by downlink packet information. A beacon is transmitted from the base station 12 to each terminal device 14 in order to define the timing of transmitting the uplink packet information from the terminal device 14 to the base station 12 and transmitting the downlink packet information from the base station 12 to the terminal device 14.

  The base station 12 repeatedly transmits a beacon to each terminal device 14 at a predetermined transmission cycle. The beacon is packet information for defining transmission / reception timing of various packet information. By transmitting a beacon, a time slot for transmitting and receiving packet information between the base station 12 and each terminal device 14 is set.

  FIG. 2 conceptually shows the relationship between the beacon 16 and the time slot S. The horizontal axis indicates time t. In the example shown in FIG. 2, the timing at which the base station transmits the beacon 16 is the start timing of the time slot S. The transmission period Tp of the beacon 16 is the time length of each of a plurality of time slots S that are continuous in time series.

  Each time slot S includes a downlink time zone DS for transmitting packet information from the base station to the terminal device, and an uplink time zone US for transmitting packet information from the terminal device to the base station. The beacon 16 includes timing information that defines the downlink time zone DS and the uplink time zone US. The terminal device that has received the beacon 16 recognizes the downlink time zone DS and the uplink time zone US based on the timing information included in the beacon 16.

(2) Basic Communication Processing (2-1) Time Slot Setting FIG. 3 shows the timing at which packet information is transmitted and received at the base station. The base station has a clock for counting time and operates at a timing according to the count by the clock. The base station repeatedly transmits the beacon 16 at the transmission cycle Tp. In the example shown in FIG. 3, one time slot is set in a time zone from when one beacon is transmitted until the next beacon 16 is transmitted. That is, time slots S (j), S (j + 1), S (j + 2),... Are set by repeatedly transmitting the beacon 16. Here, j is a positive integer.

  The base station includes timing information in the beacon 16 when generating and transmitting each beacon 16. The timing information includes a delay time δ, a transmission cycle Tp, and a downlink ratio η. The delay time δ is a delay time from the start time of the time slot until the beacon 16 is transmitted. In the example shown in FIG. 3, the delay time δ is zero. The downlink ratio η is a positive number smaller than 1. When the transmission cycle Tp is stored in each terminal device as a constant value, the timing information does not necessarily include the transmission cycle Tp.

  The terminal device includes a clock for counting time, and recognizes the downlink time zone DS and the uplink time zone US by the following process. That is, when receiving the beacon 16, the terminal device recognizes that the time zone from the start time of the time slot until η · Tp elapses is the downlink time zone DS, and from the end time of the downlink time zone DS ( The time zone until 1−η) · Tp elapses is recognized as the uplink time zone US.

  Here, the start time of the time slot is the time before the delay time δ from the time when the beacon 16 is received by the terminal device. However, the propagation time from when the beacon 16 is transmitted from the base station to when the beacon 16 is received by the terminal device can be approximated to zero. In this way, each terminal device recognizes the downlink time zone DS and the uplink time zone US in the time slot each time it receives a beacon 16.

(2-2) Transmission / reception of uplink packet information Each terminal device transmits uplink packet information in the uplink time zone US when transmitting the uplink packet information to the base station. FIG. 3 shows that two uplink packet information 18 transmitted from two terminal apparatuses are received by the base station in the uplink time zone US in the time slot S (j). Further, it is shown that three uplink packet information 18 transmitted from three terminal apparatuses are received by the base station in the uplink time zone US in the time slot S (j + 1). Further, it is shown that one uplink packet information 18 transmitted from one terminal apparatus is received by the base station in the uplink time zone US in the time slot S (j + 2).

  The base station generates packet information including the same information as the information included in the uplink packet information 18, and transmits the packet information to the wired communication network.

  When the base station receives the upstream packet information 18, the beacon 16 transmitted in the next time slot includes acknowledgment information destined for the terminal device that has transmitted the upstream packet information 18. The acknowledge information is information for notifying the transmission source terminal device that the upstream packet information 18 has been received. The base station extracts the source address from the upstream packet information 18 and includes the source address in the acknowledge information as the destination address.

