JP2008011301A - Power line communication apparatus and start initiation process thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power line communication apparatus capable of properly executing a starting time operation of itself, and to provide a start initiation process thereof. <P>SOLUTION: The power line communication apparatus includes reception processing sections (11, 12, 15 or the like), a coexistence signal detection section (CDCF signal detection section 32), a marker signal detection section (beacon signal detection section 31), a coexistence signal generating section (CDCF signal generating section 34), a marker signal generating section (beacon signal generating section 33), transmission sections (16, 17 or the like), and a control section 20. The control section 20 carries out execution or instructions for: first transmission wherein a CDCF signal and a beacon signal are transmitted without executing window timing commonality; second transmission wherein the two signals above are transmitted while executing the window timing commonality, on the basis of the presence of the CDCF signal, its CDCF window timing, and the presence of the beacon signal; holding of the status quo; and window timing commonality only. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a power line communication device in which a bandwidth window for reserving a system coexisting bandwidth and a communication bandwidth for data communication are alternately allocated at a predetermined cycle, and an operation method at the time of startup.

There are various types of communication devices that use power lines.
For example, there are ASK (Amplitude Shift Keying), FSK (Frequency Shift Keying), PSK (Phase Shift Keying), etc. as modulation schemes, and there are single carrier scheme and OFDM (Orthogonal Frequency Division Multiplexing) scheme as transmission schemes, A spread spectrum method is also used.

However, if these systems are different, they cannot communicate with each other.
For example, even if the same OFDM system is used, if any one of specifications such as occupied bandwidth, subcarrier spacing, subcarrier modulation system, synchronization signal, coding system, access control system, and data format is different, communication is performed with each other. Can not do it. Hereinafter, “different systems” means that such communication specifications are different.

  When devices of different systems that cannot communicate with each other in this way exist in the same home, the transmission signals of both cause a collision and a communication failure occurs. In the worst case, both cannot communicate at all. As power line communication devices become more widespread in the future, it is expected that how to reduce or prevent interference between communication devices of different systems and to make them coexist will be important.

  Regarding coexistence of wireless communication systems of different systems, a technique is known that prepares a signal (beacon signal) that can be transmitted and received by communication apparatuses of different systems and adjusts the communication timing (see, for example, Patent Document 1).

In a general wireless LAN, a beacon signal is used as follows, for example.
The master unit (master station) periodically broadcasts a radio beacon signal (a kind of OFDM-modulated control packet) called a beacon signal. The slave unit (slave station) receives the beacon signal transmitted on all the radio channels, and selects the optimum master unit based on this beacon signal. Next, the slave unit requests authentication from the selected master unit, the master unit determines whether to authenticate the slave unit that wants to connect to its own network, and exchanges management signals with each other if it can be authenticated. Thereafter, the slave unit is handled as an official wireless LAN terminal.

In this way, the beacon signal is used as a radio identification signal of the network managed by the master station and devices connected to the network (hereinafter, the network and the connected devices are also referred to as “systems”) and transmitted from the master station. It is a kind of control signal in the system.
The invention described in Patent Document 1 described above aims at coexistence between different systems by providing detailed control information such as transmission parameters in a beacon signal defined in common between systems.

  On the other hand, in the field of power line communication, a CDCF (commonly distributed coordination function) signal is used as a coexistence control signal (hereinafter referred to as a coexistence signal) that can be recognized by different types of modems in order to allow communication devices (for example, PLC modems) to coexist. It has been studied to formulate a system specification for bandwidth reservation using this (see, for example, Non-Patent Document 1).

In power line communication, it is difficult to unify methods because existing power lines are used, and specifications for coexistence of methods need to be as simple as possible.
Therefore, the CDCF signal uses the OFDM method on the premise of the method used by recent high-speed modems, but the modems cannot exchange detailed information, and the presence of a master station that reserves bandwidth It's just enough to let you know.
JP 2003-258812 A CEPCA Technical Work Group, “CEPCA Technical Specification”, CEPCA Technical Seminar, April 5, 2006, Internet <URL: http://www.cepca.org/about_us/Events/past_events/japan_seminar/CEPCA_SeminarSpecification.pdf>

Patent Document 1 describes that a beacon signal (a kind of beacon signal) that is common between different systems is used for coexistence between different systems, and the presence and usage status of a wireless network can be mutually confirmed by this signal. Has been.
In power line communication, coexistence signals (for example, CDCF signals) have the same function, but the power line communication network is not limited to newly introduced ones, and uses existing equipment, so the coexistence signals have detailed information. However, there is a concern that many devices will not be able to handle it, and power line communication will not spread. Therefore, in the power line communication specification, the coexistence signal is defined as a signal in which the presence / absence of the signal and the timing within the band (band window) dedicated to the signal are important.

Regarding the CDCF signal, the correspondence between the time or frequency area allocated within the band window and its meaning is disclosed in Non-Patent Document 1 described above.
However, each system that can coexist in power line communication has a beacon signal (for example, a beacon signal) for network connection authentication. When a communication device such as a modem is activated, both the coexistence signal and the beacon signal are detected. It is not disclosed in Non-Patent Document 1 whether it is better to detect by such a procedure and perform the initial operation at the time of startup.

  The problem to be solved by the present invention is to provide a power line communication apparatus having a configuration capable of appropriately performing an operation at startup and an operation method at startup.

The power line communication apparatus according to the present invention allocates a coherent signal for bandwidth reservation among a plurality of systems having different modulation methods to a time window that can be assigned to a different time domain for each system, and assigns arbitrary information to a different time domain for each system. A power line communication device in which a possible communication band is allocated alternately and at a periodic timing, and a reception processing unit that receives and processes a signal from a power line communication network, and a reception received by the reception processing unit A coexistence signal detection unit capable of detecting timing of the coexistence signal and its band window from a signal, a beacon signal detection unit capable of detecting the beacon signal from the received signal, a coexistence signal generation unit for generating a coexistence signal, It has a beacon signal generator for generating an identification signal, a transmission processor for processing the signal and transmitting it to the power line communication network, and a controller.
Based on the presence / absence of the coexistence signal detected by the coexistence signal detection unit and the timing of the band window and the presence / absence of the identification signal detected by the beacon signal detection unit, the control unit Execute any one of the operations, that is, the first transmission, the second transmission, the current status maintenance, and the window timing common operation, or the execution instruction to the coexistence signal generation unit, the beacon signal generation unit, and the transmission processing unit. Do.
(1) First transmission:
Generating the coexistence signal and the beacon signal in at least one of the case where the coexistence signal is not detected and the case where the coexistence signal is detected in the band window of a predetermined period but the beacon signal is not detected; Transmit from the transmission processing unit.
(2) Second transmission:
When a plurality of the coexistence signals are detected in the plurality of band windows whose periods are shifted, but the marker signal is not detected, the window timing is determined by performing window timing commonization that aligns the timings of the plurality of band windows. A common coexistence signal and a beacon signal are generated and transmitted from the transmission processing unit.
(3) Current status maintenance:
When the coexistence signal is detected in the band window of a predetermined period and the beacon signal is detected, the window timing is not shared, and the coexistence signal and the beacon signal are not generated and transmitted.
(4) Common window timing:
The operations when the plurality of coexistence signals are detected in the plurality of band windows whose periods are shifted and the beacon signal is detected and the coexistence signal and the beacon signal are not generated and transmitted. .

  The power line communication start-up operation method according to the present invention includes a bandwidth window that can allocate a coexistence signal for bandwidth reservation among a plurality of systems having different modulation schemes to different time domains for each system, and different arbitrary information for each system. This is a power line communication device start-up operation method in which communication bands that can be assigned to the time domain are assigned alternately and at periodic timing.

