JP2006180003A - Semiconductor integrated circuit for wireless communication, wireless communication apparatus, and its program and operating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication control technology and a wireless communication apparatus in which the reliability of communication can be enhanced by evaluating the reliability of received data in synchronous packet communication having no resending function like Bluetooth communication. <P>SOLUTION: In synchronous packet communication having no resending function like Bluetooth communication, an initial value of data reliability is determined based on the type of a received packet, at first, and then the initial value of data reliability is corrected downward by a detection value obtained through RSSI function and a detection value obtained through carrier sense function by utilizing the RSSI (received signal strength indication) function or the carrier sense function for monitoring a transmission path being employed generally in a communication apparatus thus obtaining the evaluation value of reliability of received data. In case of voice communication or motion picture communication, already received data is interpolated when a decision is made that the reliability is low from the evaluation value of reliability of received data. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wireless communication control technique and a technique for evaluating the reliability of received data in wireless communication having no retransmission function and improving the reliability of wireless communication, for example, for wireless communication that performs transmission / reception processing of packets of the Bluetooth communication standard. The present invention relates to an IC (semiconductor integrated circuit), a communication apparatus using the IC, a program, an operation method thereof, and a particularly effective technique.

  One of the wireless communication standards is called Bluetooth and performs short-range wireless communication using a frequency band of 2.4 GHz to 2.48 GHz. The Bluetooth standard wireless communication system is a packet communication system that transmits a predetermined amount of data with a header, and includes asynchronous communication (ACL: Asynchronous Connectionless) having a retransmission function and packet transmission at a predetermined cycle without a retransmission function. Two communication modes of synchronous communication (SCO: Synchronous Connection Oriented) for transmission are provided, and transmission and reception are performed in time division.

  In Bluetooth communication, in order to synchronize the clock between the master device and the slave device and to establish a communication connection, the period is twice as high as 3.2 kHz based on a 3.2 kHz clock signal called Bluetooth clock. Packet data is exchanged at (625 μs).

  Devices that are capable of Bluetooth communication can communicate by freely using asynchronous communication and synchronous communication. If you want to send data that requires high reliability, such as text data, use asynchronous communication. For transmission of data such as audio data that requires real-time performance, the use of synchronous communication is performed.

  As is well known, in wireless communication, the intensity of radio waves may temporarily decrease due to changes in the usage environment, and communication may become impossible, and even in Bluetooth communication, packet loss occurs under such circumstances. In the asynchronous communication of Bluetooth communication, even if there is a packet loss, the side that received the packet stores information indicating that the data has been received in the next transmission packet and transmits it. Therefore, if the information is not included in the packet received after transmission, the transmitting side determines that the packet is lost and retransmits the same data, so there is no problem. FIG. 1 shows a state of asynchronous communication in Bluetooth communication.

  As shown in FIG. 1, when the packet transmitted by the Bluetooth communication device A for the third time, the fifth, sixth, and eighth times does not reach the communication device B, the communication device A receives the third transmission packet for the third time. And the same data C as in the fifth time, and the same data E as the eighth time in the ninth transmission packet. The same applies when the packet transmitted by the communication device B does not reach the communication device A. For example, the packet transmitted by the communication device B for the eighth time does not reach the communication device A as shown in FIG. In this case, the communication device B retransmits the ninth transmission packet with the same data “d” as in the eighth transmission packet. Such data retransmission avoids data loss in asynchronous communication.

  On the other hand, in the case of synchronous communication, since such data is not retransmitted, data loss occurs. FIG. 2 shows a state of synchronous communication in Bluetooth communication. As shown in FIG. 2, if the packet transmitted by the communication device A for the third, fifth, and sixth times does not reach the communication device B, the data C, E, and F are lost. In the conventional synchronous communication, since the receiving device does not have a function for restoring received data, an error may occur in the received data if the state of the communication transmission path is bad. FIG. 2 shows a state in which an error has occurred in the packet transmitted by the communication device A for the eighth time. In this case, the packet transmitted by the communication device A reaches the communication device B, but the data H in the packet contains an error.

Conventionally, as a compensation technique for lost data in a packet communication system that does not have a retransmission function, for example, in an IP telephone system, a sequence number indicating the order of packets is put in the header of the packet and data divided in time series is An invention has been proposed in which a plurality of consecutive packets are overlapped and transmitted (Patent Document 1).
JP 2003-163714 A

  However, in the Bluetooth standard, in order to guarantee communication between communication devices provided by different manufacturers, the specification of the packet configuration including the header is strictly determined, and the specification different from the standard cannot be given. The header of the Bluetooth standard transmission packet is not provided with an area for storing information such as a sequence number indicating the packet order. Therefore, data compensation as in the prior invention cannot be performed. Further, the invention of the prior application is a system in which the same data is duplicated and transmitted in a plurality of consecutive packets, and therefore the data transmission efficiency is poor. In addition, there is a problem that it is not suitable for transmitting a large amount of data such as voice and moving image transmission in a short time.

