HK1059688B - A method of transmitting information between two units each provided with means for sending and/or receiving signals - Google Patents

Description

Method for transmitting information between two units each having means for transmitting and/or receiving signals

Technical Field

The invention relates to a method for transmitting information between at least two units consisting of two computer stations, or two personal portable devices, or a computer station and a personal portable device. For example, the portable device is a personal watch. To implement the method, the portable device, such as a watch, and the computer station each comprise means for transmitting and/or receiving signals, which are active in a transmitting and receiving mode, respectively. The transmitted short range radio frequency signal includes at least one information frame modulated on a carrier wave selected from a large number of carrier waves available in the computer station and/or in the watch. The information in the frame relates to data stored in a memory of a watch, for example, or data transmitted from the memory to a computer station. The information may also relate to commands to perform operations or requests to identify the sending source.

Background

The data transmitted from the memory or stored in the memory is preferably data having a log function. When the log function is activated, it is possible to consult the previously stored data records under different menus, by means of the activation key of the watch. The different menus of the log function relate to notes, an address book, a log, and the transmission of data by radio frequency signals and parameters. Wherein the log function menu relates to a data transfer mode. In the selected transmission mode, data is transmitted from the watch memory to the computer station or received from the computer station. When this menu is selected, it is in principle not possible to use another logging function of the watch before the transmission state is terminated.

The transmission of data between a computer station and an electronic watch by means of short-range radio-frequency signals is known in the art. For example, european patent application No. EP0957589 describes a communication system connecting first and second units. Each of said units comprises means for transmitting and/or receiving short range radio frequency signals, said short range radio frequency signals being used for bi-directional data transmission. Preferably, said first unit is a personal electronic watch and said second unit is a computer station. Said electronic watch with means for transmitting and/or receiving signals must be in a certain coverage area of the computer station in order to exchange data.

Once communication is established with said computer station, the transmitting and/or receiving means of the watch must be active at least between each cycle of transmitting and/or receiving radio-frequency signals. The data transmitted is preferably data with a logging function. The data is transmitted in packet information, and each packet information in the information frame is modulated on a high frequency carrier. The length of each transmission packet depends on the size of a non-volatile memory page in the watch. All information must be transmitted by sending a large number of information frames.

In the above-mentioned patent application, each of a large number of computer stations is able to communicate with a corresponding personal watch in the same coverage area. For this purpose, the transmission of data signals between each station and a respective personal watch uses a high-frequency carrier that is different from the high-frequency carrier used for the transmission between the other stations and the respective personal watches. The data signal modulated carrier wave is selected at the computer station, for example, to function as a collision avoidance protocol, as is known in the art, so as not to interfere with data transmissions between other stations and other watches.

In application EP0957589, a major drawback is that there is no provision to limit the power consumption of the watch during the transmission of the data of the bidirectional logging function. Since the electronic watch is a small instrument powered by a low-power energy source, it is necessary to optimise all the times of transmission of the necessary data transmitted between the computing station and the watch. This optimization necessarily limits the operating time of the transmitting and/or receiving means of the watch, which consumes a great deal of energy.

Disclosure of Invention

It is an object of the present invention to overcome the drawbacks of the prior art by providing a method for wireless information transmission between two units, such as a computer station and a watch, which reduces the time for transmitting the entire data. In particular, the activation time of at least one of the units, such as the transmitting and/or receiving means of the watch, is reduced. The reduction of the transmission time depends on the transmission quality and the power supply state of each unit. Therefore, it is necessary to be able to dynamically vary the length of a portion of each information frame as a function of the quality of the transmission.

To this end, the invention provides a method as cited above for the wireless transmission of information between at least two units, two computer stations or two personal portable devices or a personal portable device and a computer station, said method being characterized in that it comprises the following steps:

-transmitting an information frame from one unit to another, said information frame being modulated on a selected carrier and comprising a synchronization field, said synchronization field consisting of a specific number of bytes of the same value and an information packet;

-counting bytes in the synchronization field of the received frame, and

-comparing the counted number of bytes with a specific threshold value to send an indication to correct the number of bytes in the synchronization field of the next frame to be received.

The method of information transfer of the present invention has the advantage of saving time in transferring information between the first and second units by dynamically changing the size of the synchronization field. All data transmissions are monitored, thereby reducing transmission errors. The transmission protocol used enables more information to be transmitted in less time. If the transmission quality is good, the length of the synchronization field can be reduced, and conversely, if the transmission quality is degraded, the length of the synchronization field is adaptively changed so that all data can be transmitted from one unit to another without hindrance.