The start-up operation method according to the first aspect of the present invention includes a coexistence detection step of detecting timing of the coexistence signal and the band window from a received signal in response to an input of a start instruction, and the coexistence signal is detected by the coexistence detection. A label detection step of detecting the label signal from the received signal when detected, and a plurality of the band windows whose periods are shifted in the coexistence detection when the label signal is not detected by the label detection. A first window timing confirmation step for checking whether the detected signal is detected, and when the beacon signal is detected by the beacon detection, the coexistence signal is detected by the plurality of band windows whose periods are shifted by the coexistence detection. A second window timing confirmation step for checking whether or not, a window timing sharing step for aligning the timings of the plurality of band windows, and the coexistence signal and the indicator signal are generated. Including No. a step of generating and a transmission step of transmitting the coexistence signal and the said indicator signal.
Then, one of the following operations is executed based on at least one of the result of the coexistence detection, the result of the marker detection, and the result of the first and second window timing confirmation.
(1A) First transmission:
The coexistence occurs in two cases: a case where the coexistence signal is not detected and a case where the coexistence signal is detected but the indicator signal is not detected and the detection of the plurality of band windows is not confirmed in the first window timing confirmation. A signal and the beacon signal are generated and transmitted.
(2A) Second transmission:
When the sign signal is not detected but the detection of the plurality of band windows is confirmed by the first window timing confirmation, the window timing is shared and the coexistence signal and the sign signal are made common to the window timing. Is generated and transmitted.
(3A) Current status maintenance:
When the beacon signal is detected but the detection of the plurality of coexistence signals is not confirmed in the second window timing confirmation, the window timing sharing, the coexistence signal and the beacon signal are not generated and transmitted.
(4A) Window timing standardization:
This is an operation when generation and transmission of the coexistence signal and the beacon signal are not performed when the beacon signal is detected and the detection of the plurality of coexistence signals is confirmed in the second window timing confirmation.

According to a second aspect of the present invention, a start-up operation method includes a step of detecting a sign from a received signal in response to an input of a start instruction, and a received signal when the sign signal is not detected by the sign detection. A coexistence detection step for detecting the timing of the coexistence signal and the band window; and, when the coexistence signal is detected, the coexistence signal is detected in the plurality of band windows whose periods are shifted. A first window timing check step for checking whether a plurality of coexistence signals are detected in the plurality of band windows whose periods are shifted by the coexistence detection when the indicator signal is detected. A window timing confirmation step, a window timing sharing step for aligning the timings of the plurality of band windows, a signal generation step for generating the coexistence signal and the beacon signal, Transmitting the coexistence signal and the beacon signal, and based on at least one of the result of the coexistence detection, the result of the first and second window timing confirmation, and the result of the beacon detection, Perform one of the following actions:
(1B) First transmission:
The coexistence signal and the beacon signal are generated and transmitted in two cases, when both the beacon signal and the coexistence signal are not detected and when the detection of the plurality of band windows is not confirmed in the first window timing confirmation. To do.
(2B) Second transmission:
When the detection of the plurality of band windows is confirmed by the first window timing confirmation, the window timing is made common to generate and transmit the coexistence signal with the window timing made common and the indicator signal.
(3B) Current status maintenance:
When the detection of the plurality of band windows is not confirmed in the second window timing confirmation, the window timing sharing, the coexistence signal, and the beacon signal are not generated and transmitted.
(4B) Window timing sharing:
When the detection of the plurality of band windows is confirmed in the second window timing confirmation, the coexistence signal and the beacon signal are not generated and transmitted.

The start-up operation method according to the third aspect of the present invention includes a coexistence detection step of detecting timing of the coexistence signal and the band window from a received signal in response to an input of a start instruction, and the coexistence signal is detected by the coexistence detection. A window timing confirmation step for checking whether the plurality of coexistence signals are detected in the plurality of band windows whose periods are shifted when detected, and the detection of the plurality of coexistence signals is not confirmed by the window timing confirmation. A sign detection step for detecting the sign signal from the received signal in a case, and a window timing sharing step for aligning the timings of the plurality of band windows when the plurality of coexistence signals are confirmed by the window timing confirmation; A signal generation step for generating the coexistence signal and the beacon signal, and a transmission step for transmitting the coexistence signal and the beacon signal, Result of output, said window timing check result based on said at least one result of the result of the label detection, to perform any of the following operations.
(1C) First communication operation:
When the coexistence signal is not detected and the coexistence signal is detected in the band window of a predetermined period, but the beacon signal is not detected, the coexistence signal and the beacon signal are generated and transmitted. .
(2C) Second transmission:
When the detection of the plurality of band windows is confirmed by the window timing confirmation, the window timing is made common to generate and transmit the coexistence signal with the window timing made common and the indicator signal.
(3C) Current status maintenance:
When the detection of the plurality of band windows is not confirmed by the window timing confirmation, the window timing commonization, the coexistence signal, and the beacon signal are not generated and transmitted.
(4C) Common window timing:
This is an operation when generation and transmission of the coexistence signal and the beacon signal are not performed when the detection of the plurality of band windows is confirmed by the window timing confirmation but the beacon signal is detected by the beacon detection.

  ADVANTAGE OF THE INVENTION According to this invention, the operation | movement at the time of starting of a power line communication apparatus can be performed appropriately.

  Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, the apparatus connection form of the power line communication system which concerns on this embodiment is shown. FIG. 1 shows a schematic configuration of a power line communication system using two in-house power lines 111 and 112.
Wall sockets WS1 and WS3 are provided branched from the main line of the electric light line 111, respectively.
For example, the AC cord of the communication device 1-1 such as a PLC modem is connected to the wall outlet WS1. A device 71 such as a personal computer (PC) is connected to the communication device 1-1 via a LAN cable or the like.
The wall outlet WS3 is connected to another device 73 that is not related to communication, such as a printer, for example, and reflection or the like here causes a reduction in communication quality.

On the other hand, a wall outlet WS2 is provided branching off from the main line of the power line 112 laid in another house.
For example, the AC cord of the communication device 1-2 such as a PLC modem is connected to the wall outlet WS2. A device 72 such as a PC is connected to the communication device 1-2 via a LAN cable or the like.

  As shown in FIG. 1, power line carrier communication is communication that uses a power line as a transmission line, and it is not necessary to newly wire a communication line indoors, and is expected to be a highly convenient communication means.

There are two types of power line carrier communications that use power lines: 150 [kHz] to 450 [kHz] and 2 [MHz] to 30 [MHz]. In Japan, the former frequency band is used. Only the devices used are authorized.
In recent years, communication devices that use the latter frequency band have been approved in the United States, and in Japan, usage conditions are currently being studied for approval. Since the communication device using the latter frequency band is capable of high-speed transmission, various uses have been proposed, and it is expected that it will spread in the future.

High-speed communication is possible using 2 [MHz] to 30 [MHz], but there is a wide bandwidth from 100 [MHz] to 200 [MHz] like wireless LAN, and it is divided into multiple channels. I can't use it.
Therefore, in power line communication, one channel must be shared by different communication devices (modems).

FIG. 2 is a diagram for explaining the inter-modem interference in the same house, and FIG. 3 is a diagram for explaining the inter-modem interference in different houses.
In FIG. 2, an electric lamp line 111 is disposed in a house 107, and the electric lamp line 111 is connected to an unillustrated outdoor power line via a distribution board 102.
A device 71 is connected to the power line 111 via the communication device 1-1, a communication device 74 is connected via the communication device 1-2, a device 75 is connected via the communication device 1-3, and The communication device 1-4 is connected. FIG. 2 shows visual home appliances in which the devices 71 and 74 are PCs and the device 75 is capable of recording and reproducing video. The communication devices 1-1 to 1-4 are PLC modems.

Consider the case where the communication apparatuses 1-1 and 1-2 are communicating with each other in FIG. 2 and the communication apparatuses 1-3 and 1-4 are communicating with each other. The communication path at this time is indicated by a solid line in FIG.
When such two communications are performed via the same power line 111, as shown by the broken line in FIG. 2, the mutual communication interferes, which increases the noise component of the power line 111 and interferes with each other. It becomes a factor.

  In FIG. 3, it is assumed that devices 71 and 74 communicate with each other via a power line 111 in a house 107. At the same time, let us consider a case where another house 108 starts communication independently. A device 72 is provided on the power line 112 in the house 108, and a signal is transmitted to the outdoors using its communication function. The signal is transmitted from the distribution board 104 through the power line 10 to the repeater 106 provided in the utility pole or the like. This signal is transmitted from the repeater 106 to the power line 111 in the house 107 through the other power line 10 and the distribution board 102. At this time, in the house 107, since the devices 71 and 74 are communicating, the signal from the outside may become an interference wave.

Next, power line communication specifications, particularly band reservation for realizing system coexistence and band allocation for data communication will be described.
Hereinafter, it is assumed that a CDCF signal is used as the coexistence signal. The coexistence signal may be referred to by another name depending on the power line communication specification, and the CDCF signal is an example.