  An object of the present invention is to provide a communication control technique and a radio that can improve the reliability of communication by evaluating the reliability of received data in synchronous communication that does not have a retransmission function and is packet communication such as Bluetooth communication. It is to provide a communication device.

  Another object of the present invention is to evaluate the reliability of received data when a voice communication function or a moving image communication function is used in a synchronous communication mode that is packet communication such as Bluetooth communication and does not have a retransmission function. Provided is a communication control technique and a radio communication apparatus capable of improving communication quality by interpolating data to prevent deterioration of audio and video quality reproduced on the receiving side when reliability is low. There is.

  Furthermore, another object of the present invention is to evaluate the reliability of received data without greatly adding hardware in synchronous communication that does not have a retransmission function and is packet communication such as Bluetooth communication. An object of the present invention is to provide a communication control technique and a wireless communication apparatus that can improve reliability.

Furthermore, another object of the present invention is to guarantee the interoperability between communication devices of the same standard to which the present invention is not applied in synchronous communication that is packet communication such as Bluetooth communication and does not have a retransmission function. An object of the present invention is to provide a communication control technique and a wireless communication apparatus that can improve the reliability of communication by evaluating the reliability of received data.
The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

Outlines of representative ones of the inventions disclosed in the present application will be described as follows.
That is, the present invention determines the initial value of the data reliability based on the type of the received packet in the packet communication such as Bluetooth communication and does not have the retransmission function, and then in the wireless communication device Using the RSSI (Received Signal Strength Display) function that is generally used and the carrier sense function that monitors the transmission path, data reliability is obtained using the detection value obtained by the RSSI function and the detection value obtained by the carrier sense function. The initial value of the degree is corrected downward to be an evaluation value of the reliability of the received data. Furthermore, in the case of voice communication or moving image communication, if it is determined from the evaluation value of the reliability of the received data that the reliability is lower than a certain level (threshold), interpolation is performed with the already received data. It is what you do.

  Here, the RSSI function is a function that detects and outputs the received signal strength, and is proportional to the received power. If the transmission path is long or there is a communication obstacle that blocks radio waves in the middle of the transmission path, the RSSI value is Lower. The carrier sense function is a function for detecting whether or not another device is transmitting a radio signal, and can determine the presence or absence of an interference radio wave in the use frequency band. In general, it can be said that there is a high possibility that a packet error will occur in the transmission path when the reception intensity is low or there is an interfering radio wave.

  According to the above-described means, it is possible to evaluate the reliability of data received in synchronous communication without a retransmission function without providing a new communication error detection function, thereby improving communication reliability. Communication quality can be improved by data interpolation.

The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.
That is, according to the present invention, it is possible to improve the reliability of communication by evaluating the reliability of received data in synchronous communication that is packet communication such as Bluetooth communication and does not have a retransmission function.

Preferred embodiments of the present invention will be described below with reference to the drawings.
The most suitable wireless communication apparatus to which the present invention is applied is a wireless communication apparatus having a Bluetooth communication function. As a specific example of a wireless communication device having a Bluetooth communication function, for example, a wireless headphone that receives and reproduces audio data from an audio player or a head that enables a hands-free call by performing voice communication with a mobile phone There is a set.

  The Bluetooth standard is a standard that guarantees mutual connection even when the Bluetooth communication device built in each of the mobile phone and the headset or the mobile phone and the headset is provided by different vendors. If the Bluetooth communication device built into each of the mobile phone and the headset has a unique function that is out of the Bluetooth standard (protocol), they cannot be connected to each other. Such a property that communication devices that communicate with each other according to a predetermined standard cannot be connected to each other when having a unique function that is out of the predetermined standard is called interoperability.

  A mobile phone is provided with a plurality of functions such as a function for performing cellular wide-area wireless communication such as CDMA and GSM with another mobile phone, a display function such as a liquid crystal panel, and an input operation function using a numeric keypad. In this specification, among these functions, an IC (semiconductor integrated circuit) that supports Bluetooth communication or a plurality of ICs and electronic components are mounted on an insulating substrate or in a ceramic package so as to have a Bluetooth communication function. An electronic device such as a module is referred to as a Bluetooth communication device.

FIG. 3 shows a configuration of a first embodiment of a Bluetooth communication device having a communication function according to the Bluetooth standard.
As shown in FIG. 3, the Bluetooth communication device is roughly divided into a communication execution unit 110 called a controller that transmits and receives data via an antenna ANT and a control unit 120 called a host that controls the communication execution unit. The communication execution unit 110 and the control unit 120 are configured to exchange data and commands according to a protocol defined by the Bluetooth standard called HCI (host control interface). The communication execution unit 110 and the control unit 120 may be configured as separate semiconductor integrated circuits, or may be configured as a semiconductor integrated circuit on one semiconductor chip as described later (FIG. 11).

