ES2349432T3 - COMMUNICATIONS DEVICE AND COEXISTENCE METHOD TO ALLOW THE COEXISTENCE OF COMMUNICATIONS SYSTEMS. - Google Patents

Abstract

Communications apparatus (111) belonging to one or more domestic communications systems (110, 130) that performs communications within a limited region or an access communications system (120) that connects the limited region with an extended area network , the home communications systems and / or the coexisting access communications system in the same time division communications medium, the apparatus comprising: a power reference point extraction section (203) for extracting a point of reference of a commercial power supply in a power line characterized by: a TDM coexistence control section (205) to transmit / receive a coexistence signal in synchronization with the reference point to detect the coexistence signal, and perform division of time of a TDM cycle with another communication system based on the detected coexistence signal; and a transmission time determination section (202) for synchronizing, according to a result of the time division of the TDM cycle, the transmission time of a reference signal with the reference point extracted by the point extraction section Power reference.

Description

Field of the Invention

The present invention refers to a communications apparatus and a method of coexistence to allow the coexistence of communication systems. More particularly, the present invention refers to a technique for

10 allow the coexistence of two communications systems that use the same communications media and have different communication schemes (data communications are performed while maintaining the AV-QoS [Audio and Video Quality Services] required for communication transmission video and audio), a communications device included in each of the systems

15 of communications, and a method of coexistence executed by the communications apparatus. Background of the invention

Power line communications technology is a means of communication for connecting a personal computer (PC) in a home to a network device, such as a broadband router or similar, so that the computer has access to Internet. In power line communications technology, since an existing power line is used as a means of communication, no new wiring work is necessary, and high-speed communications can be achieved simply by inserting a plug into a

25 outlet available throughout the house. Therefore, research and development, and demonstration experiments of power line communications technology throughout the world, and in Europe and the US, a large number of line communications projects have already been marketed. electric

30 An example of power line communications is HomePlug Ver. 1.0 (see non-patent document 1), which is a specification created by the HomePlug Powerline Alliance (USA). The specification is intended to be used primarily in applications, such as the Internet, mail and file transfer that is done using computers. HomePlug uses a CSMA / CA technique for media access control over which power line communications modem accesses a power line, and provides service communications

5 minimum which does not guarantee a band to use.

Figure 18 is a diagram illustrating a configuration of a general communications system when accessing the Internet. In Fig. 18, a computer 2501 is connected through an Ethernet 2511, a broadband router 2502, and an Internet access line 2512 2522. It is generally used as a power line.

10 access 2512 ADSL, FTTH or similar. When the place where the access line 2512 arrives at the dwelling is not the room where the computer 2501 is located, it is necessary to extend the Ethernet 2511. Therefore, a power line communications device has been commercialized in the form of an adapter of conversion between communications by power line and Ethernet.

15 Figure 19 illustrates a configuration of a communication system using a conversion adapter. In Figure 19, two conversion adapters 2603 and 2604 between power line and Ethernet communications are connected to power outlets in rooms where a computer 2601 and a broadband router 2602 are installed, respectively, and provide

20 minimum service communications using power line communications through a power line in the house 2614. Therefore, using power line communications, no wiring is required, and high-speed communications can be achieved by simply inserting a plug into an outlet of current available through a home.

25 In Europe (Spain, etc.), a communications modem has been used for the power line that uses, as an Internet access line, an electric line for the power supply of a home. Figure 20 is a diagram illustrating a situation in which the power line communications modem is used. A 2703 communications modem master station for access power line

30 provided in an external transformer is connected to a broadband line through an intermediate voltage power distribution line 2713, and communicates with a domestic modem of communications via access electrical line 2702 through a line of Low voltage power distribution 2712, a distribution board 2715 and a domestic power line 2711. In addition, by connecting the communications modem via access power line 2702 with a computer 2701 via an Ethernet 2704, access to Internet

5 from computer 2701.

Therefore, using the modem of communications by electric access line, Internet access can be provided without introducing a cable or similar in a dwelling. In addition, since the communications modem for access power line 2702 is installed at an arbitrary exit in a dwelling, the degree of freedom

10 installation is greater than that of ADSL, FTTH or similar. Figure 21 is a diagram illustrating an internal configuration of a general power line communications modem that is implemented in an Ethernet bridge. In Figure 21, the power line communications modem comprises an AFE (Analog Input Terminal) 2801, a section of

15 digital modulation 2808, a communications control section 2809 and an Ethernet I / F section 2810. The AFE 2801 includes a BPF (bandpass filter) 2802, an AGC (Automatic Gain Control) 2803, a digital analog conversion section 2804 , an LPF (Low Pass Filter) 2805, a PA (Power Amplifier) 2806, and a digital-analog conversion section 2807. Next, it

20 will describe an operation of the power line communications modem. Assuming that the Ethernet frames are transmitted to a power line, when an Ethernet frame arrives through an Ethernet 2811, the communications control section 2809 is informed of the arrival through an Ethernet I / F section 2810. The section communication control 2809 determines a status

25 of a communications channel and produces frame data to a digital modulation section 2808 with appropriate time. Digital modulation section 2808 performs error correction, addition, coding, framing and the like to modulate frame data in a sequence of transmission data. The D / A conversion section 2807 converts the transmission data sequence of a signal

30 digital to an analog signal. The 2806 Power Amplifier amplifies the analog signal. The 2805 low pass filter cuts signals that are not communications band components of the amplified analog signal and only enters the

Communications band components to the power line. Then, in case of reception of an electric line, the bandpass filter 2802 extracts a signal in a communications band. The AGC 2803 amplifies the extracted signal. The analog-digital conversion section 2804 converts the amplified analog signal into digital data. Digital modulation section 2808 detects frame synchronization, equalization, decoding, error correction and the like with respect to digital data to demodulate digital data and notifies communications control section 2809 of the resulting data as data. of reception. Hereinafter, the reception data is transmitted to a

10 Ethernet frame from the I / F section Ethernet 2810 to Ethernet 2811. Although first-generation technology for high-speed power line communications is intended to apply to minimal service applications, such as mail and Internet access on the Internet, Power line communications for which sockets are provided anywhere in a home (it is

15 say, no new wiring is required) have the potential to allow VoIP and video distribution, which are becoming more digital, to be used anywhere in a home.

