JP2014150454A - Communication system and communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a second communication device to start communications at arbitrary timing and allow a first communication device to detect a communication speed of the second communication device while maintaining a communication speed of the first communication device.SOLUTION: A communication system comprises a first communication device 101 and a second communication device 102. When communications are started with the first communication device 101, the second communication device 102 transmits a wireless signal including a preamble, which will be described later, to the first communication device 101 at a communication speed of the second communication device 102. The preamble is formed of "1" and "0", which are alternately arranged. The first communication device 101 reads a preamble of a wireless signal from the second communication device 102 at a clock frequency double the highest communication speed or higher, and detects a communication speed of the second communication device 102 from a pattern of the read preamble. The first communication device 101 sets a communication speed of the first communication device 101 as the communication speed of the detected second communication device 102.

Description

  The present invention relates to a communication system and a communication apparatus.

  Conventionally, there is a technology for performing data communication after performing auto-negotiation when performing communication between two devices. For example, by adding communication mode information supported by itself to FLP (Fast Link Pulse) and transmitting the information to each other, the communication modes selected from the ones with the highest communication speed are sequentially selected. When the communication speed is determined, data communication is started between the communication devices.

  Patent Document 1 discloses a technique for detecting a communication speed by detecting an RSSI (Received Signal Strength Indication) level.

JP 2001-103024 A

  However, in the conventional communication technique, it is necessary to determine in advance a common communication method (for example, a communication method using FLP) for auto-negotiation between two communication devices, and before auto-negotiation is completed. took time. As a result, the conventional communication technique has a problem that it takes time to start data communication.

  The conventional communication technology that performs auto-negotiation is not suitable particularly when two communication devices are provided in different systems. This is because in order to implement FLP, it is necessary to synchronize two communication devices (need to match timing), and while performing FLP between communication devices, each system cannot communicate within the system. . In other words, the two communication devices need to match the communication speed in order to implement FLP, and therefore cannot communicate at the communication speed of each system different from the communication speed for implementing FLP.

  The present invention has been made in view of the above points, and an object of the present invention is to start communication at an arbitrary timing from the second communication device, and the first communication device An object of the present invention is to provide a communication system and a communication apparatus that can detect the communication speed of the second communication apparatus without changing the communication speed.

  The communication system of the present invention is a communication system including a first communication device and a second communication device, and the second communication device is configured to start communication with the first communication device when the first communication device starts communication. Transmitting a radio signal including a preamble configured by alternately arranging a value of 1 and a second value to the first communication device at a communication speed of the second communication device, wherein the first communication device The preamble of the radio signal transmitted from the second communication device is read at a clock frequency that is equal to or less than half of the assumed maximum communication speed, and the second communication device uses the read preamble pattern to read the preamble of the second communication device. A communication speed detection unit that detects a communication speed; and a communication speed setting unit that sets the communication speed of the first communication device to the communication speed of the second communication device detected by the communication speed detection unit. It is characterized by.

  In this communication system, the first communication device includes a communication speed storage unit that stores the preamble patterns at a plurality of communication speeds, and the communication speed detection unit is transmitted from the second communication device. Preferably, a pattern that matches the preamble pattern of the radio signal is extracted from the communication speed storage unit, and the communication speed of the pattern is detected as the communication speed of the second communication device.

  In this communication system, it is preferable that the communication speed setting unit sets the reception filter bandwidth of the filter unit in accordance with the communication speed of the second communication device detected by the communication speed detection unit.

  In this communication system, the first communication device includes a unique word storage unit that stores a known unique word, and a unique signal included in the wireless signal received at the communication speed set by the communication speed setting unit. A comparison unit that compares a word and a unique word stored in the unique word storage unit, and the unique word included in the received wireless signal matches the unique word in the unique word storage unit, It is preferable to perform data communication with the second communication device.

  In this communication system, the first communication device includes a unique word storage unit that stores a unique word of another communication device different from the first communication device, and the communication speed set by the communication speed setting unit. Is a communication speed of another communication device in which a unique word is stored in the unique word storage unit, a switching unit that switches from a unique word of the first communication device to a unique word of another communication device, A comparison unit that compares the unique word included in the wireless signal received at the communication speed set by the communication speed setting unit with the unique word switched by the switching unit; When the included unique word matches the unique word switched by the switching unit, data communication with the second communication device can be performed. It is preferred.

  The communication device of the present invention is a communication device used as the first communication device in the communication system.

  In the present invention, communication can be started from the second communication device at an arbitrary timing, and the first communication device can detect the communication speed of the second communication device while maintaining its own communication speed. it can.