  The communication execution unit 110 includes a physical layer (wireless layer) 111 serving as a high-frequency signal processing unit including an up-conversion function, a modulation function, an amplification function, a reception signal amplification function, a demodulation function, a down-conversion function, and the like. A link controller 112 that processes data transmitted / received by the layer 111 according to a Bluetooth communication protocol, establishes a communication connection state with a communication partner device, performs packet analysis, decryption, reconstruction, and the like; An HCI interface unit 113 that exchanges signals between the controller 112 and the control unit 120, a link manager 114 that manages link control between the physical layer 111 and the link controller 112, and the like.

  In the physical layer 111, an RSSI function for detecting and outputting a received signal strength and a carrier sense function for detecting whether or not another device transmits a radio signal are provided. In the Bluetooth device of the present embodiment, the reliability of the received data is evaluated based on the information regarding the reception state obtained by the RSSI function and the carrier sense function in the physical layer 111 in the communication execution unit 110, and the value is expressed as a numerical value. There is provided a reliability evaluation unit 115 that informs the control unit 120 by converting (γ). In addition, the communication execution unit 110 is provided with a reference clock generation circuit that generates a 3.2 kHz reference clock signal φ0 called a Bluetooth clock that determines the period of Bluetooth communication. The link manager 114 can be composed of a microprocessor (CPU) and a memory storing its operation program.

  The control unit 120 controls the signal to the communication execution unit 110 according to the Bluetooth communication protocol, depacketizes data from the communication execution unit 110, and packetizes data to be passed to the communication execution unit 110. SD protocol unit 122 for confirming valid services of the partner device, SCE protocol unit 123 for emulating RS-232C, and a bridge between the application and the Bluetooth communication protocol, and standardized communication procedures for each device characteristic The profile unit 124, the application unit 125 that controls the entire communication device, the buffer unit 126 that temporarily holds already received data, and the like.

  The application unit 125 means a control program itself or a non-volatile memory that stores the control program. The protocol units 122 and 123 and the profile unit 124 may also refer to the control program itself, or may include a mechanism including a mechanism for reading and decoding the control program stored in the memory. In short, the separation of the protocol units 122 and 123, the profile unit 124, and the application unit 125 is convenient for easy understanding of the function of the control unit, and is not limited to such a method.

  When the control unit (host) 120 and the communication execution unit (controller) 110 are configured as separate devices as in this embodiment, generally, a device vendor (component manufacturer) develops the communication execution unit 110, A set maker develops the control unit 120. As described above, even when the communication execution unit 110 and the control unit 120 have different development entities (vendors), the communication between the communication execution unit 110 and the control unit 120 is performed using the Bluetooth standard interface called HCI as described above. The system can be easily developed by configuring it to be able to communicate.

  4 shows a configuration of a transmission packet transmitted / received between Bluetooth communication devices, and FIG. 5 shows a configuration of an HCI data packet exchanged between the control unit (host) 120 and the communication execution unit (host controller) 110. It is shown. Processing and control by link controller 112 of communication execution unit 110 for analyzing and decoding a packet configured as shown in FIG. 4 received from another communication device and reconstructing it into an HCI synchronous communication data packet configured as shown in FIG. The HCI synchronous communication data packet configured as shown in FIG. 5 received from the unit 120 is analyzed, decoded, and reconstructed into a packet configured as shown in FIG.

  In FIG. 4, the part to which the code “AC” is attached is an access code area in which a tag indicating the other party to which the packet is sent is entered, and the part to which “HEAD” is attached manages the packet type and communication link. The packet header area in which the parameters are entered, and “PL” is the payload area in which the data to be transmitted is entered. In FIG. 5, the part to which the symbol “DATA” is attached is a data area in which data to be transmitted is entered, and the part to which “CH” is attached distinguishes devices when performing data communication with a plurality of Bluetooth devices. The connection handle area where the code for distinguishing the contents, audio data, or image data to be entered, and the part with “RSV” are not yet specified by the Bluetooth standard, but are reserved in advance. The reserved area “DTL” is a data length designation area for storing information indicating the length of data in the data area DATA.

  In the Bluetooth standard, in addition to the above data packet as an HCI packet, a command packet used when issuing a command to be given from the host to the host controller, and conversely an event used when issuing a command from the host controller to the host There is a packet. Also, regarding data packets for exchanging data between the host and the host controller, downstream data packets used when sending data from the host to the host controller, and when sending data from the host controller to the host There are uplink data packets to be used.