However, in the case of VoIP, discomfort occurs because the delay time increases in voice signals. Therefore, a packet 20 whose transmission delay exceeds a predetermined level is discarded. The discarded package leads to loss of audio information. As the frequency of packet discard increases, discontinuity or noise in the audio occurs. On the other hand, in the case of video distribution, a large amount of data needs to be communicated. For example, in the case of high definition video, the amount of data per

25 second is 24 Mbits. Such a large amount of data needs to be transmitted by an apparatus with a delay time within a tolerable range. This quality requirement for the transmission of AV data is called AV-QoS, which is generally defined by an average transmission range, a delay time, fluctuation or the like.

Conventionally, as a technique to simultaneously achieve satisfactory AV-QoS of communications by power line and communications by minimum service electric line, a method of access control to the hybrid medium of TDMA (Multiple Time Division Access) and CSMA has been proposed (Multiple Access by Carrier Detection). Figure 22 illustrates an example of the conventional hybrid media access control method.

In Figure 22, the power line communications system designed

5 to satisfy AV-QoS consists of a terminal that has a main function (master terminal) and one or more terminals that have a slave function (slave terminals). The master terminal transmits a beacon 1201 for a predetermined time. The default time is known as the beacon cycle. As the beacon cycle increases, the data delay can be suppressed by

10 smaller level, but decreases the amount of data transmitted by a packet, such that the proportion of packet factor increases, such as header information and the like, which results in a decrease in transmission efficiency. In general, the beacon cycle is set at approximately 10 msec to approximately 100 msec in view of a delay and efficiency requirement

15 transmission of a transmission signal. In addition, in the beacon, the time regions in which communication is allowed for the respective terminals are described. In the example of Figure 22, terminals No. 1 to 3 are allowed for the respective predetermined times. The master terminal also assigns a period of CSMA, after TDMA in which the transmission is controlled with a frequency

20 default. During this period, a terminal that has a transmission signal acquires a transmission right that uses a predetermined algorithm to transmit data. Therefore, the period is appropriate for the transmission of conventional Internet data, such as mail and access to the Web, in which a predetermined amount of data is not generated with a predetermined frequency. Without

However, once the data transmission has begun, the data communication continues as a burst. By separating the TDMA region in this way, it is possible to avoid local interruption of data transmission in the TDMA region. Next, a coexistence control for communications will be described

30 per power line. As described above, several forms of communications by a home's power line to an access network have been considered, and several have been developed

types of power line communications techniques, but currently there is no unified scheme of power line communications. However, the interior power lines are all connected together in a distribution board, and are also connected to an external power line. Therefore, if 5 modems of communications are used per power line for different schemes in the same house and outside the house (near the house), it is likely that a communications signal from one modem will reach other modems. A power line communications modem for one scheme cannot demodulate a signal from another scheme that transmits a power line communications modem for

Another scheme in a communications channel, that is, the signal of the other scheme is only noise. Therefore, if two different communication schemes are performed simultaneously, the two schemes will interfere with each other, so that neither of the two schemes will achieve communication, resulting in a significant decrease in the communication speed, or Similary.

15 As a method to avoid this problem, the creation of a unified standard scheme for power line communications is considered. However, the time and costs required are very high to create a new standard, so a new standard will not be obtained in the near future. To avoid this, for example, patent document 1 proposes a method

20 to control the transmission of control data of each power line modem when there is a plurality of power line modems with different data communication schemes on the same power line. Figure 23 is a diagram to explain this conventional technique. In Figure 23, for example, it is assumed that a selector 61 provides in a

25 management processor 6 selects power line modems 4a to 4m that use a scheme B as power line modems compatible with the transmission. In this case, a message generator 62 generates a transmission-compatible message that indicates the transmission permission to power line modems 4a to 4m using scheme B, and a message that does not allow

30 transmission indicating the prohibition of transmission to power line modems 3a to 3m using a scheme A. Then, a power line modem 3n using scheme A transmits the transmission prohibition message to power line modems 3rd to 3m using scheme A and a power line modem 4n that uses scheme B transmits the transmission permission message to power line modems 4a to 4m using scheme B.