  When uplink packet information 18 is transmitted from a plurality of terminal devices, the base station extracts a source address from each of the plurality of uplink packet information 18 transmitted from the plurality of terminal devices. Then, each piece of acknowledgment information destined for each terminal device of the transmission source is included in one beacon 16 that is transmitted in the next time slot. In this case, the base station includes the address of the transmission source terminal device as the destination address in each acknowledgment information.

  When the beacon 16 includes acknowledge information addressed to itself, the terminal device that has received the beacon 16 recognizes that the upstream packet information 18 transmitted earlier is received by the base station based on the acknowledge information.

(2-3) Transmission / reception of downlink packet information When the base station transmits downlink packet information with a specific terminal device as a destination, the base station beacons downlink information that associates the address of the destination terminal device with the slot designation number M. Included. The slot designation number M indicates that downlink packet information is transmitted to the Mth time slot from the time slot next to the time slot in which the beacon including the slot designation number M is transmitted.

  FIG. 4 shows a timing at which a beacon 16L including downlink information is transmitted from the base station, and further, downlink packet information 20 is transmitted from the base station. The same items as those shown in FIG. 3 are denoted by the same reference numerals, and the description thereof is omitted.

  The base station transmits a beacon 16L including downlink information in the downlink time zone DS in the time slot S (j). Then, the downlink packet information 20 is transmitted in the downlink time zone DS in the time slot S (j + M).

  Among the terminal devices that have received the beacon 16L including the downlink information, the terminal device whose own address is included in the downlink information, according to the slot designation number M, is the downlink time zone in the time slot S (j + M). The downlink packet information 20 transmitted from the base station to the DS is received.

  Note that the terminal device whose own address is included in the downlink information, from the time slot S (j + 1) next to the time slot S (j) that received the beacon 16L to the time slot S (j + M-1). During this time, the power supply power of the circuit that receives the packet information may be turned off to stand by. Thereby, power consumption in the terminal device is reduced.

(2-4) Effect obtained by communication system In a communication system, a beacon is repeatedly transmitted from a base station. The terminal device recognizes the downlink time zone and the uplink time zone in the time slot by receiving the beacon. Packet information is transmitted from the base station to the terminal device in the downlink time zone, and packet information is transmitted from the terminal device to the base station in the uplink time zone. This prevents the terminal device from transmitting packet information to the base station while the base station is transmitting packet information.

  Further, the beacon includes acknowledge information for uplink packet information transmitted from the terminal device. Thereby, the number of packet information transmitted from the base station to the terminal device is reduced, and sufficient time for communication between the base station and the terminal device is ensured.

(3) Communication using a plurality of frequency channels (3-1) Time slot setting The base station and each terminal device may transmit and receive packet information using a plurality of frequency channels. In the following description, a case where three frequency channels are used will be described, but the number of frequency channels used is arbitrary. 5 (F1) to (F3) show timings when packet information is transmitted and received using each of the first frequency channel F1, the second frequency channel F2, and the third frequency channel F3. ing. The same reference numerals are given to the same items as those shown in FIG. 3 and FIG. 4, and the description thereof is omitted.

  The base station repeatedly transmits the beacon 16-1 of the first frequency channel F1 at the transmission cycle Tp. In addition, the base station transmits the beacon 16-2 of the second frequency channel F2 after a delay time δ1 after starting the transmission of the beacon 16-1 of the first frequency channel F1. Further, the base station transmits the beacon 16-3 of the third frequency channel F3 after the delay time δ2 after the transmission of the beacon 16-1 of the first frequency channel F1 is started. In the following description, the beacons 16-3 in the first frequency channel F1, the second frequency channel F2, and the third frequency channel F3 are referred to as the first frequency beacon 16-1, the second frequency beacon 16-2, and the third frequency beacon, respectively. It is assumed that the frequency beacon 16-3.