FIG. 4 is a schematic explanatory diagram of bandwidth allocation.
In the illustrated power line communication specification, this cycle is repeated with the CDCF window 120 as a bandwidth window having a predetermined time width and the subsequent slots 130A, 130B, 130C,. ing.
The CDCF window 120 is a “band window in which coexistence signals for band reservation for coexisting a plurality of systems having different modulation schemes can be allocated at different timings for each system”, and slots 130A, 130B, 130C, ... is a “communication band in which arbitrary information can be assigned to different time domains for each system”.

FIG. 5B schematically shows the configuration of the CDCF window 120, and FIG. 5C schematically shows the configuration of the slot 130i (i: arbitrary alphabet).
The CDCF window 120 is divided into several blocks. FIG. 5B shows only a block for transmitting a CDCF signal. In the figure, the CDCF signal 121 of the system # 1 is transmitted in the block 120A, and the CDCF signal 122 of the system # 2 is transmitted in the block 120B. Block 120C corresponds to system # 3, but no CDCF signal is transmitted in the figure. Blocks are provided according to systems that can coexist. The timing within the CDCF window (band window) of the CDCF signal (coexistence signal) is determined depending on which block has the CDCF signal.

  In addition, when the block of the CDCF window 120 is provided in, for example, a home system system application and an access system system, for example, by dividing the frequency, if the block of the in-use and use request display is divided for each system, the presence of the access system Displays the difference between display, time division multiplex (TDM) and frequency division multiplex (FDM), and blocks for requesting indication and requesting that it is a best-effort transmission system instead of bandwidth reservation. , May have various blocks. A block for changing the timing within the band window of the CDCF signal is also provided, and the system can be changed using this block.

  Thus, these blocks are meaningful in the domain (time domain, ie, timing or frequency domain), so it is important in which block the CDCF signal is transmitted. That is, in FIG. 5B, since a CDCF signal is set up in the blocks 120A and 120B, it can be seen that band reservation is performed or performed for coexistence in the systems # 1 and # 2.

Corresponding to the specifications of the CDCF window 120, the usage of the slots 130A, 130B, 130C,.
As shown in FIG. 5C, each slot includes a subslot 131 for best effort, a subslot for data transmission by the number of systems assumed by the CDCF window 120, and in this example, a TDMA subslot 132. , 133,...
When the system # 1 CDCF signal 121 is present in the CDCF window 120, the TDMA subslot 132 of each slot is available, and when the system # 2 CDCF signal 122 is present in the CDCF window 120, each The TDMA subslot 133 of the slot can be used, and this relationship is the same in other systems.
Band reservation is possible using this configuration. When bandwidth reservation is not performed, the subslot 131 for best effort is used, but the transmission rate is affected by the usage rate. On the other hand, in the case of bandwidth reservation, preferential use of the used area is ensured by transmitting the CDCF signal, and the influence of other systems is eliminated.

Thus, the purpose of the CDCF signal is to arbitrate so that the transmission areas of data and control signals used by modems of different systems do not overlap, and are different from beacon signals that are beacon signals in each system.
In order to notify the existence of a master station in each system, the beacon signal is normally transmitted at a fixed interval defined for each system as long as the master station is activated. The beacon signal is transmitted using the slot 130i as shown in FIG. The figure shows a state in which a beacon signal 141 of system # 1 and a beacon signal 142 of system # 2 are transmitted.
For this reason, in order for the master station to transmit a beacon signal, it is necessary to reserve a band using the CDCF signal first.
Further, since the beacon signal is a signal unique to the system, it cannot be detected if the systems are different. Therefore, for the two types of beacon signals shown in FIG. 5, only the beacon signal 141 can be seen (detected) from the system # 1, and only the beacon signal 142 can be seen from the system # 2.

When a communication device such as a modem is activated, a plurality of CDCF signals may be detected and a beacon signal may or may not be detected. When multiple CDCF signals are detected, arbitration between different systems is necessary. Also, mediation work in the system may be necessary.
In-system arbitration using a beacon signal basically depends on each modem manufacturer.
In this embodiment, the process up to the detection of the beacon signal is performed, and thereafter, the communication device that detects the beacon signal exchanges a control signal with the source master station to perform arbitration in the system. Is called.

On the other hand, since the bandwidth allocation of the subsequent data area (for example, usable subslots in the slot) is determined based on the CDCF window as a time reference, when the systems can detect each other by the CDCF signal, the timing of the CDCF window Need to match. This is because in the coexistence rule using the CDCF signal, if the bandwidth reservation is performed in a state where the timings of the CDCF windows are not matched, the bandwidth reservation cannot be performed under the coexistence rule, and there is a high probability that the signals interfere with each other.
The operation for matching the timings of the CDCF windows, or the operation for matching, is hereinafter referred to as “common window timing”.

  Which of the plurality of detected CDCF signals is that of the own system can be determined by detecting a beacon signal and reading subsequent system information. Since system information (for example, system ID) usually requires 32 bits or more, this information cannot be exchanged by coexistence using a CDCF signal. The coexistence using the CDCF signal only defines a rule for allocating the allocation area for each data system in time series (or divided into frequency bands) so that the data of each system does not collide. Because there is no.

6A to 6C show examples of subslot allocation.
In this example, as shown in FIG. 6 (A), the CDCF window 120 is repeated at a predetermined time pitch (period), for example, 100 to 200 [ms], and the interval between the CDCF windows 120 is further set to a predetermined time interval, For example, it is divided into 10 to 20 [ms] and is time-divided into n slots 130i (i = 1, 2, 3, 4,..., N-1, n).
Each CDCF window 120 has five blocks 120A, 120B, 120C, 120D, and 120E, as shown in FIG. Each slot area 130i is time-divided into four sub slots (131, 132, 133, 134 in this example).
The presence of a CDCF signal in the first block 120A of the CDCF window 120 means that data transmission using the subslot 131 is possible. Similarly, if a CDCF signal exists in the block 120B, this means that data transmission using the subslot 132 is possible, and if a CDCF signal exists in the block 120C, that means data using the subslot 133. This means that transmission is possible, and if a CDCF signal exists in the block 120D, this means that data transmission using the subslot 134 is possible.
In this example, the subslot 131 is assigned to best effort data transmission, and the other three subslots 132, 133, and 134 are assigned to band guaranteed data transmission. Subslots 132, 133, and 134 are associated with systems # 1, # 2, and # 3, respectively.

The last block 120E in the CDCF window 120 is a block for requesting timing change of the CDCF window. If there is a window timing change request signal in this block 120E, the master station of the other system that has detected this window timing change request signal must change the transmission timing of the CDCF window used by itself.
The transmission timing of the CDCF window can be determined with respect to the power supply cycle, for example. That is, when the time pitch (period) of the CDCF window 120 is 200 [ms], for example, if the timing can be changed every 1/6 period of the power source, there are 60 timings that the CDCF window can take. Upon receiving the CDCF window timing request signal, the master station changes the CDCF window to any one of 59 ways other than the window timing currently used by the own system. At this time, the master station that has received the timing request signal of the CDCF window searches for a CDCF signal other than the CDCF signal of its own system, and when the CDCF signal of the other system can be detected, the window timing including the CDCF signal of the other system. In addition, it is possible to transfer from the window timing of the own system.
By performing the transmission of the window timing change request signal and the confirmation of the window timing until the window timings match, the above-described window timing can be shared.
As described above, when the CDCF signals of the own system or of other systems can be correctly received and the systems are in a relationship of interfering with each other, it is possible to share the window timing and avoid data collision.

FIG. 7 schematically shows three systems (houses here).
Now, in the house 1, the modem 1-1 and the modem 1-2 are communicating via the power line, and in the house 3, the modem 3-1 and the modem 3-2 are communicating.
At this time, since the length (distance) of the power line 10 between the houses 1 and 3 is long and the system of the house 2 located between the houses 1 and 3 is stopped, it is assumed that there is almost no communication interference.
In this case, the detection level at the house 1 of the CDCF signal from the house 3 is conversely the interference level even if the detection level at the house 3 of the CDCF signal from the house 1 cannot be detected or detected. It is a level small enough not to be. Therefore, the two operating systems can operate independently.

Consider the case where the modem 2-1 or 2-2 of the house 2 is activated while the houses 1 and 3 are communicating in FIG.
FIG. 8 shows the system interference at that time. FIG. 9 shows an example of signals observed when the modem in the house 2 is activated.