Figure 24 illustrates an operation in which two domestic systems

5 coexist on the same power line by way of time division using the communication system of Figure 23. In Figure 24, the management processor 6 produces a coexistence signal 1401 that allows a domestic communication system 1 to perform transmission and a coexistence signal 1402 that allows a domestic communications system 2 to perform the

10 transmission By periodically repeating the operation using TDM, equal time slots are assigned for the domestic communications system 1 and the domestic communications system 2 without collision. Patent Document 1: Japanese Patent Open for Public Inspection No. 2002-368831 Non-Patent Document 1: Yu-Ju Lin, “Comparative Performance Study of

15 Wireless Networks and Power Line ”, IEEE Communication Magazine, April, 2003, pp. 54-63. Patent Document 2: US Patent Publication No. 2004070912 Disclosure of the Invention Problems to be solved by the invention

20 However, in the conventional system described above, AV-QoS cannot be secured between a plurality of communication systems. Specifically, a communications system that transmits coexistence signals 1401 and 1402 is different from communication that tries to secure AV-QoS in a home. When different communications systems transmit a coexistence signal, the

25 clocks of the communication systems are not synchronized with each other, therefore, the beacon 1201 of the domestic communications system that should ensure the AV-QoS has a different phase from that of the coexistence signal, so that the phase difference increases over time. Therefore, as illustrated in Figure 24, even if the beacon 1201 is transmitted

30 in a first time slot of the domestic communication system 1 during a coexistence cycle immediately after a given coexistence signal, a beacon is then moved into a slot of the domestic communication system 1 during a coexistence cycle after a period of time. of some cycles. Therefore, a transmission time of a terminal in the domestic communication system 1 that begins transmission at a time designated by the beacon 1201 is moved to a time slot of another coexisting system of

5 so that both systems collide, and therefore, a coexistence relationship cannot be maintained. In other words, AV-QoS cannot be maintained.

It should be noted that, since an access communications system provides service to a number of homes, the access communications system functions as a matrix of a coexistence control and makes the

10 home communications systems coexist with their time. Therefore, it is relatively simple to achieve QoS in the access service. In addition, even if a home communications system performs access control using minimum service CSMA, it is possible to easily control the transmission according to an instruction of an existence control section of its terminal.

Therefore, an object of the present invention is to provide a communications apparatus and a method of coexistence in which co-existence can be achieved and to satisfy the AV-QoS in a plurality of different communication systems, in particular, in a system of communications in which it is difficult to determine the presence or absence of a communications signal

20 using only a carrier detector mechanism (for example, power line communications). Solution to the problems

The present invention is directed to a communication apparatus and a method of assigning a transmission band to guarantee QoS based on a reference signal 25, the communication apparatus belongs to one or more domestic communication systems that performs communications within a limited region

or an access communications system that connects the limited region to an extended area network, the home communications system and / or the access communications system coexist in the same communications medium by

30 time division. To achieve the object, the communication apparatus of the present invention comprises a power reference point extraction section for extracting

a reference point of a commercial power supply in a power line, a TDM coexistence control section to transmit / receive a coexistence signal in synchronization with the reference point to control coexistence with another communications division division system. time, and a

5 section of transmission time determination to determine the transmission time of the reference signal in synchronization with the reference point.

Preferably, the power reference point extraction section defines a zero crossing point of the commercial power supply as a reference point, or defines, as a reference point, a point that is phase shifted.

10 for a 60 degree integral multiple of the zero crossing point of the commercial power supply. Usually, the reference signal is a beacon. Effect of the invention

According to the present invention, a band setting method can be used simultaneously to notify the transmission / reception times that

15 occupy and can use the terminals, using a beacon, at once, and a method to make a plurality of communication systems having different communication methods coexist by time division. Brief description of the drawings [FIG. 1] Figure 1 is a diagram schematically illustrating a

20 configuration of a communication system employing a communication apparatus according to a first embodiment of the present invention. [FIG. 2A] Figure 2A is a diagram illustrating a detailed exemplary configuration of a master station 111 of a home system of a home communication system 110.

25 [FIG. 2B] Figure 2B is a diagram illustrating a detailed exemplary configuration of a slave station 112 of a home system of a home communication system 110. [FIG. 2C] Figure 2C is a diagram illustrating a detailed exemplary configuration of a slave station 122 of an access system of a system of

30 access communications 120, and a master station 131 of a home system and a slave station 132 of a home system of a home communication system 130.

[FIG. 3] Figure 3 is a time diagram illustrating operations of a power reference point extraction section 203 and a coexistence signal transmission / reception section 204. [FIG. 4] Figure 4 is a diagram illustrating the time of each signal where

5 uses a zero crossing point as a reference point. [FIG. 5] Figure 5 is a time diagram describing a coexistence process performed by the communication system of the first embodiment. [FIG. 6A] Figure 6A is a flow chart describing an operation of a coexistence process in a stationary state of a master station 111 of the

10 domestic system. [FIG. 6B] Figure 6B is a flow chart describing an operation of a process of measuring a TDM slot for coexistence coexistence and a process of transmitting a beacon in the steady state of the master station 111 of the domestic system.

15 [FIG. 7] Figure 7 is a flowchart describing an operation of a coexistence process in a steady state of a slave station 122 of the access system, the master station 131 of the home system and the slave station 132 of the home system. [FIG. 8] Figure 8 is a time diagram describing another process of

20 coexistence performed by the communication system of the first embodiment. [FIG. 9] Figure 9 is a time diagram describing another coexistence process performed by the communication system of the first embodiment. [FIG. 10] Figure 10 is a time diagram describing another coexistence process performed by the communication system of the first embodiment.

25 [FIG. 11] Figure 11 is a diagram illustrating an exemplary format of a coexistence signal. [FIG. 12] Figure 12 is a diagram describing a conventional problem corresponding to a second embodiment of the present invention. [FIG. 13] Figure 13 is a diagram describing the conventional problem

30 corresponding to the second embodiment of the present invention. [FIG. 14] Figure 14 is a diagram describing the conventional problem corresponding to the second embodiment of the present invention.