  6A to 6C show timings of three modes defined for Bluetooth voice communication by synchronous communication (SCO). As shown in FIG. 6, in synchronous communication in Bluetooth voice communication, HV1 packet mode in which packets are alternately transmitted from the master to the slave and from the slave to the master every two slots (1.25 msec), and four slots HV2 packet mode that alternately transmits packets from master to slave and slave to master every (2.5 msec), and packet transmission from master to slave and slave to master every 6 slots (3.75 msec) There is an HV3 packet mode to be performed, and when establishing communication between two devices, it is determined in which mode communication is performed. Note that the mode can be switched by notifying that the mode is switched between the master and the slave even during communication.

  Next, encoding / decoding and error detection of each of the packets HV1, HV2, and HV3 will be described. The HV1 packet is a packet capable of error correction by a 1/3 FEC (One Third Forward Error Correction) method. In this method, as shown in FIG. 7A, encoding is performed by repeating each bit of transmission data by 3 bits on the transmission side, and decoding is performed by taking the majority of consecutive 3 bits of reception data on the reception side. .

  The HV2 packet is a packet that can be corrected by a 2/3 FEC (Two Thirds Forward Error Correction) method. In this method, as shown in FIG. 7B, a code word “y” is generated by adding a 5-bit parity bit to 10-bit transmission data “x” using a Hamming code on the transmission side, and receiving The received data is decoded using the parity bit on the side. In the (15, 10) Hamming code, 1-bit error correction and 2-bit error detection are possible. On the other hand, the HV3 packet is not encoded for error detection / correction, and the transmission data is sent to the receiving side as it is.

  Since synchronous communication does not have a retransmission function, even if it has the error detection / correction mechanism as described above, a decoding error may occur on the receiving side due to noise in the communication transmission path. For example, in the case of an HV1 packet, as shown in FIG. 7 (A), the receiving side takes the majority of 3 consecutive bits and decodes it. I understand that it is not done. In an HV2 packet using a (15, 10) Hamming code, 1-bit error correction and 2-bit error detection are possible, and therefore correct decoding is not performed when an error of 3 bits or more occurs in the communication transmission path. Further, since the HV3 packet is not encoded for error detection / correction, as shown in FIG. 7C, when an error occurs in the transmission path, the data including the error is directly sent to the receiving side. Will be sent.

  In this embodiment, in order to estimate the decoding error and the reception error as described above, the reliability evaluation unit 115 evaluates the reliability of the received data using the information obtained in the physical layer 111 of the communication unit 110. The control unit 120 is notified. Specifically, as information regarding the reception state obtained from the physical layer 111 by the device on the receiving side, there is information obtained by an RSSI function or a carrier sense function provided in the physical layer 111. In the present embodiment, the reliability of received data is evaluated using such information by the following method.

  Hereinafter, a method for calculating the reliability of received data in this embodiment will be described with reference to FIG. In the following description, the reliability of received data is represented by γ, and the greater the value of γ, the higher the reliability of the data.

  First, the communication unit 110 reads information in the header area to determine the type of received packet (step S1). Then, it is determined whether the received packet is an encoded packet. If it is not encoded, it is determined as an HV3 packet, and the initial value of the reliability γ is set to “c” (steps S2 and S6). On the other hand, when the received packet is an encoded packet, the FEC rate is checked, and when it is “1/3”, it is determined as an HV1 packet, and the initial value of the reliability γ is set to “a” (step S3). , S4). If the FEC rate is “2/3” in step S3, it is determined as an HV2 packet, and the initial value of reliability γ is set to “b” (step S5). Since different encoding schemes are adopted for each packet, the initial values a, b, and c of the data reliability γ of each packet are different, and the initial value “a” of the reliability γ of the HV1 packet is the highest. The next is the initial value “b” of the reliability γ of the HV2 packet, and the initial value “c” of the reliability γ of the HV3 packet is the lowest, that is, a> b> c.

  Next, the process proceeds to step S7, and an RSSI (received signal strength) value obtained by the RSSI function is read into the reliability evaluation unit 115, and it is determined whether the RSSI value is within a predetermined range (step S8). In a wireless communication system, there is an upper limit and a lower limit on the received signal strength for receiving a packet with no error by the receiving device, but this optimum received signal strength range depends on the performance of the device used in the system. As the RSSI value at the time of packet reception is farther from the optimum received signal strength range, the possibility of a bit error in received data increases. Therefore, if the possibility of bit errors in received data outside the optimum received signal strength range is set to “d”, “d” means the RSSI value at the time of packet reception and the upper limit value MAX or the lower limit value MIN of the optimum received signal strength range. Depends on the difference. In step S9, a value “γ−d” obtained by subtracting this bit error possibility “d” from the reliability γ of each packet set in steps S4 to S6 is set as the reliability γ after considering the RSSI value.