  When the system of the house 2 is activated, the two CDCF signals transmitted by the system of the house 1 and the house 3 are detected from the house 2 at a sufficient level. However, as shown in FIG. 9, two types of CDCF signals having different window timings (that is, the period of the band window being shifted) are observed, and each system also observes its own beacon signal following each CDCF signal. May be.

  As described above, since the CDCF signal does not contain detailed information, it is not known which system the device itself should operate when the house 2 is activated. At this time, a beacon signal is sent following each of the two CDCF signals, and when the house 2 receives one of the beacon signals, the CDCF signal does not contain detailed information, so the received beacon signal It cannot be determined which CDCF signal is being transmitted.

  Further, if the house 2 starts signal transmission without performing an appropriate startup operation, the signal S2 transmitted by the system of the house 2 interferes with the systems of the house 1 and the house 3 as shown in FIG. Sometimes. Therefore, in the start-up operation of the house 2, it is necessary to avoid interference using the CDCF signal.

In the present embodiment, an efficient operation procedure is proposed for the arbitration work using the CDCF signal and the arbitration work using the beacon signal without any deficiencies when the modem is activated.
In the present embodiment, appropriate detection of a CDCF signal and a beacon signal is performed, and an operation based on the detection is performed. When there are CDCF windows having different timings at that time, an operation for matching the window timings (window timings). Common). As a result, the signal level causing system interference is reduced as much as possible.
When the timing of the two CDCF windows is matched and the house 2 in FIG. 8 performs signal transmission according to the matched window timing, on one of the two systems (houses 1 and 3) that sent the two CDCF signals, The possibility that the signal from the house 2 becomes an interference wave is greatly reduced.

  The above is the premise and outline of the present embodiment, but a specific configuration and operation of the communication apparatus will be described below.

<< First Embodiment >>

FIG. 10 is a block diagram of the communication apparatus of this embodiment.
The illustrated communication apparatus includes a reception amplifier 11, a demodulator 12, and an error detection unit 15. These three blocks correspond to the “reception processing unit” of the present invention. The reception processing unit is a circuit that receives and processes a reception signal from a power line communication network (not shown).
The reception amplifier 11 is a gain amplifier that can change the gain of the reception signal.
The demodulator 12 is a circuit that converts the received signal after gain adjustment into a digital signal, performs demodulation by a method according to a predetermined modulation method when the received signal is generated at the time of transmission, and converts it into digital data. .
The error detection unit 15 is a circuit or software part that can determine whether or not there is an error (error detection) from digital data and is configured to extract received data (packets).

The communication apparatus of FIG. 10 includes a packet processing unit 14, a selection circuit 35, a modulator 16 as a “transmission processing circuit”, and a transmission amplifier 17.
The packet processing unit 14 is a circuit that confirms the destination of the received data packet and performs other necessary packet processing. The packet processing unit 14 is connected to an upper layer block 30 that further processes the data after packet processing.

A modulator 16 and a transmission amplifier 17 are connected in cascade to the packet processing unit 14 via a selection circuit 35.
The modulator 16 modulates a carrier wave (AC power supply wave) by a predetermined modulation method using transmission data (packets) sent from the upper layer block 30 via the packet processing unit 14 and the selection circuit 35. Is a circuit for generating a transmission signal.
The transmission amplifier 17 is a circuit that adjusts the gain of the transmission signal. From the transmission amplifier 17, the transmission signal after gain adjustment can be sent to a power line communication network (not shown).

  The communication apparatus of this embodiment shown in FIG. 10 includes a beacon signal detection unit 31 as a “sign signal detection unit”, a CDCF signal detection unit 32 as a “coexistence signal detection unit”, and a “sign signal generation unit”. A beacon signal generation unit 33, a CDCF signal generation unit 34 as a “coexistence signal generation unit”, a selection circuit 35 that selects a generated beacon signal or CDCF signal (or other packet) and outputs the selected signal to the modulator 16; Furthermore, it has the control part 20 for controlling these and performing the operation | movement at the time of this embodiment.

The outputs of the reception amplifier 11 are connected to the inputs of the beacon signal detection unit 31 and the CDCF signal detection unit 32, so that the reception signal can be detected.
The beacon signal detection unit 31 and the CDCF signal detection unit 32 can output the respective detection results to the control unit 20.
The beacon detection result includes not only the presence / absence of the beacon detection but also the timing (identification of the slot and the subslot in the area). The detection result of the CDCF signal includes not only the presence / absence of reception of the CDCF signal but also the timing of the band window (window timing) to which the CDCF signal is assigned.
Therefore, the control unit 20 knows whether the detected beacon signal or CDCF signal corresponds to its own system or another system when holding its own system information in a changeable manner. Can do.

  The beacon signal generator 33 and the CDCF signal generator 34 are circuits that generate a beacon signal and a CDCF signal under the control of the control unit 20, respectively. The generated beacon signal and CDCF signal are selected by the selection circuit 35 under the control of the control unit 20 and can be input to the modulator 16.

  Next, the basic operation of the communication apparatus of FIG. 10 will be described.

When the reception signal is input to the reception amplifier 11, the reception amplifier 11 adjusts the gain of the reception signal, and predetermined processing is performed by the demodulator 12, the error detection unit 15, and the packet processing unit 14.
The demodulator 12 demodulates the received signal, and the error detector 15 performs error detection (and error correction). Received data (packet data) is output from the data extraction unit 13 to the packet processing unit 14.
The packet processing unit 14 determines whether the packet is to be received and processed by the apparatus, and if so, the received data is passed to the next processing (upper layer).

On the other hand, the received signal whose gain has been adjusted by the receiving amplifier 11 is also input to the beacon signal detecting unit 31 and the CDCF signal detecting unit 32.
The beacon signal detection unit 31 detects a beacon signal and inputs the result to the control unit 20. The CDCF signal detection unit 32 detects the CDCF signal and inputs the result to the control unit 20.

  Based on the results from the beacon signal detector 31 and the CDCF signal detector 32, the controller 20 generates a beacon signal by the beacon signal generator 33, generates a CDCF signal by the CDCF signal generator 34, and generates these signals. The transmission operation selected by the selection circuit 35 and transmitted from the transmission amplifier 17 via the modulator 16 is controlled. Further, the control unit 20 can perform in advance the process of sharing the timing of the band window that determines the transmission timing of the CDCF signal prior to transmission. This common processing may or may not be executed depending on the detection result of the beacon signal or the CDCF signal.

In addition to the basic control of the control unit 20, when the communication apparatus transmits a CDCF signal, the CDCF window to which the signal should be transmitted can be specified as an additional arbitrary control or process.
Further, when the CDCF signal is not detected, the control unit 20 can instruct the CDCF signal generation unit 34 to generate a CDCF signal transmission request signal. Upon receiving this instruction, the CDCF signal generator 34 generates a CDCF signal transmission request signal.
Furthermore, when a beacon signal cannot be detected, the control unit 20 can instruct the beacon signal generation unit 33 to generate a beacon signal transmission request signal. Receiving this instruction, the beacon signal generation unit 33 generates a beacon signal transmission request signal.
These request signals are selected by the selection circuit 35 under the control of the control unit 20 and are transmitted from the transmission amplifier 17 via the modulator 16. The control unit 20 controls the timing of generation, transmission, or both of the transmission request signal at this time.

In the case of normal data transmission, the data received from the upper layer is packetized by the packet processing unit 14 and input to the selection circuit 35.
The selection circuit 35 selects one of the transmission packet from the packet processing unit 14, the beacon signal packet from the beacon signal generation unit 33, and the CDCF signal packet from the CDCF signal generation unit 34, and sends it to the modulator 16. input. The modulator 16 modulates the received transmission packet and inputs the result to the transmission amplifier 17. In the transmission amplifier 17, it amplifies to predetermined electric power and outputs it to a power line communication network.

Next, a more detailed control procedure of the control unit 20 will be described.
The following describes three procedures, but the present invention is not limited to this. This embodiment including the three procedures has the following characteristics.

  The control unit 20 includes the presence / absence of a CDCF signal (coexistence signal) detected by the CDCF signal detection unit (coexistence signal detection unit) 32, the timing of the CDCF window (band window), and a beacon signal detection unit (sign signal detection unit) 31. On the basis of the presence or absence of a beacon signal (identification signal) detected by, each operation for each of the following cases: (1) first transmission, (2) second transmission, (3) current status maintenance, (4) window timing Either one of the common operations is executed, or an execution instruction is given to the beacon signal generation unit (sign signal generation unit) 33 and the CDCF signal generation unit (coexistence signal generation unit) 34.