  In this way, the base station repeatedly transmits the first frequency beacon 16-1, the second frequency beacon 16-2, and the third frequency beacon 16-3 at the transmission cycle Tp. One time slot is set in a time zone from when a beacon is transmitted for each frequency until the next beacon is transmitted. The time slot is common for all frequency channels. Also, the downlink time zone DS and the uplink time zone US in each time slot are also common for all frequency channels.

  The terminal device selects one frequency channel from the first frequency channel F1, the second frequency channel F2, and the third frequency channel F3. The terminal device recognizes the downlink time zone DS and the uplink time zone US in each time slot based on the beacon received by the frequency channel selected by the terminal device, and transmits and receives packets.

(3-2) Uplink packet information When transmitting the uplink packet information to the base station, the terminal apparatus transmits the uplink packet information in the uplink time zone US in the frequency channel selected by itself. The base station can simultaneously receive uplink packet information of different frequencies in the uplink time zone US.

  5 (F1) to (F3) show timings at which uplink packet information is transmitted from the terminal device and uplink packet information is received by the base station in the first frequency channel F1 to the third frequency channel, respectively. ing. That is, in FIG. 5 (F1), two uplink packet information 18-1 transmitted from two terminal apparatuses in the uplink time zone US in the time slot S (j) are received by the base station. It is shown. Also, it is shown that two uplink packet information 18-1 transmitted from two terminal apparatuses are received by the base station in the uplink time zone US in the time slot S (j + 1). Further, it is shown that one uplink packet information 18-1 transmitted from one terminal apparatus is received by the base station in the uplink time zone US in the time slot S (j + 2).

  FIG. 5 (F2) shows that three uplink packet information 18-2 transmitted from three terminal apparatuses are received by the base station in the uplink time zone US in the time slot S (j). Has been. In addition, it is shown that two uplink packet information 18-2 transmitted from two terminal apparatuses are received by the base station in the uplink time zone US in the time slot S (j + 1). Further, it is shown that one uplink packet information 18-2 transmitted from one terminal apparatus is received by the base station in the uplink time zone US in the time slot S (j + 2).

  FIG. 5 (F3) shows that two uplink packet information 18-3 transmitted from two terminal apparatuses are received by the base station in the uplink time zone US in the time slot S (j). Has been. Also, it is shown that one uplink packet information 18-3 transmitted from one terminal apparatus is received by the base station in the uplink time zone US in the time slot S (j + 1). Further, it is shown that two uplink packet information 18-3 transmitted from two terminal apparatuses are received by the base station in the uplink time zone US in the time slot S (j + 2).

(3-3) Downlink Packet Information In FIG. 6 (F1), the first frequency beacon 16-1L including downlink information is transmitted from the base station, and further, downlink packet information 20-1 is transmitted from the base station. Timing is shown. The same matters as those shown by the reference numerals shown in FIG. 5 are given the same reference numerals and the description thereof is omitted.

  The base station transmits the first frequency beacon 16-1L including downlink information in the downlink time zone DS in the time slot S (j). Then, the downlink packet information 20-1 of the first frequency channel F1 is transmitted in the downlink time zone DS in the time slot S (j + M).

  Among the terminal devices that have received the first frequency beacon 16-1L in the downlink time zone DS in the time slot S (j), the terminal device whose own address is included in the downlink information is the number M of slot designations. Accordingly, the downlink packet information 20-1 of the first frequency channel F1 transmitted from the base station in the downlink time zone DS in the time slot S (j + M) is received.

  Note that the terminal device whose own address is included in the downlink information starts from the time slot S (j + 1) next to the time slot S (j) that received the first frequency beacon 16-1L, to the time slot S (j + M Until -1), the power for the circuit for receiving the packet information may be turned off and may be on standby. Thereby, power consumption in the terminal device is reduced.