If the length of the synchronization field is not changed, the length of the synchronization field must be large enough to guarantee information transmission in the worst environment. While a fixed length is disadvantageous for the time to transmit information between two units.

Since one of the units is preferably a personal electronic watch, for example, the length of the synchronization field depends on the time taken for the watch to switch between the transmission and reception modes of the radio frequency signals. Moreover, said switching time depends on the value of the voltage supplied by the battery to the electronic components of the watch. It is clear that the length of the synchronization fields increases if the voltage drops.

Before extracting information from each frame, each unit should count at least a minimum number of sync bytes of the same value, such as at least three sync bytes, and append another two bytes of the same value as a security consideration. When the unit locks onto a selected high frequency carrier for the radio frequency signal, the number of bytes in the receive synchronization field is counted.

In a preferred embodiment, the unit consisting of the computer station is able to increase or decrease the length of data transmitted to a portable device such as the watch. The length is defined by the length of the page of stored data in a non-volatile memory in the watch, for example 64 bytes. If a transmission error is detected, it is necessary to retransmit information frames that have not been received. Therefore, the more transmission errors the transmission station detects, the longer it takes to transmit all the data. For the reasons described above, the computer station may adjust the length of the transmitted data to reduce these errors. Therefore, an optimal transmission quality function must be found.

In a preferred embodiment, the computer station transmits formatted data frames, which can be stored in a non-volatile memory of a portable device, such as a watch. The read and write addresses of the memory are transmitted in information frames of the computer station. This eliminates the need to query the memory address of the read and write data when the data management unit of the watch receives the information frame. This saves time reading or writing the memory.

Drawings

The above-mentioned objects, advantages and features of the method for wireless transmission of information between two units will become more apparent in the following non-restrictive description of the invention with reference to the accompanying drawings, in which:

FIG. 1 shows a device comprising a computer station and a personal watch for carrying out the method of wireless transmission of information according to the invention;

FIG. 2 is a block diagram of the various electronic units of the information transmission device according to the invention of FIG. 1;

FIG. 3 is a block timing diagram of the frames of information transmitted between the computing station and the personal watch in the transmission method according to the invention;

FIG. 4 shows an information frame of a radio frequency signal modulated on a high frequency carrier in the transmission method according to the invention;

FIG. 5 is a general flow chart illustrating the steps performed in a computer station in the transmission method according to the invention;

FIG. 6 is a flow chart illustrating the steps performed in the computer station to search for an idle carrier or transmission channel in the transmission method according to the invention;

FIG. 7 shows an information transmission flow diagram for communicating information from a computer station according to the transmission method of the invention;

figure 8 shows a rough flow chart of the steps carried out in the watch in the transmission method according to the invention;

fig. 9 is a flow chart of the steps performed in the watch to search for a free carrier or transmission channel in the transmission method according to the invention;

FIG. 10 is a flow chart of the information transmission steps for communicating information from the watch according to the transmission method of the invention;

FIG. 11 is a flow chart of the information transmission steps of the transmission of information from the watch according to the transmission method of the invention;

Detailed Description

The following description relates to a method for wireless transmission of information between two units, each unit having means for transmitting and/or receiving signals. For example, the signal is a short range radio frequency signal. The unit comprises a computer station and an electronic watch. Likewise, it is also possible to envisage the transmission of information between two computer stations or two portable devices, such as two watches, by means of the information transmission method according to the invention.

Since various types of information can be transmitted by the method according to the invention, the remainder of the description relates mainly to the transmission of information about the logging function between the electronic watch and the computer station, such as the transmission of data about the menus of the logging function, such as diaries, addresses, logging data and parameters.

In the example shown in fig. 1, the device for implementing the method for wireless transmission of information consists of two units, namely an electronic watch 1 and a computer station 20. The computer station 20 mainly comprises a keyboard 23, a mouse 22 and a screen 21 which can display data of all the logging functions. For ease of use, the log of individuals appearing on the screen 21 of the computer station may be a copy of a conventional desktop calendar. In principle the log will automatically open once the user password is entered. The keyboard 23 or mouse 22 may be used to move a pointer marking a cursor or mark at the edge of the log to open the log on the screen. Once a type of log page is selected, such as by a corresponding flag, the corresponding page in the log opens on the screen and shows all the fields stored in memory. For example, each information field may include 63 alphanumeric characters.