It is a sequence diagram which shows operation | movement of the communication system which concerns on embodiment. It is the schematic which shows the structure of the communication system which concerns on embodiment. It is a block diagram which shows the structure of the 1st communication apparatus which concerns on embodiment. It is explanatory drawing of operation | movement of the 1st communication apparatus which concerns on embodiment. It is a flowchart which shows operation | movement of the 1st communication apparatus which concerns on embodiment.

  As shown in FIG. 2, the communication system according to the present embodiment includes a first communication device 101 provided in the first system 21 and a second communication device 102 provided in the second system 22. I have.

  The first communication device 101 and the second communication device 102 are adaptive variable rate receiving devices that can receive a radio signal by switching a plurality of communication speeds. That is, the first communication device 101 can change the communication speed according to the second communication device 102. The first communication apparatus 101 and the second communication apparatus 102 implement the communication between a plurality of systems operating at different communication speeds using the same clock frequency. The communication speed is the amount of data bits that can be transmitted per second. The unit of communication speed is bps (bits per second). Note that the communication device 1 is used when the first communication device 101 and the second communication device 102 are not distinguished.

  The second communication device 102 can start communication with the first communication device 101 at an arbitrary timing and at a communication speed (50 kbps) used in the second system 22. In this case, as shown in FIG. 1, the second communication device 102 transmits a radio signal to the first communication device 101 at a communication speed (50 kbps) used in the second system 22. That is, when the second communication apparatus 102 starts communication with the first communication apparatus 101, the second communication apparatus 102 transmits a radio signal including a preamble described later to the first communication apparatus 101 at the communication speed of the second communication apparatus 102. To do. The preamble is configured by alternately arranging a first value “1” and a second value “0”. The first value and the second value may be different voltage levels. That is, the voltage level as the first value “1” is not limited to the high level and may be at the low level, and the voltage level as the second value “0” is not limited to the low level but is at the high level. May be.

  When the first communication device 101 receives a radio signal from the second communication device 102, the first communication device 101 detects the communication speed of the second communication device 102 from the preamble of the radio signal. Thereafter, the first communication device 101 changes the communication speed of the first communication device 101 to the communication speed of the second communication device 102. That is, if the first communication speed of the first communication device 101 is 100 kbps, the first communication device 101 changes the communication speed from 100 kbps to 50 kbps. The first communication device 101 and the second communication device 102 perform data communication at a communication speed of 50 kbps. Thereafter, when communication between the first communication device 101 and the second communication device 102 is completed, the first communication device 101 returns the communication speed to the original. That is, the first communication device 101 changes the communication speed from 50 kbps to 100 kbps.

  Hereinafter, the configuration of the first communication device 101 used in the communication system of the present embodiment will be described.

  As shown in FIG. 3, the first communication device 101 includes an RF unit 11, a filter unit 12, and a baseband unit 13. As described above, the first communication device 101 is an adaptive variable rate receiving device.

  The RF unit 11 down-converts the radio signal from the second communication device 102 and then extracts the baseband signal.

  The filter unit 12 limits the band of the baseband signal output from the RF unit 11, removes unnecessary noise, and outputs a signal component to the baseband unit 13. The filter unit 12 changes the bandwidth to be passed (reception filter bandwidth) to the filter bandwidth notified from the filter control unit 36 described later. Note that the initial value of the bandwidth of the filter unit 12 is the filter bandwidth corresponding to the maximum communication speed.

  The baseband unit 13 processes the baseband signal output from the filter unit 12. The baseband unit 13 includes a demodulation unit 31, a synchronization unit 32, a communication speed setting unit 33, a communication speed storage unit 34, a communication speed detection unit 35, and a filter control unit 36. The baseband unit 13 further includes a unique word setting unit 41, a unique word storage unit 42, a unique word detection unit 43, and a reception control unit 44.

  The demodulator 31 demodulates the baseband signal output from the filter unit 12.

  The synchronization unit 32 establishes bit synchronization of the baseband signal demodulated by the demodulation unit 31.

  The communication speed setting unit 33 sets communication speeds of a plurality of systems (communication devices 1) that are scheduled to communicate.

  The communication speed storage unit 34 stores the communication speed set by the communication speed setting unit 33. Specifically, the communication speed storage unit 34 stores preamble patterns (bit strings) at a plurality of communication speeds.