(1) First transmission:
The transmission amplifier 17 in the transmission processing unit generates the CDCF signal and the beacon signal when at least one of the case where the CDCF signal is not detected and the case where the CDCF signal is detected in the CDCF window of a predetermined period but the beacon signal is not detected. Send from.
(2) Second transmission:
When a plurality of CDCF signals are detected in a plurality of CDCF windows whose periods are shifted but a beacon signal is not detected, the window timing is made common by aligning the timings of the plurality of CDCF windows. The CDCF signal and the beacon signal are transmitted from the transmission amplifier 17 in the transmission processing unit.
(3) Current status maintenance:
When a CDCF signal is detected in a CDCF window of a predetermined period and a beacon signal is detected, window timing sharing, generation of CDCF signal and beacon signal and transmission are not performed at all.
(4) Common window timing:
When a plurality of CDCF signals are detected in a plurality of CDCF windows whose periods are shifted and a beacon signal is detected, generation and transmission of the CDCF signal and the beacon signal are not performed.

  The above operations (1) to (4) are not intended to limit the procedure for signal detection and the like in that case, and this embodiment and the subsequent embodiments (second and third embodiments) follow. Commonly applied. In the first to third embodiments, specific examples of the above procedure are shown.

  In the present embodiment, as an example, the startup operation is performed according to the procedure of first detecting the CDCF signal and the beacon signal in this order, and then checking whether there are a plurality of CDCF windows whose periods are shifted (window timing confirmation).

  An operation flow according to this procedure is shown in FIG. 11, and a more specific control example will be described with reference to FIG.

The specific control of the present embodiment exemplifies a case where the control unit 20 grasps the relationship between the system to which the control unit 20 belongs (the own system) and another system to which each of the detected CDCF signal and beacon signal corresponds. .
This system can be grasped by detecting a beacon signal and reading subsequent system information. Further, the relationship between the CDCF signal and the beacon signal can be grasped after both are detected. The window timing confirmation is an operation for obtaining a criterion for determining whether to unify (commonize) the window timings necessary for signal generation or transmission, and corresponds to reconfirmation of the detection result of the CDCF signal.

  Activation is detected by the control unit 20 at step ST0 in FIG. Here, “startup” includes both the case where the power is turned on, and the case where the communication apparatus (modem) is activated from the standby state in which the function of the communication device (modem) is suspended.

After the activation, the CDCF signal detection unit 32 in FIG. 9 detects whether the reception signal from the reception amplifier 11 includes the CDCF signal (step ST1A).
When the CDCF signal is not detected, the process flow proceeds to step ST10 for the above-mentioned “(1) first transmission”.
Since the beacon signal is transmitted later by another system that has transmitted the CDCF signal, the beacon signal cannot be detected when the CDCF signal cannot be detected.

  The operation of the first transmission is a procedure for making itself a master station because there is no other system activated, and the control unit 20 in FIG. 9 performs the selection of the CDCF signal generation unit 34, the beacon signal generation unit 33, and the selection. The circuit 35, the modulator 16 and the transmission amplifier 17 are controlled and executed.

In step ST10, transmission of the CDCF signal is started at the timing in the CDCF window corresponding to the own system (block 120i (i = A, B, C,...): See FIG. 5A) to reserve the band.
In step ST11, transmission of a beacon signal is started. This beacon signal is sent in the slot 130i corresponding to the own system.
Thereafter, the startup operation is terminated.

When the CDCF signal is detected in step ST1A in FIG. 11, the processing flow proceeds to step ST2A.
In step ST <b> 2 </ b> A, the beacon signal generation unit 33 in FIG. 10 detects whether a beacon signal is included in the reception signal from the reception amplifier 11.
If a beacon signal is not detected corresponding to the CDCF signal detected in step ST1A, another CDCF window is searched for in the next step ST3A, and if there are a plurality of CDCF windows by repeating step ST2A and this ST3A, The beacon signals corresponding to all of them are sequentially detected.

If a beacon signal is detected in the determination of the first step ST2A or the determination of step ST2A in the second and subsequent steps during the loop processing in which steps ST2A and ST3A are repeated, the process flow proceeds to step ST5A.
If the beacon signal cannot be detected even once by the loop processing and the beacon signal detection is performed for all the CDCF windows, the processing flow proceeds to the next step ST4A.

In step ST4A, it is confirmed whether there is another CDCF window, that is, another CDCF window having a period shifted from the CDCF window detected in step ST1A. This step ST4A corresponds to “first window timing confirmation” of the present invention.
If no other CDCF window is detected in this step ST4A, it is not possible to recognize its own system that it is permitted to participate in, or other systems that can participate from now on. The above processing is performed.

On the other hand, when another CDCF window whose period is different from the CDCF window detected in step ST1A is confirmed in step ST4A, “window timing sharing” is performed in the next step ST12.
Here, the window timing sharing is the window timing sharing for a plurality of other systems other than the own system. Here, the other system includes a system having a different system and a system having a system ID different from that of the same system.
For example, in the case of FIG. 9, consider a case where a certain other system is “system # 1” and the corresponding CDCF # 1 is repeatedly transmitted. In this case, the CDCF signal # 1 can be repeatedly detected at the same period (for example, 200 [ms]) as the window timing period. While searching for the CDCF signal, the CDCF signal # 3 may be detected alternately with the CDCF signal # 1. In this case, when only the CDCF signal # 3 is viewed, a constant period of 200 [ms] is maintained, but since the period is shifted from the period of the CDCF signal # 1, two types of CDCF signals are alternately observed. The
Such a shift in period is referred to as “window timing is different” or “window timing is shifted”. The common window timing is an operation for making one window timing cycle coincide with the other window timing cycle. Specifically, a window timing change request signal is generated by, for example, the CDCF signal generator 34 under the control of the control unit 20 in FIG. 10, selected by the selection circuit 35, and transmitted from the transmission amplifier 17 via the modulator 16. The The master station of system # 1 or # 3 that has received this window timing change request signal searches the CDCF signal, and if a window timing that is different from the window timing used by itself is detected, the master station uses it. The CDCF signal is transmitted by switching from the window timing to another window timing. The communication apparatus which has made the window timing change request can know that the window timing deviation has been corrected and the “window timing sharing” has been performed in the subsequent CDCF signal reception.
Thereafter, when a beacon signal is transmitted as necessary (step ST11), the start-up operation ends.

Next, returning to the flowchart of FIG. 11, processing when a beacon signal is detected in step ST2A will be described.
When a beacon signal is detected, the process flow proceeds to step ST5A, where presence of a plurality of CDCF windows is confirmed. The content of this process itself is the same as in step ST4A, but since it is after the detection of the beacon signal, it corresponds to the “second window timing confirmation” of the present invention.

When the determination in step ST5A is “No”, since one CDCF signal (CDCF window) and one beacon signal can be received, this communication apparatus can recognize the presence of the master station of its own system. Therefore, arbitration work is unnecessary, and the startup operation is terminated as “follow the control of the master station” shown in the state S of FIG.
In this case, since there is no specific state change (becomes a master station, system change, etc.) due to the execution of arbitration, this corresponds to the “(3) current maintenance”.

If the determination in step ST5A is “Yes”, the window timing sharing (ST12) described above is performed. However, since the beacon signal is detected and the existence of the master station of the own system has been confirmed, There is no need to become. Therefore, after the window timing is standardized, the start-up operation is terminated without performing the CDCF signal and beacon signal transmission processing (ST10 and ST11).
This case corresponds to the “(4) common window timing”. At this time, it follows the control of the master station of the system (the master station of the own system) that is transmitting the beacon signal (state S).

As described above, only one (one type) beacon signal can be detected because the beacon signal is unique to the system. However, if there are a plurality of CDCF windows whose periods are shifted (see periods # 1 and # 2 in FIG. 8), It is not known which CDCF window the signal was sent according to.
In this case, the beacon signal detection is performed in the subslot designated by the CDCF signal of each CDCF window to acquire the relationship between the CDCF timing and the beacon signal, and the CDCF window to which the beacon signal relates is specified.
If a beacon signal related to the own system is detected as a result of this determination, the control is performed by the master station of the own system (state S).