The computer station 20 further comprises a peripheral unit 24, said peripheral unit 24 being connected to an input of the computer station by a USB or another type of cable 25. Unit 24 includes a means for transmitting and/or receiving short-range radio frequency signals by computer station 20 via antenna 26. It is clear that in a different embodiment the transmitting and/or receiving means of a computer station may equally be integrated into the host part of the station. The watch 1 also comprises means for transmitting and/or receiving short-range radio-frequency signals, said transmission and/or reception being carried out through the antenna 2 and the information being transmitted bidirectionally within a coverage area of the computer station. Two units with transmitting and/or receiving means are capable of implementing the method of transmitting information according to the invention, as will be further explained below with reference to fig. 3-11.

In the embodiment shown in fig. 1, the wristwatch 1 shown is an analogue watch with a dial 8, hands 7 indicating the time, a clock movement in the case 3 located in the lower part of the dial 8, two liquid crystal matrix displays 5 for displaying specific diary function information, control keys 4 on the inner surface of the glass and a control button 9 on the case. A battery, not shown in the figures, in the case 3 supplies the electronic components of the watch. The control keys 4 are capacitive sensors that can be individually activated by the user's finger placed in a specific area to activate the sensors. A watch with a digital time display and control buttons on the watch case to activate the various functions of the watch is also envisaged.

Fig. 2 shows a block diagram of the various units of a personal watch 1 and a computer station 20 implementing the method of bi-directional transmission of information according to the invention. The watch 1 comprises microprocessor means 14 programmed to manage the watch's logging functions. The microprocessor means 14 also comprise a module connected to the time axis to control the display of the time of the hands 7 on the dial 8. An oscillating stage is connected to a quartz crystal 10, said oscillating stage being contained in a microprocessor device 14 to time the various operations of the watch. The oscillator frequency was 32.768 kHz.

The microprocessor of the device 14 may be an 8-bit PUNCH microprocessor, such as the microprocessor produced by the company EM michroelectric-Marin, switzerland. Once the logging function has been activated by pressing the control button, the control key 4 is operable to input signals to the microprocessor means 14, the signals input from the key 4 relating in particular to menu selection of the logging function and editing of data stored in the non-volatile EEPROM 11. If the transmission mode is activated by one of the 4 keys, it is possible to browse all stored or edited data or parameters on the liquid crystal display or on the display 5.

The microprocessor means 14 are connected to a data management unit 12, said data management unit 12 being coupled to the transmitting and/or receiving means, managing the transmission or reception of all information from or to the computer station. The transmitting and/or receiving means of the watch 1 comprise an RF module 13 and an antenna 2, which are not explained in detail here, since these background techniques are well known in the art.

When the transmission mode is selected, the data management unit 12 blocks the other logging functions of the watch and, independently of the microprocessor means 14, the management unit is able to read directly the non-volatile memory 11 or write the received data directly to the non-volatile memory 11. The management unit 12 is clocked by a clock signal from a clock oscillator. It is therefore advantageous to use the clock oscillator frequency to modulate information onto a selected high frequency carrier for bi-directional information transmission (data rate 32768 baud).

For the transmission of information relating to the logging function, the computer station 20 comprises control means 31 connected to the storage means 30, said control means running a data management program. The control means 31 enable all mouse or keyboard operations to be seen on the screen of the computer station 20. The computer station 20 further comprises a peripheral unit 24, said peripheral unit 24 comprising means for transmitting and/or receiving radio frequency signals and mainly consisting of an RF module 27 and an antenna 26. This converts the signals from the device 31 or the RF module 27 and the USB interface 29 of the host part of the computer station 20 is connected to the USB interface 28 of the peripheral unit via the cable 25.

To complete communication with a personal watch, computer station 20 selects at least one of the 5 available channels, typically with the least interference. The watch must be in the coverage area of the computer station and select a transmission mode to respond to the personal call. Of course, the computer station can only respond if the watch has locked onto the transmission channel selected by the computer station and has successfully recognized its identification number (see below).

Each transmission channel corresponds to a particular high frequency carrier, for example at approximately 434 MHz. For bi-directional transmission of data, the synchronization signal should be modulated on a selected carrier. This work is managed by the computer station to save the various work performed by the watch and thus save power.