  Thereafter, the process proceeds to step S10, the interference wave intensity value obtained by the carrier sense function is read into the reliability evaluation unit 115, and it is determined whether or not the interference wave intensity value is equal to or higher than a predetermined level (step S11). . In general, the higher the power of the interference radio wave, the higher the possibility of a bit error in received data. Therefore, the possibility of a bit error in the received data due to the interference radio wave is set as “e”, and in step S12, the possibility of the bit error due to the interference radio wave “e” is subtracted from the reliability γ of the reception data obtained in step S9. The calculated value “γ−e” is calculated as the reliability γ after considering the interference radio wave intensity value, and is notified to the control unit 120.

  Upon receiving this reliability γ, the control unit 120 determines whether γ is lower or higher than a predetermined threshold value, and if γ is lower than the threshold value, performs interpolation of received data (steps S13 to S13). S15). Since the voice waveform is composed of the sum of sine waves whose amplitude and phase change gradually over time, when a packet with low data reliability is received in voice communication, the data of that packet has already been received. By performing the process of replacing the data with the packet with the high reliability immediately before being performed, the quality of the reproduced voice can be improved as compared with the data loss.

  As a method of notifying the control unit 120 of the data reliability γ calculated by the communication processing unit 110, a code representing the data reliability γ is output as a signal, or a memory or register storing the code representing the data reliability γ is communicated Provided on the processing unit 110 side, when the reliability is calculated, an interrupt signal is sent from the communication processing unit 110 to the control unit 120, and the control unit 120 reads the data reliability in the memory or register. There is a way. In addition, the communication processing unit 110 is provided with means for detecting a loss (missing) of a received packet to notify the control unit 120. When the control unit 120 receives a missing packet, the reliability immediately before reception has been received. It may be configured to perform processing such as interpolation with high packet data. In this specification, the term “interpolation” includes a data interpolation process when a packet is lost and a process of replacing the data with low reliability with data of a packet with high reliability.

FIG. 9 shows a configuration of a second embodiment of a Bluetooth communication device having a communication function according to the Bluetooth standard.
In the first embodiment, the reliability γ calculated by the reliability evaluation unit 115 of the communication processing unit 110 is directly notified to the control unit 120, whereas this second embodiment is shown in FIG. As described above, the reliability γ calculated by the reliability evaluation unit 115 is transferred to the HCI packet generation unit 116 in the HCI interface unit 113 and notified to the control unit 120 by the HCI packet from the HCI interface unit 113. is there.

  Specifically, the reliability γ is added to the HCI event packet having the format as shown in FIG. By configuring in this way, the reliability of received data can be notified from the communication processing unit 110 to the control unit 120 using the hardware originally possessed by the Bluetooth communication device, so that the design change can be made only by software, and development The period can be shortened and the cost can be reduced. In addition, since it is not necessary to use a standard deviating from the Bluetooth standard, it becomes easy to maintain the interoperability between the Bluetooth communication devices.

  Here, as a method of storing the reliability γ in the HCI event packet, for example, it is defined that an 8-bit event code area ECA is provided at the head of the HCI event packet, and 256 events are included in this area. Code can be stored, but there are not so many types of event codes at the moment, and there are undefined codes, so the undefined code is used to inform the decrease in reliability, and it is calculated in the subsequent parameter area There is a method for storing and notifying information specifying the parameter and length in which the reliability γ is stored in the parameter length specifying area PLA next to the event code area ECA. .

  In the Bluetooth communication standard, the event code “FF” to be entered in the event code area ECA at the head of the HCI event packet is released as a command that can be freely defined and used by the vendor. It may be defined and used as a notification command.

  Further, instead of putting the reliability γ in the HCI event packet and notifying the control unit 120, it is also possible to insert the reliability γ in the HCI data packet as shown in FIG. Is possible. When using an HCI data packet, in the HCI data packet for voice data, the next 4 bits of the connection handle area CH is a reserved area RSV whose use is not defined in the Bluetooth communication standard. The data reliability γ can be included and sent to the control unit 120. Instead of the reserved area RSV, the reliability γ of the received data may be put in the data area DATA and sent to the control unit 120.

FIG. 11 shows a more specific configuration of the Bluetooth communication device to which the embodiment is applied. In FIG. 11, blocks having the same functions as those in FIG.
In the Bluetooth communication device of this embodiment, the link controller 112 of the communication execution unit 110, the interface unit 113, the link manager 114, the reliability evaluation unit 115, the protocol units 121 to 123 of the control unit 120, and the profile unit 124 are combined into one semiconductor chip. 1 is configured as a semiconductor integrated circuit (Bluetooth communication IC) 100. The RF module 200 as a high-frequency signal processing device constituting the physical layer 111 and the flash memory 310 as the application unit 124 are connected to the Bluetooth communication IC 100 as external components, and these are mounted on a printed wiring board or the like. Thus, a communication system is configured.