  FIG. 6 (F3) shows the timing at which the third frequency beacon 16-3L including downlink information is transmitted from the base station, and further, the downlink packet information 20-3 is transmitted from the base station. The operations of the base station and the terminal device in this case are the same as the operations in the first frequency channel F1 shown in FIG. 6 (F1).

(3-4) Process of simultaneously transmitting beacons of different frequency channels In the above-described embodiment, the first frequency beacon 16-1, the second frequency beacon 16-2, and the third frequency beacon 16-3 are transmitted at different timings. The Depending on the configuration of the transmission circuit of the base station, these beacons may be transmitted simultaneously. In FIG. 7, when the first frequency beacon 16-1, the second frequency beacon 16-2, and the third frequency beacon 16-3 are repeatedly wirelessly transmitted at the transmission cycle Tp, the timing at which each piece of packet information is transmitted and received is shown. It is shown. The same matters as those shown by the reference numerals shown in FIG. 5 are given the same reference numerals and the description thereof is omitted.

  In each of the first frequency channel F1, the second frequency channel F2, and the third frequency channel F3, one time slot is set in a time zone from when one beacon is transmitted until the next beacon is transmitted. The Except for the beacon transmission timing in each frequency channel, the processing executed in the base station and the terminal device is the same as in the embodiment shown in FIG.

(3-5) Acknowledgment Packet Information As described above, when the base station receives the uplink packet information, the base station transmits the acknowledgment information addressed to the terminal device that has transmitted the uplink packet information to the beacon transmitted in the next time slot. Include. When uplink packet information is transmitted from a plurality of terminal devices, the base station includes each piece of acknowledgment information destined for each terminal device as a transmission source in one beacon.

  However, there is an upper limit on the number of acknowledge information that can be included in one beacon. Therefore, when the number of uplink packet information received in one uplink time zone exceeds a predetermined upper limit, all the acknowledgment information can be included in one beacon transmitted in the next time slot. Can not. Therefore, the base station transmits acknowledge packet information including acknowledge information that could not be included in the beacon, in addition to the beacon, in the time slot next to the uplink time slot.

  In FIG. 8 (F1), the acknowledgment packet information 22-1 is transmitted separately from the first frequency beacon 16-1 in the downlink time zone DS in the time slot S (j + 1) for the first frequency channel F1. It is shown. In FIG. 8 (F3), for the third frequency channel F3, the acknowledge packet information 22-3 is transmitted separately from the third frequency beacon 16-3 in the downlink time zone DS in the time slot S (j + 1). It is shown. Here, it is assumed that the number of acknowledge information that can be included in one beacon is five. The same matters as those shown by the reference numerals shown in FIG. 5 are given the same reference numerals and the description thereof is omitted.

  In the example shown in FIG. 8 (F1), seven uplink packet information 18-1 transmitted from seven terminal apparatuses are received by the base station in the uplink time zone US in the time slot S (j). Has been. Since the number of acknowledge information that can be included in one beacon is 5, acknowledge information corresponding to the two upstream packet information 18-1 cannot be included in the first frequency beacon 16-1.

  The base station transmits the first frequency beacon 16-1 including the acknowledge information corresponding to the five uplink packet information 18-1 in the downlink time zone DS in the time slot S (j + 1). Further, the base station transmits acknowledge packet information 22-1 including each piece of acknowledge information corresponding to the remaining two upstream packet information 18-1 in the downlink time zone DS in the time slot S (j + 1). . In this case, the base station may include, in the first frequency beacon 16-1, notice information indicating the timing for transmitting the acknowledge packet information 22-1 following the first frequency beacon 16-1. The terminal device that has received the first frequency beacon 16-1 receives the acknowledge packet information 22-1 according to the timing indicated by the advance notice information included therein.

  In the example shown in FIG. 8 (F3), six uplink packet information 18-3 transmitted from six terminal apparatuses are received by the base station in the uplink time zone US in the time slot S (j). Has been. Since the number of acknowledge information that can be included in one beacon is 5, acknowledge information corresponding to one uplink packet information 18-3 cannot be included in the third frequency beacon 16-3.