The advantages of the transmission method according to the invention are explained in more detail below with reference to fig. 3-11. The transmitting and/or receiving means in each unit are alternately switched to a transmitting mode and a receiving mode. The information frames modulated on a selected carrier are alternately transmitted from each cell as will be described first with reference to fig. 3 and 4.

Since the watch includes a non-volatile EEPROM, data from memory is sent or received to the memory page unit, and the default value of the data size in each frame is 64 bytes. Also, the size of the data transmitted may be set by the computer station to 32, 64, 128 or 256 bytes. The transmitting and/or receiving means of each unit must therefore be switched alternately to a transmitting mode and a receiving mode until all information has been transmitted. Of course, it is advantageous to transmit the information frame with the largest possible data length, but an optimal length can be found to avoid retransmitting the data frame after the receiving unit detects an error.

First, the computer station must attempt to contact the personal watch with which it wishes to communicate. To this end, the computer station selects one transmission channel from the currently available 5 transmission channels. The information modulated on the selected carrier includes synchronization information necessary to identify the data transmitted by the transmission method according to the invention.

In the first phase of the association, the computer station transmits a long string of sync bytes of the same value, said byte having a duration of 2.7 seconds, said sync bytes having a hexadecimal value of 81 and a binary representation of 10000001 in order not to confuse this value with noise. And this makes it possible to find the beginning of the sync byte. Since the frequency of the information modulated on the carrier is 32.768kHz, more than 11000 sync bytes are identical. Synchronizing time t_LThe watch must be coupled to scan the 5 transmission channels in question to lock the transmission channel selected by the computer for the time reserved. And time t_LAlso considering the remaining intervals of the transmitting and/or receiving means of the watch, it can be set to 2.5 seconds for saving power. To find a transport channel, the watch must be able to count the sync bytes when scanning the 5 transport channels currently available.

As shown in fig. 3, in the transmission mode of the computer station, the long series of sync bytes is directly followed by a first information frame 40 and comprises a variable length sync field 41, an information packet 42 and at least two padding bytes 43. The padding bytes are mainly used to switch the transmitting and/or receiving device in the transmitting and receiving mode. The value of the padding bytes may be set to a hexadecimal value of 00 to avoid collision with the data in the information packet 42 and the sync bytes.

If the watch can lock onto the transmission channel selected by the computer station during a long string of sync bytes or during the sync field of the first frame. The watch responds to the computer station with a second information frame after switching its transmitting and/or receiving means. The alternating transmission of information frames between the two units continues in this manner until all the information is transmitted. This may take several minutes to transmit all the information, which is related to the data transmission quality.

The worst case scenario for assuming a transition from transmit to receive mode in each unit is the time t for switching the transmitting and/or receiving means_RFLess than 20 ms. Switching in a watch is slower than in a computer station, because the watch is battery powered, while the computer station is connected to a mains power supply. The switching speed is therefore dependent on the power supply.

Note that the computer station transmits a long string of sync bytes followed by the first information frame many times until the user reacts and switches his watch to transmit mode in response to receipt of the first frame. The gap between each long burst of sync bytes and the first frame repetition is about 130 ms. A maximum waiting time for a response from the watch may be set to 45 seconds.

An advantage of a method according to the invention is that the length of the synchronization field 41 can be changed dynamically, depending on the speed of the RF handover and the transmission quality. For this purpose, the number of sync bytes is counted by a counter in a data management unit in the watch or by a data management program of a control device in the computer station upon reception of the information frame 40. It must be possible to count at least three sync bytes and two more safety bytes in each frame. If the number of sync bytes counted is greater than the minimum of 5 sync bytes, an indication is sent to the sender to reduce the length of the sync field by at least one byte. On the other hand, if the number of sync bytes counted is less than the minimum of 5 sync bytes, an indication is sent to the transmitter to increase the length of at least one sync field, preferably three bytes. If no response is received, the same request indicates that the sync byte string is too short.

Note that at the beginning of an attempt to establish contact between the computer station and the watch, the number of bytes in the synchronization field 41 in the information frame 40 may be set to 25 bytes, for example for security reasons.

The indication that the synchronization field length is variable is placed at the header 44 of the information packet 42 of each information frame 40. The packet 42 includes, following the header 44, a payload information field 45 and a Cyclic Redundancy Check (CRC) field 46. The CRC code is well known in the art and is initially used to check for transmission errors of previous information. If a transmission error occurs, the transmitting unit should retransmit the information frame to the receiving unit.