[FIG. 15] Figure 15 is a diagram schematically illustrating a configuration of a communication system employing a communication apparatus according to the second embodiment of the present invention. [FIG. 16] Figure 16 is a diagram illustrating a coexistence process

5 exemplary made by the communication system according to the second embodiment of the present invention. [FIG. 17] Figure 17 is a diagram illustrating an exemplary coexistence process performed by the communications system according to the second embodiment of the present invention.

10 [FIG. 18] Figure 18 is a diagram illustrating a conventional configuration of a general communications system that accesses the Internet from a home. [FIG. 19] Figure 19 is a diagram illustrating a conventional configuration of the general communications system that accesses the Internet from a home. [FIG. 20] Figure 20 is a diagram illustrating a conventional configuration

15 of the general communications system that accesses the Internet from a home. [FIG. 21] Figure 21 is a diagram illustrating an internal configuration of a general power line communications modem that is implemented as a bridge with respect to Ethernet. [FIG. 22] Figure 22 is a diagram illustrating the time of a method of

20 communications per conventional power line that performs communications while maintaining the AV-QoS. [FIG. 23] Figure 23 is a diagram illustrating an exemplary configuration of a conventional communications system that causes a plurality of modems to coexist per power line.

25 [FIG. 24] Figure 24 is a time diagram illustrating a coexistence process performed by the conventional communications system of Figure

23. Preferred embodiment of the invention Embodiments of the present invention will be described below with

30 reference to the attached drawings. Note that the following embodiments will be described assuming that a communications medium is a power line,

although the communications medium may be radio waves or a wired medium other than power lines (First realization)

In a first embodiment, an example will be described in which three systems

5 of communications coexist using Time Division Multiplexing (TDM). Figure 1 is a schematic diagram illustrating a configuration of a communication system employing a communication apparatus according to the first embodiment of the present invention. In the first embodiment, there are three communication systems, that is, domestic communication systems 110 and

10 130 and an access communication system 120. Note that the configuration of the communication system of Figure 1 is offered for illustrative purposes only. The domestic communications system 110 and the domestic communications system 130 may be in the same dwelling and there may be three or more domestic communications systems.

15 The domestic communications system 110 is a domestic communications system that uses a power line 113 provided in a dwelling and is composed of a master station of the domestic system 111 which controls the coexistence of the domestic communications system 110 and the communications system of access 120, and a slave station 112 of the domestic system

20 other than master station 111 of the home system. The master station 111 of the home system is a communication apparatus that has a function of receiving a coexistence signal that is transmitted by a station belonging to an access communication system 120, and controls the slave station 112 of the home system. In general, only one station is provided

25 master 111 of the domestic system in a dwelling, and it can be determined in a specific and fixed way or it can be determined dynamically or changed during an operation. The slave station 112 of the home system is a communication apparatus that is operated in a control of the master station 111 of the home system, and one or more slave stations 112 of the system are provided

30 domestic in a domestic communications system 110. The domestic communications system 130 is a power line communications system that uses an electric line 133 provided in a

housing and is composed of a master station 131 of the domestic system that controls the coexistence of the domestic communications system 130 and the access communications system 120 and a slave station 132 of the domestic system that is not the master station 131 of the domestic system. Master Station 131 of

The home system and the slave station 132 of the home system have the same configuration, function and role as those of the master station 111 of the home system and the slave station 112 of the home communication system 110, respectively.

The access communications system 120 is a system of

10 communications per power line using the domestic power line 113, a low-voltage power distribution line 124 provided from the housing to a pole-mounted transformer 126 provided in a service pole 123 and a power distribution line of intermediate voltage 125 from the pole-mounted transformer 126 to the electrical power substation (not shown).

15 Of the communication devices belonging to the access communications system 120 there is a master station 121 of the access system and a domestic device of the access system (hereinafter referred to as the slave station of the access system) 122 provided in the housing , which is located within a range that causes interference with the domestic communications system 110.

20 The master station 121 of the access system may be provided as a communications apparatus separate from the pole transformer 126 as illustrated in Figure 1, or it may be incorporated into the pole transformer 126. Alternatively, in view of, for example, , the case where a power line is buried, the master station 121 of the access system may be incorporated in an apparatus

25, other than the pole transformer 126. It should be noted that, for example, the slave station 122 of the access system can also be provided on the low voltage power distribution line 124 outside the dwelling, and a function can be assigned of communication from the domestic communication system 110 to the slave station 122 of the access system.

30 Although not illustrated in Figure 1, the master station 111 of the home system and the slave station 122 of the access system are connected via Ethernet, wireless LAN or the like, or alternatively, for example, master station 111 of the home system and the slave station 122 of the access system are provided in a single device, thus allowing intercommunication between the domestic communication system 110 and the access communication system

120.

5 In the first embodiment, communication systems 110 and 130 can each have a function capable of using a frequency band of, for example, 2 MHz to 30 MHz. The frequency band is used to transmit and receive a signal from coexistence for the coexistence of communication systems 110 to 130 without interference with each other, and to carry out data communications in each

10 communications system. The access communication system 120 can be used, with priority, all or part of the time for which the frequency band is used. The home communication systems 110 and 130 detect a time that is used by the access communication system 120, using a coexistence signal (described below) and shares a time that is not

15 used by the access communications system 120, by time division using the coexistence signal (described below). When the access communications system 120 is not present, home communications systems 110 and 130 can use a time, which is divided into two. Next, with reference to Figures 2A to 2C and 3, it will be described in

20 details a configuration and transmission / reception of a coexistence signal of each station, where the domestic communications system 110 of Figure 1 is a communications system that guarantees its QoS using a function of producing a periodic reference signal, and the access communications system 120 and the neighboring domestic communications system 130 are not