  The base station transmits the third frequency beacon 16-3 including each piece of acknowledge information corresponding to the five uplink packet information 18-3 in the downlink time zone DS in the time slot S (j + 1). Further, the base station transmits acknowledge packet information 22-3 including the acknowledge information corresponding to the remaining one upstream packet information 18-3 in the downlink time zone DS in the time slot S (j + 1). In this case, the base station may include in the third frequency beacon 16-3 notice information indicating the timing of transmitting the acknowledge packet information 22-3 following the third frequency beacon 16-3. The terminal device that has received the third frequency beacon 16-3 receives the acknowledge packet information 22-3 according to the timing indicated by the notice information included therein.

  The base station may determine the downlink ratio η to be transmitted in the time slot S (j + 1) according to the number of received uplink packet information. For example, the downlink ratio η may be increased as the number of uplink packet information increases. The base station may make the downlink ratio η transmitted in the time slot S (j + 1) larger than the downlink ratio η transmitted in the time slot S (j). Thereby, the downlink time zone DS in the time slot S (j + 1) becomes longer than the downlink time zone DS in the time slot S (j), and a time for transmitting the acknowledge packet information is secured.

  In this way, when the base station cannot include all of a plurality of acknowledgment information for a plurality of terminal apparatuses that transmitted uplink packet information in the uplink time zone in one beacon, Acknowledge packet information is transmitted. This ensures communication between the base station and the terminal device.

  Note that there is an upper limit to the number of acknowledge information that can be included in one acknowledge packet information. Therefore, acknowledge information that cannot be included in the acknowledge packet information may occur. In this case, the base station may further include the remaining acknowledge information in a beacon transmitted after transmitting the acknowledge packet information.

(3-6) Change of frequency channel The base station repeatedly transmits each of the first frequency beacon, the second frequency beacon, and the third frequency beacon. On the other hand, each terminal device receives a beacon of a frequency channel selected by itself. When an interference wave arrives at the communication system, communication between the base station and each terminal device is hindered by the interference wave, making it difficult for the terminal device to receive a beacon. When the terminal device cannot receive a beacon over a predetermined number of consecutive time slots, the terminal device changes the frequency channel and receives the beacon.

  FIG. 9 shows the timing of packet information transmitted and received at the base station when an interference wave for the second frequency channel F2 arrives in two consecutive time slots S (j) and S (j + 1). Has been. In this example, the terminal device changes the frequency channel when the beacon cannot be received over two consecutive time slots. The same matters as those shown by the reference numerals shown in FIG. 5 are given the same reference numerals and the description thereof is omitted.

  The terminal device that has selected the second frequency channel F2 cannot receive the second frequency beacon 16-2 in the time slots S (j) and S (j + 1) due to the arrival of the interference wave. In this case, the terminal apparatus changes the frequency channel from the second frequency channel F2 to the first frequency channel F1 or the third frequency channel F3 in the time slot S (j + 2).

  For example, the three terminal devices that have selected the second frequency channel F2 cannot receive the second frequency beacon 16-2 due to the influence of the interference wave 24 in the time slot S (j). Therefore, the uplink packet information A, B, and C that should have been originally transmitted in the uplink time zone US in the time slot S (j) in the second frequency channel F2 are not transmitted from each terminal device. .

  FIG. 9 shows an example in which two of the three terminal devices change the frequency channel to the first frequency channel F1. These two terminal devices receive the first frequency beacon 16-1 in the time slot S (j + 2), and receive the uplink packet information 18-B and 18-C of the first frequency channel F1 in the uplink time zone US. Send. Thus, the uplink packet information 18-B and 18-C are transmitted from the two terminal apparatuses in the time slot S (j + 2) in the first frequency channel F1 instead of the time slot S (j) in the second frequency channel F2. The

  The remaining one of the three terminal devices that have selected the second frequency channel F2 changes the frequency channel to the third frequency channel F3. This terminal apparatus receives the third frequency beacon 16-3 in the time slot S (j + 2), and transmits the uplink packet information 18-A of the third frequency channel F3 in the uplink time zone US. Thus, the uplink packet information 18-A is transmitted from one terminal apparatus in the time slot S (j + 2) in the third frequency channel instead of the time slot S (j) in the second frequency channel.