  The RF module 200 includes a modulation / demodulation IC, a power amplifier (high frequency power amplifier), a filter for removing unnecessary waves, a transmission / reception changeover switch, and the like. In the Bluetooth communication IC 100 of this embodiment, the link controller 112, the link manager 114, and the reliability evaluation unit 115 are integrally configured by a dedicated logic circuit, and are shown as one block in FIG.

  Further, although not particularly limited, in the system of the present embodiment, a power supply voltage from a battery power source such as 3.3V is applied to the Bluetooth communication IC 100 and the RF module 200 such as 2.8V. A voltage regulator (DC-DC converter) 400 for converting to a power supply voltage and an external SRAM (static memory) 320 for providing a temporary storage area for data and a work area for the CPU are provided. Since the SRAM 320 is provided, previously received data can be stored, and if the reliability of the received data is low, data interpolation can be performed based on the already received data. . Since voice data does not require as much accuracy as text data, data interpolation is performed based on previously received data in voice communication using Bluetooth communication, thereby avoiding deterioration in sound quality due to voice interruptions. There is an advantage that you can.

  In the system of this embodiment, an oscillator 210 having a high frequency such as 13 MHz is connected to the RF module 200, and a clock signal φ0 necessary for the operation of the RF module 200 is generated. It is also supplied to the Bluetooth communication IC 100 and is used as a reference clock signal for the operation clock φ1 of the protocol stack unit 122. The Bluetooth communication IC 100 of this embodiment is provided with a clock pulse generator (CPG) that multiplies the clock signal φ0 from the RF module 200 to generate an operation clock φ1 of 26 MHz or 52 MHz. Similarly, the clock signal φ0 output from the RF module 200 is input to the communication execution unit 110 as a reference clock for Bluetooth communication.

  In this embodiment, since the link controller 112 is formed on a semiconductor chip separate from the RF module 200 as the physical layer 111, the timing of signals between the RF module 200 and the link controller 112 can be adjusted and level can be adjusted. An RF interface 161 is provided for matching the two.

  A cache memory 181 and a RAM 182 are connected to the CPU 171 via a first CPU bus L-bus. The cache memory 181 and the RAM 182 are connected to the second CPU bus I-bus, and a bus bridge PPBS for exchanging data between the buses is provided between the second CPU bus I-bus and the peripheral bus HPB. A DMA controller DMAC for performing DMA (direct memory access) transfer control is connected to the second CPU bus I-bus.

  In this embodiment, it can be considered that the link controller 122 of FIG. 3 is configured as firmware by a protocol processing routine and a CPU 171 that executes the protocol processing routine among application programs in the flash memory 310. The LLCA protocol unit 121 to SCE protocol unit 123 of FIG. 3 can also be regarded as being configured as firmware by the protocol processing routine and the CPU 171 that executes the protocol processing routine among the application programs in the flash memory 310.

  Further, in the Bluetooth communication device of this embodiment, the second CPU bus I-bus is provided with a bus state controller BSC for performing control such as timing adjustment of signals on the bus, and the second CPU bus I-bus is provided with the bus state controller. Data signals can be exchanged with the external system bus 330 to which the flash memory 310 is connected via the BSC.

  The peripheral bus HPB includes a timer unit TMU for various time management, serial communication interfaces SCIF1 and SCIF0 for serially inputting / outputting signals to / from an external device, an interrupt controller INTC for receiving an interrupt from the external device, an analog Peripheral circuits such as a conversion circuit DAC that performs digital, conversion, and digital / analog conversion are connected.

  Although not particularly limited, in this embodiment, the reliability of received data is notified from the communication execution unit 110 side to the control unit 120 side by an HCI packet as described in the second embodiment. Since the communication execution unit and the control unit are formed on the same chip, it is not always necessary to use the HCI packet as means for notifying the reliability of received data from the communication execution unit side to the control unit side. By using it, when developing an application program stored in the flash memory 310 on the set maker side, there is an advantage that past design assets can be used and development becomes easy.

  As described above, in the above-described embodiment, the RSSI function is obtained by using the RSSI (Received Signal Strength Display) function generally used in the wireless communication apparatus and the carrier sense function for monitoring the transmission path. Since the initial value of data reliability is adjusted downward with the detected value and the detection value obtained by the carrier sense function to make it an evaluation value of the reliability of the received data, hardware must be added significantly It is possible to improve the reliability of communication by evaluating the reliability of received data.

  Further, since it is not necessary to put extra information in the packet on the transmission side so that the reliability of the packet can be evaluated on the reception side, the interconnection between communication devices of the same standard not applying the present invention The reliability of the packet can be evaluated without degrading the performance. Furthermore, when the voice communication function and the moving image communication function in the synchronous communication mode are provided, the received data is evaluated when the reliability of the received data is evaluated and the reliability is determined to be lower than a certain level (threshold). Since the data is interpolated, it is possible to prevent the quality of audio and video reproduced on the receiving side from being lowered and to improve the communication quality.