25 compatible with the QoS. Note that, in embodiments below, examples will be described in which the periodic reference signal produced by the domestic communication system 110 is a beacon. Figure 2A is a diagram illustrating a detailed exemplary configuration of a master station 111 of a home system of a system

30 domestic communications 110. The master station 111 of a domestic system comprises a beacon transmission time determination section 202, a power reference point extraction section 203, a coexistence signal transmission / reception section 204, a TDM coexistence control section and a modem signal transmission / reception section

206. Although the case will be described where a master station that controls a coexistence signal also has a function of transmitting a QoS beacon in this embodiment, the beacon function may have another device other than the master station that controls the signal. of coexistence

Figure 2B is a diagram illustrating a detailed exemplary configuration of a slave station 112 of a home system of a home communication system 110. Slave station 112 of a home system

10 comprises a data transmission time determination section 207 and a modem signal transmission / reception section 206. Figure 2C is a diagram illustrating detailed exemplary configurations of a slave station 122 of an access system of a system of access communications 120, and a master station 131 of a home system

15 and a slave station 132 of a domestic system of a domestic communication system 130. Each of these stations comprises a power reference point extraction section 203, a coexistence signal transmission / reception section 204, a section of coexistence control by TDM 205 and a signal transmission / reception section of

20 modem 206. Figure 3 is a time diagram describing operations of a power reference point extraction section 203 and a coexistence signal transmission / reception section 204. In the example of Figure 3, described a three-phase alternating power supply, which is mainly used in

25 Europe. The present invention also has an effect with respect to a three-phase three-phase system (Japan, United States and Asia) and power lines in all other countries. The three alternating power supplies 301 to 303 illustrated in Figure 3 have phases that move 60 degrees relative to each other. System

Multiphasic power is divided and distributed in cables that have respective phases in a dwelling, so that an electronic device can detect only the power of one of the phases. Therefore, there is a phase difference between electronic devices connected to cables that have different phases, even if the zero crossing point is selected as the reference point. Consequently, each electronic device uses a zero crossing point detected by itself as a reference point and selects a reference point every 60 degrees

5 from that reference point, thus making it possible for the reference point to coincide with those of all electronic devices.

This situation is illustrated in Figure 4. Part (a) of Figure 4 indicates an internal signal of the power reference point extraction section 203 of Figure 2, where a pulse is generated by zero crossing point of an alternating signal.

10 Part (b) of Figure 4 indicates an output signal of the power reference point extraction section 203, where a pulse is generated every 60 degrees using the internal signal of part (a) as a reference.

The coexistence signal transmission / reception section 204 notifies other communication systems of the presence of a communication system 15 to which the coexistence signal transmission / reception section 204 belongs, and is also notified of the presence of others. communication systems, where time slots that are used in common by coexisting communication systems are defined using reference points. Here, an example will be described in which three communication systems including a communication system

20 access communications use a TDM coexistence signal to achieve coexistence. Note that the coexistence signal can be an FDM scheme or a hybrid FDM and TDM scheme.

A coexistence signal 305 is arranged using a synchronization point as a reference and a plurality of slots are set, according to times 25 of the synchronization point. Each communication system, when using a power line, transmits a specific signal in a corresponding slot. The specific signal can be, for example, an OFDM signal represented by an existing function. A communications system that knows the function can detect the specific signal and know the use of a slot. Each of the 30 communication systems that coexist tries to detect the coexistence signal 305 at each reference point. When the coexistence signal 305 cannot be detected, the communication system determines that there is no other communication system

coexisting, and transmits a coexistence signal with time from a reference point each predetermined coexistence cycle. On the other hand, when the coexistence signal has been detected, the communications system determines a coexistence cycle, and a TDM cycle and an ordinal position (TDM slot) thereof.

5 The TDM 205 coexistence control section is notified about the information of the detected coexistence signal 305.

When the presence of a single communication system has been detected in the coexistence signal 305, the communication system can take up all the time in a TDM cycle (TDM slot) ((c) in Figure 4). When has

10 Having detected the presence of two communication systems in the coexistence signal 305, the three communication systems can share the time of a TDM cycle, which is divided into three, for example ((c) of Figure 4). It should be noted that, if it is previously defined in the configurations that ½ of the total time is used by the access communications system, for example, the vision / assignment is made

15 according to the settings. When the TDM 205 coexistence control section has determined a TDM slot that is used by a communications system to which the TDM 205 coexistence control section belongs, the modem signal transmission / reception section 206 transmits a modem signal only to

20 the TDM slot, and performs reception only in the TDM slot. Thus, the beacon transmission time determination section 202 of the home system master station 111 can know in advance the information for synchronization with other coexisting communication systems and the number of communication systems to coexist, more

25 specifically, transmission time of a communication system to which the master station of the domestic system 111 belongs, of the extraction section of the power reference puno 203 and the co-existence control section of TDM 205. It should be noted that, given that the TDM cycle time is synchronized

30 with the feeding system, by synchronizing the beacon transmission time with the feeding system based on the information of the power reference point extraction section 203, the transmission time allocation of the

Figure 5 can be determined previously and easily fixed on a beacon. In Figure 5, since the transmission time of the communication system to which the master station 111 of the home system belongs can be previously set with respect to a synchronized clock, it is possible to notify about the time 5 with which a system slave station of communications to which the master station 111 of the home system belongs carries out the transmission / reception in a plurality of TDM slot with time division in a beacon 501. Therefore, the slave station can perform the transmission / reception in a slot of TDM 502 fixed in the communications system to which the master station 111 of the

10 home system simply by transmitting / receiving at a time designated by your master station. Here, a flow of operations of a coexistence process in a fixed state of the master station 111 of the home system is illustrated in Figure 6A, and a process of counting the number of TDM slots for coexistence and transmission of

A beacon is illustrated in Figure 6B. As used herein, the fixed state refers to a normal operating state that excludes states during the activation of a station, abnormal operations and the like. Figure 6A does not illustrate the data communication, control of devices or the like in the fixed station, which refer to the coexistence process.