Arbitration is performed in the window timing standardization (ST12) performed when the determination in step ST5A is “Yes”. The method includes a CDCF window of the own system among a plurality of CDCF windows, and a period of the same. There are the following three types after discriminating the window timing that is shifted from the CDCF window of the system.
This arbitration operation is executed by the control unit 20 itself of FIG. 10 and the beacon signal generation unit 33, CDCF signal generation unit 34, selection circuit 35, modulator 16, and transmission amplifier 17 under the control.

[First arbitration method]
In the first arbitration method, the CDCF window of the other system is changed at the timing of the CDCF window used by the master station of the own system.

Specifically, for example, the following processing is possible.
The control unit 20 outputs a command for generating a window timing change request to be sent to another system to the CDCF signal generation unit 34. Based on this command, the CDCF signal generator 34 generates a window timing change request signal in a change request block (not shown in FIG. 5A) in the CDCF window defined in the CDCF signal specification, and transmits it. To do.
Thereafter, another system that has received this window timing change request signal changes the window timing. Then, the communication apparatus that has transmitted the window timing change request signal confirms that the CDCF signal is not transmitted in the CDCF window that has made the timing change request.
The CDCF signal arbitration is performed by repeating the window timing change request and the change confirmation once or, if necessary, a plurality of times.

[Second arbitration method]
In the second arbitration method, the CDCF window used by the own system is abandoned and switched to the CDCF window used by another system.
Specifically, a communication apparatus that is not itself a master station sends a window timing change request signal to a CDCF window that is used by the own system. In response to this window timing change request, the communication apparatus that is not the master station, in which the master station of its own system has changed the timing of the CDCF window, confirms the change of the window timing.

[Third arbitration method]
The third arbitration method is a method of determining which one of the first and second arbitration methods is selected according to the use status of the CDCF signal.
Here, the usage status refers to a difference between communication based on bandwidth reservation or so-called best effort communication.
In bandwidth reservation, content is transmitted while maintaining a predetermined transmission speed, so that when real-time processing such as download / playback or recording of content is necessary, it is suitable for an application where a minimum communication speed is desired. However, if the bandwidth reservation is frequently performed, the usable frequency or time band is subdivided, and there is a possibility that the bandwidth that cannot be used even if it is vacant may increase, and the usage efficiency may be poor.
On the other hand, in best-effort communication, all unreserved bands can be used, which may be efficient. However, if most of the bands are filled with reservations, the communication speed is limited, so the lowest communication speed is Cannot guarantee.

In the third arbitration method, first, the control unit 20 controls the CDCF signal detection unit 32 and examines such a usage situation in a plurality of CDCF windows.
As described above, in the CDCF signal, there is a time domain for best-effort communication that does not reserve a band, in addition to a time domain (CDCF block) for band reservation for each system. Since the control unit 20 can also detect the signal timing in the CDCF window from the detection result of the CDCF signal detection unit 32 in FIG. 9, it can also recognize the usage status of such a bandwidth reservation type or best effort type CDCF signal. is there.

  The control unit 20 causes a procedure for changing the window timing of the CDCF window for performing best effort communication to the window timing of another CDCF window for performing bandwidth reservation communication. In this case, it is irrelevant which is the CDCF window of the own system, and either the first arbitration method or the second arbitration method is executed so as to be unified with the bandwidth reservation type communication.

On the contrary, it is possible to unify to best effort type communication.
For example, the minimum speed guarantee is not necessary for an application assumed by the communication apparatus of the own device, and it is possible to unify the best effort communication when the reserved band is not used efficiently.
In any case, the startup operation is performed according to the selected first or second arbitration method.

<< Second Embodiment >>
In the present embodiment, the start-up operation is performed according to the procedure of first detecting the beacon signal regardless of the CDCF window and then detecting the CDCF signal.

This procedure is the same as that of the first embodiment except that the procedure is different. That is, the configuration of FIG. 10 is the same, and FIGS. 1 to 9 are also applied to this embodiment. In addition, the description of “(1) First transmission”, “(2) Second transmission”, “(3) Current status maintenance”, and “(4) Common window timing”, and any one of them are implemented or controlled. That the control unit 20 performs based on the presence / absence of the CDCF signal, the timing of the CDCF window, and the presence / absence of the beacon signal is the same as in the first embodiment.
This embodiment is different from the first embodiment in the procedure shown in FIG. 12, and this procedure will be described below.

  Activation is detected by the control unit 20 in step ST0 of FIG. Here, “start-up” includes both the case where the power is on, and the case where the communication apparatus (modem) is activated from the standby state where the function is suspended.

  After the activation, the beacon signal detection unit 31 in FIG. 10 detects whether or not the beacon signal is included in the reception signal from the reception amplifier 11 (step ST2B). A beacon signal can be detected without a CDCF window.

When the beacon signal is not detected, the CDCF signal detection unit 32 in FIG. 10 detects whether the reception signal from the reception amplifier 11 includes the CDCF signal (step ST1B).
When the CDCF signal is not detected, the processing flow proceeds to step ST10 for the above-mentioned “(1) First activation”.

  The operation of the first transmission is a procedure for making itself a master station because there is no other system that is activated, and the control unit 20 in FIG. 10 selects the CDCF signal generation unit 34, the beacon signal generation unit 33, and the selection. The circuit 35, the modulator 16 and the transmission amplifier 17 are controlled and executed.

In step ST10, transmission of a CDCF signal is started in an unused block 120i in the CDCF window to reserve a band.
In step ST11, transmission of a beacon signal is started. This beacon signal is transmitted using the reserved subslot 130i.
Thereafter, the startup operation is terminated.

When the CDCF signal is detected in step ST1B in FIG. 12, the processing flow proceeds to step ST4B.
In step ST4B, it is confirmed whether there is another CDCF window, that is, another CDCF window having a period shifted from that detected in step ST1B. This step ST4B corresponds to “first window timing confirmation” of the present invention.
At this time, when a plurality of CDCF windows at different timings are detected, it is possible to know which CDCF window the beacon signal is transmitted according to. Specifically, by detecting the beacon signal in the subslot designated by the CDCF signal of each CDCF window, the relationship between the CDCF timing and the beacon signal can be acquired, and the CDCF window related to the beacon signal can be specified. This confirmation operation is an operation for obtaining a determination standard for unifying (commonization) of window timing executed later, and corresponds to reconfirmation of the detection result of the CDCF signal.

  When no other CDCF window is detected in this step ST4B, since the beacon signal is not detected, the own system cannot be recognized, and since there is only one type of CDCF window, it is not necessary to perform window timing sharing. The processing flow is shifted to step ST10, and the above-described processing to become the master station is performed.

On the other hand, in step ST4B, when another CDCF window whose period is different from that of the CDCF window detected in step ST1B is confirmed, “window timing sharing” is performed in the next step ST12.
The contents of the window timing sharing are the same as in the first embodiment.
That is, the window timing change request signal is generated by, for example, the CDCF signal generation unit 34 under the control of the control unit 20 in FIG. 10, selected by the selection circuit 35, and transmitted from the transmission amplifier 17 via the modulator 16. The master station of the system that has received this window timing change request signal searches the CDCF signal, and if a window timing that is different from the window timing used by itself is detected, the master station uses the window timing used by itself. Then, the CDCF signal is transmitted by changing to other window timings. The communication apparatus that has made the window timing change request can know that the window timing deviation has been corrected and the “window timing sharing” has been performed in the subsequent CDCF signal reception.
Thereafter, when a beacon signal is transmitted as necessary (step ST11), the start-up operation ends.

Next, processing when a beacon signal is detected in step ST2B of FIG. 12 will be described.
When a beacon signal is detected, the process flow proceeds to step ST5B, where the presence of a plurality of CDCF windows is confirmed. The content of this process is the same as that in step ST4B (that is, ST4A in the first embodiment), but corresponds to “second window timing confirmation” of the present invention because it is after the detection of the beacon signal.

When the determination in step ST5B is “No”, since one CDCF signal (CDCF window) and one beacon signal can be received, this communication apparatus can recognize the presence of the master station of its own system. Therefore, no arbitration work is required, and the startup operation is terminated as “follow the control of the master station” shown in the state S of FIG.
In this case, since there is no specific state change (becomes a master station, system change, etc.) due to the execution of arbitration, this corresponds to the “(3) current maintenance”.