  Furthermore, information indicating the reliability of received data is obtained by using an HCI event packet or HCI data packet supplied from a circuit that performs communication processing according to a predetermined protocol defined in the Bluetooth standard to a higher-level control device. Since the information is notified to the upper control device, the reliability of the received data can be notified to the upper control device without significantly changing the hardware or software. In addition, since a buffer memory capable of storing already received audio data is provided, it is possible to easily perform a pseudo restoration using already received data when the reliability of the received data is low. .

The invention made by the present inventor has been specifically described based on the embodiments. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Nor.
For example, in the above-described embodiment, the reliability of received data is notified to the control unit using the HCI packet. However, in the Bluetooth standard, test control that supports the test function accompanying the interface unit 113 of the communication processing unit 110 is used. Since the interface (TCI) and the TCI packet used therefor are defined, when the test processing interface (TCI) is provided in the communication processing unit 110, the reliability evaluation unit 115 is used for the TCI packet by using the test control interface. The controller may be configured to notify the control unit 120 of the reliability γ calculated in (1). Even in this way, it is possible to maintain the interoperability between the Bluetooth communication devices.

  The Bluetooth standard defines the configuration of a packet (TCI packet) between the host controller and the host host when the test control interface (TCI) is provided, but the TCI function provided on the host controller side is a hardware function. Hardware and software. Therefore, the test control circuit may be designed as a dedicated circuit, and as the test control circuit, for example, a TAP (Test Access Port) defined by the standard related to the boundary scan test determined by JTAG (Joint Test Action Group) An interface circuit called can be used.

  In the embodiment of FIG. 11, the flash memory 310 is connected to the Bluetooth communication IC as an external memory, but may be built in the Bluetooth communication IC as an internal memory. Also, a buffer memory capable of storing a predetermined amount of received data is provided on the link controller side, and an appropriate one is selected from the already received data in the HCI data packet that informs the reliability of the received data. You may make it pass to the control part side. As a result, data interpolation processing on the control unit side can be omitted, and the burden on the CPU can be reduced. Furthermore, in the above-described embodiment, communication of a packet containing audio data has been described as an example. However, the present invention can also be applied to communication of not only audio data but also image data.

  Although the present invention has been described with reference to the case where the present invention is applied to an embodiment assuming a hands-free system comprising a mobile phone and a headset, the present invention is not limited to this, and the mobile phone and the car audio are connected to the Bluetooth. Hands-free system connected by communication, transceiver using Bluetooth communication or extension telephone system, voice communication between headset and personal computer used for voice communication system (so-called Internet phone) using the Internet, portable audio such as MP3 player It can be widely used for music data communication between a device and a headset, and also for synchronous communication using packets other than Bluetooth communication.

FIG. 1 is a timing chart showing an example of asynchronous communication in Bluetooth communication. FIG. 2 is a timing chart showing an example of synchronous communication in Bluetooth communication. FIG. 3 is a block diagram showing the configuration of the first embodiment of the Bluetooth communication device to which the present invention is applied. FIG. 4 is a packet configuration diagram showing a configuration of a transmission / reception packet used for synchronous communication of Bluetooth communication. FIG. 5 is a packet configuration diagram showing a configuration of an HCI data packet exchanged between a control unit (host) and a communication execution unit (host controller) in Bluetooth communication. 6A, 6B, and 6C are timing charts showing transmission timings of three types of HV packets used for synchronous communication of Bluetooth communication. FIGS. 7A, 7B, and 7C are explanatory views showing respective encoding methods of HV1, HV2, and HV3 packets used for Bluetooth synchronous communication. FIG. 8 is a flowchart showing the calculation procedure of the reliability of the received packet in the Bluetooth communication device of the first embodiment. FIG. 9 is a block diagram showing a second embodiment of the Bluetooth communication device to which the present invention is applied. FIG. 10 is a data configuration diagram showing the configuration of an event packet as an example of an HCI packet that informs the control unit of the reliability of received data. FIG. 11 is a block diagram showing a more specific configuration example of the Bluetooth communication device to which the first embodiment is applied.