In Figure 6A, the master station 111 of the home system, upon detecting the zero crossing point (step S601), determines whether it is time to transmit a coexistence signal (step S602). When it is not time to transmit a coexistence signal, the master station 111 of the home system proceeds to detect a zero crossing point. When it is time to transmit a signal from

25 coexistence, the master station 111 of the home system transmits a coexistence signal (step S603). In Figure 6B, the master station 111 of the home system, upon detecting a zero crossing point (step S604), updates the zero crossing point (step S605) before measuring a time in a time slot with reference to Point of

30 zero crossing (step S606). On the other hand, when the zero crossing point is not detected, the master station 111 of the home system does not update the zero crossing point and goes on to measure a time in a time slot with reference to a point

zero crossing previously detected (step S606). The operation described above is repeated until a beacon transmission time (step S607). When the beacon transmission time arrives, the master station 111 of the home system determines if a TDM slot at that time is a TDM slot that the communication system to which the master station 111 of the home system belongs has permission to use (step S608). By determining that the TDM slot at that time is a TDM slot of the communication system to which the master station 111 of the home system belongs, the master station 111 of the home system transmits a beacon (step S609). When determining that the TDM slot in

10 that moment is not a TDM slot of the communication system to which the master station 111 of the home system belongs, the transmission of a beacon is not performed and steps S604 to S606 described above are repeated.

In addition, an operational flow related to a coexistence process in a fixed state of the slave station 122 of the access system, the master station 131 15 of the domestic system and the slave station 132 of the domestic system is indicated in Figure 7. The station slave 122 of the access system, the master station 131 of the domestic system and the slave station 132 of the domestic system, upon detecting a zero crossing point (step S701), determines whether it is not time to transmit a coexistence signal (step S702 ). When it is not time to transmit a signal of coexistence, the slave station 122 of the access system, the master station 131 of the domestic system and the slave station 132 of the domestic system continue to detect the zero crossing point. When it is time to transmit a coexistence signal, the slave station 122 of the access system, the master station 131 of the home system and the slave station 132 of the home system

25 transmit a coexistence signal (step S703). Next, a specific example in which a coexistence signal is extended will be described. Figure 8 is a diagram illustrating the time of coexistence signals, TDM slots, beacons and data slots when the access communications system

30 120 and the domestic communication systems 110 and 130 coexist by time division multiplexing. In Figure 8, five TDM slots (Slot D to S 1 to 4) are fixed in a TDM cycle. Slots S 3 and 4 are occupied slots

by the access communication system 120. Slots S 1 and 2 are slots that continue to be used by any of the access communication system 120 and the home communication systems 110 and 130 by means of declaration means. Slot D is a slot that can be used alternatively for a maximum of three communication systems that declare using slot D in a coexistence signal. Slot D is a TDM slot that is introduced in a way that handles data dynamically and efficiently, where this data is generated irregularly as a burst. Note that, during a period of time in which only one communications system declares the use of the

10 slot D, slot D has the same definition as slot S. Figure 9 is a diagram illustrating the time of coexistence signals, TDM slots, beacons and data slots when the access communications system 120 and the 110 and 130 home communications systems coexist by frequency division multiplexing. In figure 9, together with the control of

In co-existence by TDM described above, it is defined that the access communication system 120 uses a #X channel with priority, and the communication systems 110 and 130 use a #Y channel. In this case, if access communication system 120 is not present, channel #X can also be used by home communication systems 110 and 130 (see Figure 10).

Figure 11 is a diagram illustrating an exemplary format of a coexistence signal that is extended to be compatible with the coexistence method described above. The coexistence signal of Figure 11 is composed of slots A, H1 to H4, JL, JH, Ba to Bc and X defined by time division and channels #X and #Y defined by frequency division. Slots H1 to H4 correspond to slots S 1 to 4.

25 Slots JL and JH are used when a communication system that wishes to use a slot S again issues a join request with respect to a communication system that has already used a slot S. For example, when a communication system A is used in all slots S 1 to 4, slots H1 to H4 of the coexistence signal have already been used. Therefore, another system of

30 communications B that subsequently wishes to coexist transmits a signal in slots JL and JH, but not in slots H1 to H4, thereby requesting the release of a slot with respect to communications system A. Slot JL and slot JH They are different in priority. Communication system A compares the priority of a requested slot with its priority, to determine for itself how many slots S should be released. Slots Ba to Bc are slots to control a slot D. Slot X is a slot that requests resynchronization of cycles of

5 coexistence signals between communication systems. The method of controlling the slots Ba to Bc and X are not subjects of the present invention and will not be described.