  In the above description, the process in which the terminal device changes the frequency channel when the beacon cannot be received over a predetermined number of consecutive time slots has been described. Even if the terminal device cannot receive the beacon in a certain time slot, it may not change the frequency channel if it can receive the acknowledge packet information. In this case, when neither the beacon nor the acknowledge information can be received over a predetermined number of consecutive time slots, the terminal device changes the frequency channel.

  According to such processing, even if communication between the base station and the terminal apparatus is hindered by interference waves or the like in a certain time slot in a certain frequency channel, the terminal apparatus Change the frequency channel. This ensures communication between the base station and the terminal device.

  In addition, when the base station detects that the communication status is not good in a certain time slot in any frequency channel, the frequency channel in which the communication status is not good in the next time slot or subsequent time slots. The beacon transmission conditions may be changed. For example, the base station detects the communication status by detecting the reception intensity of interference waves, the reception intensity of packet information transmitted from the terminal apparatus, the presence / absence of packet information transmitted from the terminal apparatus, and the like. The beacon transmission conditions include a delay time δ from the start time of the time slot, the number of times a beacon is transmitted in the downlink time zone in one time slot, and the like. For example, when it is detected that the communication status is not good in a certain frequency channel, the communication status is increased by increasing the number of transmissions in one time slot for the beacon of that frequency channel compared to the beacons of other frequency channels. A beacon of a poor frequency channel is preferentially transmitted.

  According to such processing, even if communication between the base station and the terminal apparatus is hindered by arrival of interference waves in a certain time slot, the beacon transmission condition is changed in the subsequent time slot. The This ensures communication between the base station and the terminal device.

(4) Base Station Hardware FIG. 10 shows an example of the base station 12 hardware. The base station 12 includes a wired communication interface 24, a wireless circuit 26, an information processing unit 28, and a storage unit 30. The wired communication interface 24 connects the information processing unit 28 to a wired communication network. The wired communication interface 24 transmits the packet information output from the information processing unit 28 to the wired communication network, and outputs the packet information received from the wired communication network to the information processing unit 28. The wireless circuit 26 wirelessly transmits the packet information output from the information processing unit 26 and outputs the packet information received by the wireless signal to the information processing unit 28.

  The information processing unit 28 is configured by an arithmetic processing device such as a processor. The information processing unit 28 executes the program stored in the storage unit 30, and the upstream packet acquisition unit 42, the beacon generation unit 32, the downstream packet generation unit 36, the acknowledge packet generation unit 38, the wired communication packet generation / acquisition unit 40, A channel control unit 46 and a communication status detection unit 45 are configured. In addition, the information processing unit 28 executes a program stored in the storage unit 30 and executes processing for transmitting and receiving packet information.

  The uplink packet acquisition unit 42 constitutes a reception unit that receives uplink packet information together with the radio circuit 26. That is, the upstream packet acquisition unit 42 acquires the upstream packet information received by the wireless circuit 26 and output to the information processing unit 28. Further, the uplink packet acquisition unit 42 includes an address extraction unit 44 that extracts the address of the transmission source of the uplink packet information.

  The beacon generator 32 and the wireless circuit 26 constitute a beacon transmitter that transmits a beacon. That is, the beacon generator 32 generates a beacon and outputs it to the radio circuit 26. The radio circuit 26 transmits a beacon. The beacon generation unit 32 includes an information addition unit 34 that includes additional information such as acknowledge information and downlink information in the beacon.