  As illustrated in FIG. 4, the communication speed detection unit 35 reads the preamble of the radio signal transmitted from the second communication device 102 at a clock frequency that is twice the assumed maximum communication speed. That is, the communication speed detection unit 35 extracts the preamble pattern of the baseband signal (wireless signal) for which bit synchronization has been established by the synchronization unit 32 at the clock frequency. The maximum communication speed is the fastest communication speed that can be used in the communication system of the present embodiment. In the example of FIG. 4, the maximum communication speed is 100 kbps. In this case, the clock frequency is twice the maximum communication speed. That is, the clock frequency is a frequency corresponding to one half of the bit period at the maximum communication speed, and is 200 kHz (corresponding to a communication speed of 200 kbps) in the illustrated example. The clock frequency may be faster than twice the maximum communication speed. Preferably, the clock frequency is a power of 2 of the maximum communication speed.

  FIG. 4 shows a preamble pattern when the communication speed is 100 kbps, 50 kbps, and 25 kbps. When the communication speed is 100 kbps, when the communication speed detection unit 35 reads the preamble at the rising edge of the clock frequency (200 kHz), the preamble pattern is “1010110101010”. When the communication speed is 50 kbps, the preamble pattern is “11001101100”. When the communication speed is 25 kbps, the preamble pattern is “111100001111”.

  The communication speed detection unit 35 detects the communication speed of the second communication device 102 from the read preamble pattern. Specifically, the communication speed detection unit 35 determines whether or not the extracted pattern matches the pattern stored in the communication speed storage unit 34. When the extracted pattern matches the pattern of the communication speed storage unit 34, the communication speed detection unit 35 detects the communication speed of the matched pattern as the communication speed of the second communication device 102 and notifies the filter control unit 36 of it. . Then, the communication speed detector 35 outputs the baseband signal to the unique word detector 43.

  For example, when the communication speed detection unit 35 extracts a preamble pattern “11001101100” from the output waveform of the synchronization unit 32, the communication speed detection unit 35 determines whether the extracted pattern matches the pattern of the communication speed storage unit 34. Determine whether or not. In this case, the communication speed detection unit 35 determines that the communication speed is a pattern of 50 kbps. As a result, when the communication speed of the second system 22 (see FIG. 2) is 50 kbps, it is understood that the signal is from the second communication device 102 of the second system 22.

  On the other hand, if the extracted pattern does not match the pattern in the communication speed storage unit 34, the communication speed detection unit 35 outputs a baseband signal to the unique word detection unit 43 without performing notification to the filter control unit 36.

  The filter control unit 36 illustrated in FIG. 3 sets a filter bandwidth that is optimal for the communication speed notified from the communication speed detection unit 35 (communication speed of the second communication apparatus 102) and notifies the filter unit 12 of the filter bandwidth. The filter unit 12 changes the bandwidth to pass to the filter bandwidth notified from the filter control unit 36. Thereby, the filter control unit 36 and the filter unit 12 function as a communication speed setting unit that sets the communication speed of the first communication device 101 to the communication speed of the second communication device 102 detected by the communication speed detection unit 35. To do.

  The unique word setting unit 41 sets unique words of a plurality of systems (communication devices 1) scheduled to communicate.

  The unique word storage unit 42 stores the unique word set by the unique word setting unit 41.

  The unique word detection unit 43 detects a bit string of the unique word from the baseband signal sent from the communication speed detection unit 35. Then, the unique word detection unit 43 determines whether or not the detected bit string of the unique word matches the unique word stored in the unique word storage unit 42. In other words, the unique word detection unit 43 compares the unique word contained in the wireless signal received at the communication speed set by the filter control unit 36 with the unique word stored in the unique word storage unit 42. When the unique word included in the received wireless signal matches the unique word in the unique word storage unit 42, the unique word detection unit 43 sends a baseband signal to a subsequent circuit (not shown). In the subsequent circuit, signal processing is performed to receive data. That is, the first communication device 101 performs data communication with the second communication device 102. On the other hand, when the detected unique word does not match the unique word in the unique word storage unit 42, the first communication apparatus 101 interrupts reception and enters a reception standby state. The unique word detection unit 43 of this embodiment functions as a comparison unit.

  Next, the operation of the communication system according to the present embodiment will be described with reference to FIG. First, when the second communication device 102 starts communication with the first communication device 101, the second communication device 102 transmits a radio signal at an arbitrary timing and the communication speed of the second communication device 102. Then, the first communication device 101 receives a wireless signal (S1). Thereafter, in the first communication device 101, the RF unit 11 down-converts the signal (S2). Next, the filter unit 12 limits the band (S3). Thereafter, the demodulator 31 of the baseband unit 13 demodulates the signal (S4). Thereafter, the synchronization unit 32 establishes synchronization (S5). Thereafter, the communication speed detection unit 35 reads the preamble at the clock frequency, extracts the preamble pattern, and determines whether the pattern matches the pattern of the communication speed storage unit 34 (S6). When the detected pattern matches the pattern of the communication speed storage unit 34, the communication speed detection unit 35 detects the communication speed of the second communication device 102.