If the determination in step ST5B is “Yes”, the window timing sharing (ST12) described above is performed. However, since the beacon signal is detected and the existence of the master station of the own system has been confirmed, There is no need to become. Therefore, after the window timing is standardized, the start-up operation is terminated without performing the CDCF signal and beacon signal transmission processing (ST10 and ST11).
This case corresponds to the “(4) common window timing”. At this time, it follows the control of the master station of the system (the master station of the own system) that is transmitting the beacon signal (state S).

As described above, only one (one type) beacon signal can be detected because the beacon signal is unique to the system. However, if there are a plurality of CDCF windows whose periods are shifted (see periods # 1 and # 2 in FIG. 8), It is not known which CDCF window the signal was sent according to.
In this case, the beacon signal detection is performed in the subslot designated by the CDCF signal of each CDCF window to acquire the relationship between the CDCF timing and the beacon signal, and the CDCF window to which the beacon signal relates is specified.
If a beacon signal related to the own system is detected as a result of this determination, the control is performed by the master station of the own system (state S).

<< Third Embodiment >>
In the present embodiment, the startup operation is performed according to the procedure of detecting the CDCF signal and standardizing the CDCF window first, and then detecting the beacon signal.

This procedure is the same as that of the first embodiment except that the procedure is different. That is, the configuration of FIG. 10 is the same, and FIGS. 1 to 9 are also applied to this embodiment. In addition, the description of “(1) First transmission”, “(2) Second transmission”, “(3) Current status maintenance”, and “(4) Common window timing”, and any one of them are implemented or controlled. That the control unit 20 performs based on the presence / absence of the CDCF signal, the timing of the CDCF window, and the presence / absence of the beacon signal is the same as in the first embodiment.
This embodiment is different from the first embodiment in the procedure shown in FIG. 13, and this procedure will be described below.

  Activation is detected by the control unit 20 in step ST0 of FIG. Here, “startup” includes both the case where the power is turned on, and the case where the communication apparatus (modem) is activated from the standby state in which the function of the communication device (modem) is suspended.

After the activation, the CDCF signal detection unit 32 in FIG. 10 detects whether the reception signal from the reception amplifier 11 includes the CDCF signal (step ST1C).
When the CDCF signal is not detected, the processing flow proceeds to step ST10 for the above-mentioned “(1) First activation”.

  The operation of the first transmission is a procedure for making itself a master station because there is no other system that is activated, and the control unit 20 in FIG. 10 selects the CDCF signal generation unit 34, the beacon signal generation unit 33, and the selection. The circuit 35, the modulator 16 and the transmission amplifier 17 are controlled and executed.

In step ST10, transmission of a CDCF signal is started in an unused block 120i in the CDCF window to reserve a band.
In step ST11, transmission of a beacon signal is started. This beacon signal is transmitted using the reserved slot 130i.
Thereafter, the startup operation is terminated.

When the CDCF signal is detected in step ST1C in FIG. 13, the process flow proceeds to step ST6.
In step ST6, the presence of a plurality of CDCF windows is confirmed. The content itself of this process is the same as step ST4A of the first embodiment. However, in the present embodiment, “window timing confirmation” is only in step ST6.

  If the CDCF window detected in step ST6 is single, that is, if the determination is “No”, the process flow proceeds to step ST2C.

  In step ST <b> 2 </ b> C, the beacon signal detection unit 31 in FIG. 10 detects whether or not a beacon signal is included in the reception signal from the reception amplifier 11.

  If no beacon signal is detected, the process flow proceeds to step ST10 for the above-mentioned “(1) first activation”, and the procedure for making itself a master station as described above, that is, transmission of a CDCF signal ( The beacon signal is transmitted (ST10) and ST10), and the startup operation is terminated.

On the other hand, when a plurality of CDCF windows whose periods are shifted in step ST6 are confirmed, “window timing sharing” is performed in the next step ST12.
The contents of the window timing sharing are the same as in the first embodiment.
In addition, when the determination in step ST2C following the sharing is “No” and the process proceeds to the generation and transmission processing (ST10 and ST11) of the CDCF signal and the beacon signal, the sharing and the processing of steps ST10 and ST11 are performed. The arbitration work including the three methods, [first arbitration method], [second arbitration method], and [third arbitration method] described in the first embodiment, are described in detail with respect to the first embodiment. Since it is the same, description here is abbreviate | omitted.

When a beacon signal related to the own system is detected in step ST2C, the system can be grasped. The system can be grasped by detecting a beacon signal and reading subsequent system information.
As a result, the communication apparatus can recognize the presence of the master station of its own system. Therefore, the arbitration work is unnecessary, and the start-up operation is terminated as “follow the control of the master station” shown in the state S of FIG. This master station is the master station of its own system that is transmitting a beacon signal.
In this case, since there is no specific state change (becomes a master station, system change, etc.) due to the execution of arbitration, this corresponds to the “(3) current maintenance”.

  In step ST2C, if the local system cannot be grasped, the control of the master station of another system different from the system identification information held by itself may be followed in the state S, but in that case, it is necessary to respond to the beacon signal. The operation is performed by a system change operation after the startup operation.

Note that the procedures in FIGS. 11 to 13 are merely examples, and other procedures can be applied within the scope of the present invention.
In the embodiment of the present invention described above, it is possible to execute an efficient operation procedure without any deficiencies at the time of starting the modem, regarding the arbitration work using the CDCF signal and the arbitration work using the beacon signal.

It is a figure which shows the apparatus connection form of the power line communication system in connection with embodiment. It is explanatory drawing of the interference between modems used in embodiment in the same house. It is explanatory drawing of the interference between modems used in embodiment between different houses. It is a schematic explanatory drawing of the band allocation used by embodiment. (A) is an allocation diagram of CDCF windows and beacon signals, (B) is a configuration diagram of CDCF windows (band windows), and (C) is a configuration diagram of communication bands. As a more specific example used in the embodiment, (A) is a band allocation diagram, (B) is a configuration diagram of a CDCF window (band window), and (C) is a configuration diagram of a communication band. It is a figure which shows three houses as a system used by embodiment. It is explanatory drawing when system interference arises between the houses of FIG. It is a figure which shows the example of a signal observed when the modem in the house 2 of FIG. 7 is started. It is a block diagram of the communication apparatus common to 1st-3rd embodiment. It is a flowchart which shows the operation | movement method at the time of starting of 1st Embodiment. It is a flowchart which shows the operation | movement method at the time of starting of 2nd Embodiment. It is a flowchart which shows the operation | movement method at the time of starting of 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1-1, 1-2 etc. Communication apparatus, 10 ... Power line, 11 ... Reception amplifier, 12 ... Demodulator, 14 ... Packet processing part, 15 ... Error detection part, 16 ... Modulator, 17 ... Transmission amplifier, 20 ... Control unit, 30 ... upper layer block, 31 ... beacon signal detection unit, 32 ... CDCF signal detection unit, 33 ... beacon signal generation unit, 34 ... CDCF signal generation unit, 35 ... selection circuit, 71,72 ... device, 111 ... 120 ... CDCF window, 120A, 120B, 120C ... CDCF window block, 121,122 ... CDCF signal, 130i ... slot, 131-133 ... subslot, 141,142 ... beacon signal

Claims (7)