As described above, the communications system and the coexistence method of the first embodiment of the present invention employing a communications apparatus can simultaneously employ a method of

10 band configuration for the notification of transmission / reception times that are occupied and can be used by terminals, using a beacon, at once, and a method of making a plurality of communication systems with different communication methods coexist by division of time. (Second embodiment)

A method to make a plurality of communication systems coexist by time division performs a control based on a coexistence signal that each communication system transmits to other communication systems. Therefore, two communication systems can be made between which a signal is not communicated directly coexist and are

20 synchronized with each other through another communication system that intervenes between them. However, there is also a device that works only when used and a device that works all the time, of electronic devices that belong to a domestic communications system. Therefore, when the system

25 communications involved are turned off (OFF), the synchronization relationship between the two communication systems between which a signal is not communicated directly collapses. Therefore, when the communications system involved is turned on (ON) in the following time, the coexistence / synchronization control must be carried out from scratch. In other words, when a

In particular, the communications system is on / off, the synchronization of the entire system may be interrupted.

-22 For example, as illustrated in Figure 12, it is assumed that communication systems 1210 and 1230 are synchronized through a communication system 1220. In this situation, when communication system 1220 is off, the communication systems Communications 1210 and 1230 cannot receive mutually a coexistence signal that is transmitted from one to the other. Therefore, communication systems 1210 and 1230 transmit a coexistence signal with respective separate times. As a result, the coexistence signal transmission times of the two communication systems 1210 and 1230 deviate from each other, according to a difference in precision between clocks of the master stations 10 of the two communication systems 1210 and 1230 (Figure 13 ). Therefore, when the communication system 1220 is switched on again in this situation and synchronizes with a coexistence signal of one of the two communication systems, the communication system 1220 interferes with the other communication system (Figure 14). Therefore, in a second embodiment, a technique that solves the problem described above is described. Fig. 15 is a diagram schematically illustrating a communication system according to the second embodiment of the present invention employing communication devices. The communication system of the second embodiment 20 has the same configuration as that of the communication system of the first embodiment, except that a neighboring domestic communications system 140 is added. The configuration of the communication system of Figure 15 is for illustrative purposes only. Alternatively, the domestic communications system 110 and the domestic communications system 130 may be provided in the same dwelling, or four or more domestic communications systems may be provided. Note that the same parts of those of the first embodiment will not be described. The domestic communications system 140 is a power line communications system that uses a wired power line 133 in a dwelling, and is composed of a master station of the domestic system 141 that controls coexistence with the access communications system 120, and a slave station 142 of the home system that is not the master station of the system

domestic 141. The master station of the domestic system 141 and the slave station 142 of the domestic system have the same configurations, functions and roles as those of the master station of the domestic system 111 and the slave station 112 of the domestic system of the domestic communications system 110 ,

5 respectively.

In this embodiment, the case will be described where three communication systems (i.e., domestic communication systems 110, 130 and 140) already establish a coexistence control relationship according to the procedure described in the first embodiment. In addition, it is assumed that the system of

10 domestic communications 140 and domestic communications system 110 have a relationship that a signal does not communicate with each other, for example, because the two systems are distant from an electric line. This means that, if there is no domestic communications system 130, domestic communications system 130 and domestic communications system 140 do not have a relationship

15 that the two systems should coexist. Initially, using a coexistence signal transmitted by the access communications system 120 as a reference, the domestic communication system 110 synchronizes with the coexistence signal, and transmits a coexistence signal that includes information about it. Then the system of

20 domestic communications 130 synchronizes with this coexistence signal and transmits a coexistence signal that also includes information about it. Finally, the domestic communications system 140 synchronizes with this coexistence signal and transmits a coexistence signal that also includes information about it. In this way, home communications systems 110, 130 and 140 build

25 a coexistence control relationship. This is illustrated in Figure 16. When the domestic communications system 130 is turned off in this situation, the domestic communications systems 110 and 140 cannot mutually receive a coexistence signal transmitted from each other (Figure 17). Therefore, home communications systems 110 and 140 transmit

30 a coexistence signal with respective separate times. However, in the present invention, the home communication systems 110 and 140 go on to transmit a coexistence signal at intervals

presets that synchronize with a common commercial power supply, so transmission times are transmitted. Therefore, even if the domestic communication system 130 is turned on again, the synchronization of the coexistence signal of the domestic communication system 110 and the signal of

5 coexistence of the domestic communications system 140 is maintained, such that the domestic communications system 130 can transmit a coexistence signal with the synchronized time.

As described above, according to the communications system and the coexistence method of the second embodiment of the present invention that

10 employs a communications apparatus, the transmission time of the coexistence signal is synchronized with a commercial power supply so that a coexisting communications system can continue to operate stably. Therefore, the conventional disadvantage that the quality of service is altered every time a coexisting communications system is activated or stopped can be overcome.

15 It should be noted that the above described embodiments can be implemented by having a CPU interpret and execute predetermined program data capable of executing the procedure described above, the program is stored in a storage device (a ROM, a RAM, a hard disk , etc.). In this case, the program data can be stored in the device

20 storage through a recording medium or can be run directly from the recording medium. The recording medium refers to a semiconductor memory, such as a ROM, a RAM, a flash memory or the like; a magnetic disk, such as a flexible disk, a hard disk or the like; an optical disc, such as a CD-ROM, a DVD or BD or the like; a card

25 memory; or similar. The recording medium is a concept that includes a communications medium, such as a telephone line, a transfer line or the like.