  The downlink packet generator 36 and the radio circuit 26 constitute a downlink packet transmitter that transmits downlink packet information. That is, the downlink packet generator 36 generates downlink packet information and outputs it to the radio circuit 26. The radio circuit 26 transmits downlink packet information.

  The acknowledge packet generator 38 and the radio circuit 26 constitute an acknowledge packet transmitter that transmits acknowledge packet information. That is, the acknowledge packet generator 38 generates acknowledge packet information and outputs it to the radio circuit 26. The radio circuit 26 transmits acknowledge packet information.

  The wired communication packet generation / acquisition unit 40 acquires packet information output from the wired communication interface 24. Further, the wired communication packet generation / acquisition unit 40 generates packet information to be transmitted to the wired communication network and outputs the packet information to the wired communication interface 24. The channel control unit 46 switches the frequency channel of packet information transmitted and received by the radio circuit 26. The communication status detection unit 45 detects the communication status based on packet information, interference waves, and the like received by the radio circuit 26 and output from the radio circuit 26.

(5) Hardware of Terminal Device FIG. 11 shows an example of hardware of the terminal device 14. The terminal device 14 includes a wireless circuit 50, an information processing unit 52, a storage unit 48, and a wired communication interface 64. The radio circuit 50 wirelessly transmits the packet information output from the information processing unit 52, and outputs the packet information received by the radio signal to the information processing unit 52.

  The information processing unit 52 is configured by an arithmetic processing device such as a processor. The information processing unit 52 executes the program stored in the storage unit 48 and performs a beacon acquisition unit 54, a downlink packet acquisition unit 58, an uplink packet generation unit 56, a time zone determination unit 60, a power supply control unit 62, and a channel control unit 64. Configure. In addition, the information processing unit 52 executes a program stored in the storage unit 48 and executes processing for transmitting and receiving packet information.

  The beacon acquisition unit 54 constitutes a beacon receiving unit that receives a beacon together with the radio circuit 50. That is, the beacon acquisition unit 54 acquires a beacon received by the wireless circuit 50 and output to the information processing unit 52.

  The downlink packet acquisition unit 58 and the radio circuit 50 constitute a downlink packet reception unit that receives downlink packet information. That is, the downlink packet acquisition unit 58 acquires downlink packet information received by the wireless circuit 50 and output to the information processing unit 52.

  The uplink packet generator 56 and the radio circuit 50 constitute a packet transmitter that transmits uplink packet information. That is, the uplink packet generator 56 generates uplink packet information and outputs the uplink packet information to the radio circuit 50. The radio circuit 50 transmits uplink packet information.

  The time zone determination unit 60 recognizes the downlink time zone and the uplink time zone based on the timing information included in the beacon acquired by the beacon acquisition unit 54. The information processing unit 52 executes processing for transmitting and receiving packet information according to these time zones. The power supply control unit 62 controls on / off of the power supply supplied to the wireless circuit 50. The channel control unit 64 switches the frequency channel of packet information transmitted and received by the radio circuit 50.

  The information processing unit 52 may be connected to a wired communication network such as the Internet by a wired communication interface 64. In this case, the wired communication interface 64 transmits the packet information output from the information processing unit 52 to the wired communication network, and outputs the packet information received from the wired communication network to the information processing unit 52. Note that if it is not necessary to connect the terminal device 14 to a wired communication network, the terminal device 14 may not include the wired communication interface 64.

10 wired communication network, 12 base station, 14 terminal device, 16, 16-1 to 16-3 beacon, 18, 18-1 to 18-3 upstream packet information, 20, 20-1, 20-3 downstream packet information, 22-1, 22-3 Acknowledgment packet information, 24, 64 Wired communication interface, 26, 50 Wireless circuit, 28, 52 Information processing unit, 30, 48 Storage unit, 32 Beacon generation unit, 34 Information addition unit, 36 Downstream packet Generation unit, 38 Acknowledgment packet generation unit, 40 Wired communication packet generation / acquisition unit, 42 Uplink packet acquisition unit, 45 Communication status detection unit, 46, 64 Channel control unit, 54 Beacon acquisition unit, 56 Uplink packet generation unit, 58 Downlink Packet generation unit, 60 time zone determination unit, 62 power supply control unit.