In the header 44, which consists of three bytes, the first byte comprises 4 control bits 47, three code bits 48 relating to the type of information transmission, and an indication 49 relating to the length of the received synchronization field. The last two bytes of the header relate to the last two bytes of the identification number of the watch. Note that the 4 control bits 47 should have the opposite value to the three code bits 48 and the indication 49 indicates that no errors were detected. Indicating 49 a value of 1 if the received synchronization field 41 is too small and indicating 49 a value of 0 if the received synchronization field 41 is too large.

If the computer station does not know the identification number of the personal watch, the first frame transmitted by said station comprises a universal number, such as 0000 in 16. When the watch is locked to a transmission channel selected by the computing station, a frame including its identification number is sent to the computer station. So that the identification number of a new personal watch is stored in the memory of the computer station. In the above-described case, the anti-collision principle is used if a large number of computer stations in a coverage area attempt to communicate with the corresponding watch. Accordingly, each table can only respond to a computer station after recognizing its own identification number. The selected transmission channels, each of which contacts a computer station and a watch, are different, thereby preventing difficulties in the transmission of information.

The following table defines the various types of information codes 48 that are transmitted from one unit to another. The first table I relates to the information code words sent from the computer station to the watch and the second table II relates to the information code words sent from the watch to the computer station.

TABLE I

Code word	Name (R)	Description of the invention
			100	Loading	Data transmitted to watch
101	Downloading	Transmitting request from watch
			110	Continue reading	FromFurther data request from watch
111	Identification number	Identification number request from watch
			111	Data length	Data unit number of each data field
000	End up	End of transmission

TABLE II

Code word	Name (R)	Description of the invention
			001	Downloading data	Data to computer station
101	Confirmation	Confirming correct receipt
			110	No confirmation	Announcing erroneous reception
111	Identification number	Transmitting back the identification number to the watch
			000	End up	End of transmission

When communicating between the computer station and the personal electronic watch, all frames of information include a header, and the header defines the type of information transmitted, as defined in the above table. In particular, the type of data transmitted can be selected or programmed in the computer station and the synchronization of the transmission from the computer station to the watch (read/write), the synchronization of the transmission from the watch to the computer station (read) or the synchronization of the transfer of the rewriting from the computer station to the watch (write).

Since it is the computer station that manages the data transmission involving the non-volatile memory from the watch, said computer station transmits the memory address directly to the watch in a radio frequency signal. Therefore, when the watch receives the radio frequency signal, the memory address can be directly pointed to a specific memory position through the data management unit of the watch. This operation can be done in the watch, while only the memory address in the radio frequency signal sent from the computer station needs to be formatted in order to read or write data from the memory of the watch, which reduces the power consumption of the watch battery. This data can be processed in the data management unit to a frequency below 40 kHz. Previously, a more complex management unit had to be present to process the received signals. The clock frequency of the management unit is approximately 512kHz and the processing is performed without information relating to memory addresses.

In a first step of the information transmission method, the data of page 0 of the static area of the EEPROM are sent out. In this way, the computer station is able to determine the position of the last data item of the dynamic zone of the watch and the various parameters. The empty region pointer stored in a static region of memory defines a valid number of pages of memory data to be transmitted.

Once the various parameters stored in the memory of the watch are obtained, in particular in said page 0, it is possible to read data from the memory. In this case, the computer station transmits a frame 40 in which the code 101 (download) is defined. Following this header, the packet 42 includes a three byte write address field, a one byte read command field, and a CRC field. The watch responds by transmitting, after having opened the transmitting and/or receiving means of the watch, a download data message to the computer station, said download data message being the code 001 (download data) in the header 44 of the packet 42 of the response frame 40. The information packet following the response header comprises an information field giving the number of data items sent and a CRC field.

After the read request frame, the computer station sends a frame with a header 44, said header 44 containing a code 110 (continue read) requiring a continue read. If so, only a read command is sent to the watch to continue reading memory data, since the pointer inside the watch is incremented by 1 and no reference is made to the contents of the page. As long as no problem occurs during the transfer, the watch sends a response frame with a code 001 in the header.

At the end of the message transmission, a message frame ending with the transmission code word 000 (end) is sent from the computer station to the watch, and an acknowledgement is sent by the watch to the computer station. From there, the transmitting and/or receiving means of the watch can be switched off and the other logging functions can be reused.