Bandwidth windows that can allocate coexistence signals for bandwidth reservation between multiple systems with different modulation methods to different time domains for each system, and communication bands that can assign arbitrary information to different time domains for each system alternately And a power line communication device assigned at periodic timing,
A reception processing unit for receiving and processing signals from the power line communication network;
A coexistence signal detection unit capable of detecting the timing of the coexistence signal and the band window from the reception signal received by the reception processing unit;
A sign signal detector capable of detecting the sign signal from the received signal;
A coexistence signal generator for generating a coexistence signal;
A sign signal generator for generating an identification signal;
A transmission processing unit for processing a signal and transmitting it to the power line communication network;
Based on the presence / absence of the coexistence signal detected by the coexistence signal detection unit and the timing of the band window, and the presence / absence of the identification signal detected by the beacon signal detection unit,
When the coexistence signal is not detected and at least one of the case where the coexistence signal is detected in the band window of a predetermined period but the beacon signal is not detected, the coexistence signal and the beacon signal are generated and the transmission processing is performed. 1st transmission transmitted from the part,
When a plurality of the coexistence signals are detected in the plurality of band windows whose periods are shifted, but the marker signal is not detected, the window timing is determined by performing window timing commonization that aligns the timings of the plurality of band windows. A second transmission in which a common coexistence signal and a beacon signal are generated and transmitted from the transmission processing unit;
When the coexistence signal is detected in the band window of a predetermined period and the beacon signal is detected, the window timing is shared, the coexistence signal and the generation and transmission of the coexistence signal and the beacon signal are not all maintained, and
The window timing when the plurality of coexistence signals are detected in the plurality of band windows whose periods are shifted and the beacon signal is detected and the coexistence signal and the beacon signal are not generated and transmitted. Or a control unit that issues an execution instruction to the coexistence signal generation unit, the beacon signal generation unit, and the transmission processing unit. The control unit instructs the coexistence signal detection unit to detect the coexistence signal in response to an input of an activation instruction, and instructs the sign signal detection unit to detect the sign signal when a coexistence signal is detected, A window timing check is performed to check whether the plurality of coexistence signals are detected in the plurality of band windows whose periods are shifted by the coexistence signal detection unit in two cases of a case where a sign signal is detected and a case where no sign signal is detected. And performing the first transmission, the second transmission, the current status maintenance, and the window timing sharing based on at least one of the coexistence signal detection result, the beacon signal detection result, and the window timing confirmation result. The power line communication device according to claim 1, wherein the power line communication device executes or instructs one of The control unit instructs the beacon signal detection unit to detect the beacon signal, and instructs the coexistence signal detection unit to detect the coexistence signal when no beacon signal is detected. And when the beacon signal is detected by the beacon signal detection unit, the coexistence signal is detected by the coexistence signal detection unit in the plurality of band windows whose periods are shifted. A window timing check is performed to check whether the signal is detected, and the first transmission and the second transmission are performed based on at least one of the detection result of the beacon signal, the detection result of the coexistence signal, and the result of the window timing confirmation. The power line communication apparatus according to claim 1, wherein the current line maintenance or the window timing sharing is executed or instructed. The control unit instructs the coexistence signal detection unit to detect the coexistence signal in response to an input of an activation instruction, and when the coexistence signal is detected, the plurality of coexistence signals have a period set by the coexistence signal detection unit. A window timing check is performed to check whether the plurality of shifted band windows are detected, and if the detection of the plurality of coexistence signals is not confirmed by the window timing check, the indicator signal detection unit is instructed to detect the indicator signal. Then, based on at least one of the detection result of the coexistence signal, the result of the window timing confirmation, and the detection result of the indicator signal, the first transmission, the second transmission, the current status maintenance, and the window timing commonization The power line communication device according to claim 1, wherein the power line communication device executes or instructs one of Bandwidth windows that can allocate coexistence signals for bandwidth reservation between multiple systems with different modulation methods to different time domains for each system, and communication bands that can assign arbitrary information to different time domains for each system alternately And the operation method at the time of starting of the power line communication device assigned at periodic timing,
A step of coexistence detection for detecting timing of the coexistence signal and its band window from a received signal in response to an input of an activation instruction;
A sign detection step of detecting the sign signal from a received signal when the coexistence signal is detected in the coexistence detection;
A first window timing confirmation step for checking whether the coexistence signal is detected in the plurality of band windows whose periods are shifted in the coexistence detection when the sign signal is not detected in the sign detection;
A second window timing confirmation step for examining whether the coexistence signal is detected in the plurality of band windows whose periods are shifted in the coexistence detection when the sign signal is detected in the sign detection;
A step of common window timing for aligning timings of the plurality of band windows;
A signal generating step for generating the coexistence signal and the beacon signal;
Transmitting the coexistence signal and the beacon signal; and
Including
Based on the result of the coexistence detection, the result of the sign detection, and the result of at least one of the results of the first and second window timing confirmations, each operation for each of the following cases:
The coexistence occurs in two cases: a case where the coexistence signal is not detected and a case where the coexistence signal is detected but the indicator signal is not detected and the detection of the plurality of band windows is not confirmed in the first window timing confirmation. A first transmission for generating and transmitting a signal and said beacon signal;
When the sign signal is not detected but the detection of the plurality of band windows is confirmed by the first window timing confirmation, the window timing is shared and the coexistence signal and the sign signal are made common to the window timing. Second transmission to generate and transmit,
Current status of not sharing the window timing, generating and transmitting the coexistence signal and the beacon signal when the beacon signal is detected but the detection of the plurality of coexistence signals is not confirmed in the second window timing confirmation Maintenance and
When the beacon signal is detected and the detection of the plurality of coexistence signals is confirmed by the second window timing confirmation, the window timing is shared when the coexistence signal and the beacon signal are not generated and transmitted. An operation method at the time of starting the power line communication device. Bandwidth windows that can allocate coexistence signals for bandwidth reservation between multiple systems with different modulation methods to different time domains for each system, and communication bands that can assign arbitrary information to different time domains for each system alternately And the operation method at the time of starting of the power line communication device assigned at periodic timing,
A sign detection step of detecting the sign signal from the received signal in response to an input of an activation instruction;
A step of coexistence detection for detecting timing of the coexistence signal and the band window from a received signal when the beacon signal is not detected by the beacon detection;
A first window timing confirmation step for checking whether the coexistence signal is detected in the plurality of band windows whose periods are shifted in the coexistence detection when the coexistence signal is detected;
A second window timing confirmation step for checking whether the plurality of coexistence signals are detected in the plurality of band windows whose periods are shifted in the coexistence detection when the indicator signal is detected;
A step of common window timing for aligning timings of the plurality of band windows;
A signal generating step for generating the coexistence signal and the beacon signal;
Transmitting the coexistence signal and the beacon signal; and
Including
Based on the result of the coexistence detection, the result of the first and second window timing confirmation, and the result of at least one of the results of the sign detection, each operation for each of the following cases:
The coexistence signal and the beacon signal are generated and transmitted in two cases, when both the beacon signal and the coexistence signal are not detected and when the detection of the plurality of band windows is not confirmed in the first window timing confirmation. First transmission,
When the detection of the plurality of band windows is confirmed by the first window timing confirmation, the window timing is made common, and the coexistence signal with the window timing made common and the indicator signal are generated and transmitted. Send,
If the detection of the plurality of band windows is not confirmed in the second window timing confirmation, the window timing is shared, the coexistence signal and the beacon signal are not generated and transmitted at all, and the current state is maintained, and
When the detection of the plurality of band windows is confirmed by the second window timing confirmation, the window timing is shared when the coexistence signal and the beacon signal are not generated and transmitted. How the device starts up. Bandwidth windows that can allocate coexistence signals for bandwidth reservation between multiple systems with different modulation methods to different time domains for each system, and communication bands that can assign arbitrary information to different time domains for each system alternately And the operation method at the time of starting of the power line communication device assigned at periodic timing,
A step of coexistence detection for detecting timing of the coexistence signal and its band window from a received signal in response to an input of an activation instruction;
A window timing confirmation step for examining whether the plurality of coexistence signals are detected in the plurality of band windows whose periods are shifted when the coexistence signal is detected in the coexistence detection;
A sign detection step of detecting the sign signal from a received signal when the detection of the plurality of coexistence signals is not confirmed in the window timing confirmation;
A window timing sharing step for aligning the timings of the plurality of band windows when the plurality of coexistence signals are confirmed by the window timing confirmation;
A signal generating step for generating the coexistence signal and the beacon signal;
Transmitting the coexistence signal and the beacon signal; and
Including
Based on the result of the coexistence detection, the result of the window timing check, and the result of at least one of the results of the sign detection, each operation for each of the following cases:
When the coexistence signal is not detected and the coexistence signal is detected in the band window of a predetermined period, but the beacon signal is not detected, the coexistence signal and the beacon signal are generated and transmitted. First transmission,
A second transmission for generating and transmitting the beacon signal and the coexistence signal in which the window timing is shared by performing the window timing sharing when the detection of the plurality of band windows is confirmed in the window timing check;
If the detection of the plurality of band windows is not confirmed in the window timing confirmation, the window timing is shared, the coexistence signal and the generation and transmission of the beacon signal are not all maintained, and
When the detection of the plurality of band windows is confirmed by the window timing confirmation but the sign signal is detected by the sign detection, the window timing common when the coexistence signal and the sign signal are not generated and transmitted A method of operating the power line communication device at the time of startup.

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