Claims (10)

A beacon transmitter that repeatedly transmits a beacon that causes the terminal device to recognize the operation timing; and
A receiving unit for receiving packet information transmitted from the terminal device in response to the beacon;
An extraction unit for extracting terminal identification information included in the packet information;
An information adding unit that includes acknowledgment information for the terminal device to which the terminal identification information is assigned, in the beacon transmitted after the packet information is received;
A base station for packet communication, comprising: In the packet communication base station according to claim 1,
The receiving unit receives the packet information transmitted from each of the plurality of terminal devices in response to the beacon,
The extraction unit extracts the terminal identification information included in each packet information,
The base station for packet communication, wherein the information adding unit includes acknowledge information corresponding to each terminal identification information in the beacon. In the packet communication base station according to claim 2,
The information adding unit includes, in one beacon, acknowledgment information for the terminal identification information up to a predetermined upper limit number among the plurality of terminal identification information,
The packet communication base station is:
An acknowledge packet generation unit that generates acknowledge packet information for the terminal device corresponding to the remaining terminal identification information that did not include acknowledge information in the beacon;
A packet communication base station, comprising: an acknowledge packet transmitter configured to transmit the acknowledge packet information at a timing different from a transmission timing of the beacon. In the packet communication base station according to claim 3,
One transmission cycle for the beacon includes a downlink time zone in which the packet communication base station transmits information, and an uplink time zone in which the packet communication base station receives information,
The packet communication base station, wherein the acknowledge packet transmitting unit transmits the acknowledge packet information in a time zone within the downlink time zone and after the beacon is transmitted. In the base station for packet communication according to any one of claims 1 to 3,
The beacon includes timing information that defines a downlink time zone in which the packet communication base station transmits information and an uplink time zone in which the packet communication base station receives information. Packet communication base station. In the packet communication base station according to any one of claims 1 to 5,
The beacon is downlink information, and includes packet communication base station that indicates timing at which the packet communication base station transmits downlink packet information destined for the terminal device. . In the base station for packet communication according to any one of claims 1 to 6,
A communication status detection unit that detects a communication status for one transmission cycle of the beacon,
The base station for packet communication, wherein the beacon transmission unit transmits the beacon in a transmission cycle after the transmission cycle under a transmission condition according to the communication status. In the wireless terminal device that includes the terminal device and performs wireless communication with the packet communication base station according to claim 5,
A beacon receiving unit for receiving the beacon;
Based on the timing information included in the beacon, a time zone determination unit for obtaining the uplink time zone,
A packet transmitter for transmitting the packet information in the uplink time zone;
A wireless terminal device comprising: In the wireless terminal device including the terminal device and performing wireless communication with the packet communication base station according to claim 6,
A beacon receiving unit for receiving the beacon;
A downlink packet receiving unit that receives the downlink packet information at a timing based on the downlink information included in the beacon;
A power control unit that turns off power of a circuit included in the terminal device from when the beacon is received until reception of the downlink packet information is started,
A wireless terminal device comprising: Including the terminal device;
The beacon transmitting unit transmits a plurality of the beacons having different frequencies within one transmission cycle,
In the radio | wireless terminal apparatus which performs radio | wireless communication between the base stations for packet communication of any one of Claim 1 to 7 in which the said receiving part receives the said several packet information from which a frequency differs,
A beacon receiving unit for receiving the beacon;
A packet transmission unit for transmitting the packet information,
When the beacon receiving unit does not receive the beacon over a predetermined number of transmission cycles, the beacon receiving unit changes the reception frequency of the beacon, and the packet transmitting unit A radio terminal apparatus characterized by changing a transmission frequency.

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