Explanation of symbols

110 Communication processing unit 111 Physical layer (wireless layer)
DESCRIPTION OF SYMBOLS 112 Link controller 113 HCI interface part 114 Link manager 115 Reliability evaluation part 120 Control part 121 LLCA protocol part 122 SD protocol part 123 SCE protocol part 124 Profile part 125 Application part 125 Buffer part

Claims (11)

  A semiconductor integrated circuit for wireless communication capable of performing synchronous communication in accordance with a protocol defined by a predetermined wireless communication standard, evaluating the reliability of received data and whether or not data interpolation is necessary or not A semiconductor integrated circuit for wireless communication, comprising a function of notifying information indicating the size of the data to a host control device in a data format of a predetermined format.   The predetermined wireless communication standard is a Bluetooth standard, the data form is an HCI event packet, and declares that the packet is a packet informing the reliability of received data in the event code area of the HCI event packet, 2. The semiconductor integrated circuit for wireless communication according to claim 1, wherein information indicating the necessity or non-necessity of the data interpolation is stored and transmitted in a parameter area subsequent to the event code area. .   Declare that the packet is a packet that informs the reliability of the received data using a code that is not defined by the Bluetooth standard in the event code area or a code that is set freely by the vendor. The semiconductor integrated circuit for wireless communication according to claim 2.   2. The semiconductor integrated circuit for wireless communication according to claim 1, wherein the predetermined wireless communication standard is a Bluetooth standard, and the data form is an HCI data packet.   5. The HCI data packet is declared and transmitted in a reserved area whose use is not defined by the Bluetooth standard, and is transmitted to declare reliability of received data. Semiconductor integrated circuit for wireless communication.   6. The semiconductor integrated circuit for wireless communication according to claim 5, wherein information indicating whether or not the data interpolation is necessary or not is stored and transmitted in a data area of the HCI data packet. Synchronous communication can be performed according to the protocol defined by the Bluetooth standard, and includes a first function, a second function for detecting received signal strength, and a third function for detecting interference wave strength. A semiconductor integrated circuit,
The first function is
(1) Initial reliability of received data determined by a predetermined encoding method for each of a plurality of communication modes for synchronous communication defined by the Bluetooth standard;
(2) RSSI (Received Signal Strength) value obtained by the function of detecting the received signal strength,
(3) Interference wave intensity value obtained by the function of detecting the interference wave intensity,
First information indicating the necessity of data interpolation or the necessity of data interpolation is generated from any one of (1) except (1) or a combination of any two or more of (1) to (3). A semiconductor integrated circuit for wireless communication, characterized by notifying a control device. A wireless communication device having a semiconductor integrated circuit for wireless communication and a host control device,
The wireless communication semiconductor integrated circuit can perform synchronous communication in accordance with a protocol defined by the Bluetooth standard, and has a first function, a second function for detecting received signal strength, and a first function for detecting interference wave strength. With three functions,
The first function is
(1) Initial reliability of received data determined by a predetermined encoding method for each of a plurality of communication modes for synchronous communication defined by the Bluetooth standard;
(2) RSSI (Received Signal Strength) value obtained by the function of detecting the received signal strength,
(3) Interference wave intensity value obtained by the function of detecting the interference wave intensity,
First information indicating the necessity of data interpolation or the necessity of data interpolation is generated from any one of (1) except (1) or a combination of any two or more of (1) to (3). To inform the control device,
The upper control device is
When the received data is audio data and the first information is information indicating the necessity of data interpolation, the first information is based on the first information or the first information is necessary for data interpolation. A wireless communication apparatus that compares the first information with a predetermined threshold value and performs data interpolation based on a comparison result when the information is information indicating the size of the data. It is possible to perform synchronous communication in accordance with the protocol defined by the Bluetooth standard, evaluate the reliability of the received data, and display information indicating the necessity or non-necessity of data interpolation in a predetermined format. A program executed by a microprocessor in a semiconductor integrated circuit for wireless communication having a function of notifying a higher-level control device in form, a function of detecting received signal strength, and a function of detecting interference wave strength,
(1) determining an initial reliability of received data determined by an encoding method set in advance for each of a plurality of communication modes for synchronous communication defined by the Bluetooth standard;
(2) determining reliability of received data from an RSSI (received signal strength) value obtained by the function of detecting the received signal strength;
(3) determining the reliability of the received data from the interference wave intensity value obtained by the function of detecting the interference wave intensity;
A program for causing the microprocessor to execute at least one of the above. A program executed by a microprocessor in a semiconductor integrated circuit for wireless communication control that processes data received by synchronous communication defined by the Bluetooth standard,
(1) a first step of determining whether or not to perform data interpolation by comparing information indicating the necessity of interpolation of received data received from the wireless layer with a predetermined threshold;
(2) a second step of performing interpolation processing on the received data determined to be subjected to data interpolation in the first step;
A program for causing the microprocessor to execute. An operation method of a wireless communication device capable of performing synchronous communication according to a protocol defined by the Bluetooth standard,
(1) determining an initial reliability of received data determined by an encoding method set in advance for each of a plurality of communication modes for synchronous communication defined by the Bluetooth standard;
(2) determining reliability of received data from an RSSI (received signal strength) value obtained by the function of detecting the received signal strength;
(3) determining the reliability of the received data from the interference wave intensity value obtained by the function of detecting the interference wave intensity;
The presence or absence of the necessity of data interpolation or the magnitude of necessity is determined from any one of (1) except (1) or a combination of any two or more of (1) to (3) How it works.

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