The functional blocks of each embodiment, such as the beacon transmission time determination section, the power reference point extraction section 30, the coexistence signal transmission / reception section, the coexistence control section of TDM and the modem signal transmission / reception section and the like can usually

be implemented as an integrated circuit (LSI: LSI is called IC, LSI system, super LSI or ultra LSI, depending on packaging density). Each functional block can be separated mounted on a chip, or a part or all functional blocks can be mounted on a chip. In addition, a party involved in communications and a party

5 involved in the transmission / reception of a coexistence signal in a communications system can be mounted on separate LSI chips. The integrated circuit is not limited to LSI. The integrated circuit can be achieved through a dedicated circuit or a general purpose processor. In addition, a Field Programmable Door Array (FPGA) can be used

10 English) that can be programmed after LSI production or a reconfigurable processor in which the connection or configurations of circuit cells in LSI can be reconfigured. In addition, if an integrated circuit technology that replaces LSI is developed through an advance in semiconductor technology or the emergence of other

15 technologies derived from it, the functional blocks can be packaged using said technology. A biotechnology may be applicable. The home communications apparatus of the present invention may be an adapter that converts a signal interface, such as an Ethernet interface, an IEEE 1394 interface, a USB interface or the like, into an interface for

20 communications per power line, and in that way, can be connected to multimedia devices, such as a personal computer, a DVD recorder, a digital television, a home system server, and the like, which have various types of interface. In this way, a network, a system that transmits digital data, such as multimedia data or the like, can be constructed through a power line such as

25 medium with high speed. As a result, a power line that is provided in homes, offices and the like can be used directly as a network line without introducing a new network cable, such as a conventional wired LAN. Therefore, the present invention is considerably useful in terms of cost and ease of installation.

The functions of the present invention can be incorporated into the multimedia devices described above in the future. In this way, data transfer can be achieved between multimedia devices through a source cable

feeding them. In this case, an adapter, an Ethernet cable, an IEEE 1394 cable, a USB cable and the like are not required, thus simplifying the wiring. In addition, the high-speed power line transmission system of the present invention can be connected through a router to the Internet, or through a hub to a wireless LAN or a conventional wired LAN, thus extending a LAN system in which the high speed power line transmission system of the present invention is used without problems. Communications data transferred through a power line via power line transmission can be intercepted by a device directly

10 connected to the power line, but are free from a wireless LAN listening problem. Therefore, the power line transmission scheme is effective for data protection in terms of security. In addition, data transfer on a power line may be protected by IPSec from an IP protocol, content encryption, other DRM schemes or the like.

15 Compared to communications by power line, the transmission of high-quality AV content on a power line can be achieved using an intellectual property rights protection function using the encryption of efficient content or media described above (an effect of the present invention) and also implementing a QoS function.

20 Industrial application The present invention can be used when a plurality of communication systems, which cannot be interconnected with each other, make communications in a common communication medium without interference with one another or the like, and is applicable to various electrical and similar devices that they have, in

In particular, a modem that uses a power line or radio waves as the communications medium and the communications functions mentioned above.

Claims (7)

 Claims 1. Communications apparatus (111) belonging to one or more domestic communications systems (110, 130) that performs communications within a limited region or an access communications system (120) that connects the 5 limited region with an extended area network, the home communications systems and / or the coexisting access communications system in the same time division communications medium, the apparatus comprising: a power reference point extraction section (203) for extracting a reference point from a commercial power supply in 10 an electric line characterized by: a TDM coexistence control section (205) for transmitting / receiving a coexistence signal in synchronization with the reference point to detect the coexistence signal, and performing time division of a TDM cycle with another communications system based on the coexistence signal 15 detected; and a transmission time determination section (202) for synchronizing, according to a result of the time division of the TDM cycle, the transmission time of a reference signal with the reference point extracted by the point extraction section Power reference. The communication apparatus according to claim 1, wherein the communication apparatus allocates a transmission band to guarantee QoS based on the reference signal. 3. Communications apparatus according to any of claims 1 and 2, wherein the power reference point extraction section (203) defines a 25 zero crossing point of the commercial power supply as a reference point. 4. Communications apparatus according to any of claims 1 and 2, wherein the power reference point extraction section (203) defines, as a reference point, a point that is displaced by an integral multiple of 60 30 degrees from a zero crossing point of the commercial power supply.

5.

Communication apparatus according to any of claims 1 and 2, wherein the reference signal is a beacon.

6.

Method performed by the communications apparatus (111) belonging to one or more domestic communications systems (110, 130) that performs communications within a limited region or an access communications system (120) that connects the limited region to a extended area network, where

5 home communications systems and / or the access communications system coexist in the same time division communications medium, the method comprising the steps of: extract a reference point from a commercial power supply on a power line characterized by: 10 transmit / receive a coexistence signal in synchronization with the reference point to detect the coexistence signal, and perform time division of a TDM cycle with another communication system based on the detected coexistence signal; and synchronize, according to a result of the time division of the TDM cycle, the 15 transmission time of a reference signal with the reference point. 7. Method according to claim 6, wherein the communication apparatus allocates a transmission band to guarantee QoS based on the reference signal. 8. Integrated circuit for use in a communications device (111) that belongs to one or more home communications systems (110, 130) 20 that performs communications within a limited region or an access communications system (120) that connects the limited region to an extended area network, where the home communications systems and / or the access communications system coexist therein Time division communications medium, the integrated circuit comprises circuits that function as: 25 a power reference point extraction section (203) for extracting a reference point from a commercial power supply in a power line; a TDM coexistence control section (205) to transmit / receive a coexistence signal in synchronization with the reference point to detect the coexistence signal, and perform time division of a cycle of 30 TDM with another communication system based on the detected coexistence signal characterized by: a section of transmission time determination (202) to synchronize, according to a result of the time division of the TDM cycle, the transmission time of a reference signal with the reference point extracted by the power reference point extraction section. 5. Integrated circuit according to claim 8, wherein the communication apparatus allocates a transmission band to guarantee QoS based on the reference signal. “16 pages of drawings follow”