  Thereafter, the unique word detection unit 43 detects a unique word and determines whether or not the unique word matches the unique word in the unique word storage unit 42 (S7). If the detected unique word matches the unique word in the unique word storage unit 42, the payload is received (S8).

  In the communication system of the present embodiment described above, it is not necessary to perform time synchronization between the first communication apparatus 101 and the second communication apparatus 102, and communication is started from the second communication apparatus 102 at an arbitrary timing. can do.

  In addition, the first communication device 101 of the communication system according to the present embodiment reads the preamble of the radio signal from the second communication device 102 at a clock frequency that is twice or more the maximum communication speed, and reads the first preamble from the read preamble pattern. The communication speed of the second communication device 102 is detected. Thereby, in the communication system according to the present embodiment, it is not necessary to match the communication speed of the first communication apparatus 101 with the communication speed of the second communication apparatus 102 when detecting the communication speed of the second communication apparatus 102. That is, the first communication device can detect the communication speed of the second communication device 102 by receiving the radio signal at the same communication speed. As a result, data communication can be started quickly.

  As a modification of the present embodiment, the communication speed set by the filter control unit 36 is the communication of another communication device 1 (second communication device 102) in which the unique word is stored in the unique word storage unit 42. In the case of speed, the unique word detection unit 43 may function as a switching unit that switches from the unique word of the first communication device 101 to the unique word of another communication device 1. In this case, the unique word detection unit 43 functions as a comparison unit that compares the unique word included in the wireless signal received at the communication speed set by the filter control unit 36 with the switched unique word. When the unique word included in the received wireless signal matches the switched unique word, the unique word detection unit 43 performs data communication with the other communication device 1.

DESCRIPTION OF SYMBOLS 1 Communication apparatus 101 1st communication apparatus 102 2nd communication apparatus 12 Filter part (communication speed setting part)
34 Communication speed storage section 35 Communication speed detection section 36 Filter control section (communication speed setting section)
42 unique word storage unit 43 unique word detection unit (comparison unit, switching unit)

Claims (6)

A communication system comprising a first communication device and a second communication device,
The second communication device is:
When communication with the first communication device is started, a radio signal including a preamble in which first values and second values are alternately arranged is transmitted at the communication speed of the second communication device. 1 to the communication device,
The first communication device is:
The preamble of the radio signal transmitted from the second communication device is read out at a clock frequency that is at least twice as high as the assumed maximum communication rate, and the communication speed of the second communication device is determined from the read preamble pattern. A communication speed detection unit to detect;
A communication speed setting unit configured to set the communication speed of the first communication device to the communication speed of the second communication device detected by the communication speed detection unit. The first communication device is:
A communication speed storage unit for storing the preamble pattern at a plurality of communication speeds;
The communication speed detection unit extracts, from the communication speed storage unit, a pattern that matches the preamble pattern of the radio signal transmitted from the second communication device, and determines the communication speed of the pattern as the second communication It detects as a communication speed of an apparatus. The communication system according to claim 1 characterized by things.   The said communication speed setting part sets the receiving filter bandwidth of a filter part according to the communication speed of the said 2nd communication apparatus detected by the said communication speed detection part, The Claim 1 or 2 characterized by the above-mentioned. Communications system. The first communication device is:
A unique word storage unit for storing known unique words;
A comparison unit that compares the unique word contained in the wireless signal received at the communication speed set by the communication speed setting unit with the unique word stored in the unique word storage unit;
The data communication with the second communication device is performed when a unique word included in the received wireless signal matches a unique word in the unique word storage unit. The communication system according to claim 1. The first communication device is:
A unique word storage unit for storing a unique word of another communication device different from the first communication device;
When the communication speed set by the communication speed setting unit is the communication speed of another communication device in which a unique word is stored in the unique word storage unit, the unique word of the first communication device is changed to another A switching unit for switching to a unique word of the communication device;
A comparison unit that compares a unique word included in a wireless signal received at the communication speed set by the communication speed setting unit and a unique word switched by the switching unit;
The data communication with the second communication device is performed when the unique word included in the received wireless signal matches the unique word switched by the switching unit. The communication system according to any one of the above.   The communication apparatus used as a said 1st communication apparatus in the communication system of any one of Claims 1-5.

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