Assuming that data from the computer station is to be written to memory, the initial information frame sent by the computer station includes the code 100 (load) to load the data into the watch. During the writing of the data from the computer station to the memory, the watch sends to the computer an information frame 40 carrying the code 010 (acknowledged) if the watch correctly received said transmission and the code 011 (unacknowledged) if an error occurred during the transmission. In the latter case, the computer station transmits the same information frame until the watch transmits the code 010 to acknowledge its reception.

At the end of the transmission of the information, as previously described, an information frame ending with the transmission code word 000 (end) is sent from the computer station to the watch and from the watch to interrupt the operation of the transmitting and/or receiving means of the watch.

If the computer station records a large number of transmission errors, the length of the data field may be reduced, for example from 64 bytes to 32 bytes, as described above. In this case, the computer station sends an information frame with a code 111 (data length) to specify the length of the data field of the watch.

The various operations of the method of wireless transmission of information from the computer station to the watch and from the watch to the computer station will now be described with reference to figures 5 to 11. In these figures, the operation of the function is described by rectangles. The hexagon describes the operation of the function under supervision of an effective time delay. Diamonds describe the conditions. The rectangle with the corners removed describes the information appearing on the display device. Finally, a rectangle with two lines on the side describes the execution of a subroutine.

Fig. 5 is a schematic flow chart showing steps performed in a computer station for transmitting information. For communication, the transmitting and/or receiving means of the computer station are activated in step 60. After step 60, a contact search time, for example 45 seconds, is loaded at step 61. A search for a free transport channel may be made at step 62. After selecting an idle transmission channel, the computer station may communicate at step 63. The watch may not respond to the computer station at step 63. In this case, the contact search is resumed, and if the prescribed time (about 45 seconds) has not expired, the channel search is resumed in step 62.

The connection may be interrupted at any time during communication with the computer station. The contact is resumed in step 64. The time for re-contacting may be, for example, about 30 seconds, which is usually less than the contact search time, since it is not necessary to give the user the time for switching his watch to the transfer mode.

When all information is exchanged between the computer station and the watch, the computer station sends the end of a transmission frame to the watch and deactivates said transmitting and/or receiving means in step 65, after which it returns to the idle mode in step 66.

The "no link" output corresponds to "search time expired", i.e. at the end of 45 seconds or 30 seconds, if there is no free channel, the channel with the least interference is used anyway.

Fig. 6 shows a step 62 of searching for a free channel from the computer station.

Step 70 checks as a function of the set search time whether the search time has expired, for example 45 seconds. If the search time has expired, there is no link to communicate with the personal watch within the coverage area of the computer station and the transmitting and/or receiving means of the computer station are deactivated. If the search time has not expired, the number of available channels is set to 5 in step 71 and a channel is selected in step 72. To select a channel, a Received Signal Strength Indication (RSSI) is measured at step 73. After the RSSI is measured, the number of channels to be searched is decremented by 1 at step 74.

It is checked in step 75 whether the number of channels is 0, and if it is 0, it means that all channels have been searched. If not 0, the algorithm returns to step 72. If the channel number is 0 after subtracting 1 at step 75, there is a step 76 to restore the channel number to 5.

The measured RSSI of the first of the 5 channels is compared to a threshold for a grant. If the measured RSSI is below said threshold, i.e. a good transmission quality is required, the transmission channel is selected for communication with the watch. Otherwise, it is checked in step 78 whether the channel is the last of 5 channels, the RSSI of which has been compared with the threshold of RSSI in step 77. If so, a channel of lowest RSSI is selected as the radio frequency transmission channel at step 80. On the other hand, if it is not the last of the 5 channels, the number of channels is decremented by 1 in step 79. The RSSI measurement for the new channel selected after step 79 is compared to an RSSI threshold in step 77, and the comparison in step 77 is completed until the last of the 5 channels has been processed in this manner. Note that the test order for the 5 channels in the search for a transmission channel is random in case all computer stations always select the same channel.

Once the transmission channel is selected for transmitting information, the computer station enters a communication mode. The various steps of the communication mode 63 of the computer station are explained in connection with fig. 7.

After the transmission channel has been selected, the transmitting and/or receiving means of the computer station switch to the transmission mode Tx in step 85. An indication of the synchronization field length of the frame received by the computer station is set at step 86. At the start of the contact search, the computer station transmits a long string of sync bytes followed by an information frame at step 87. In step 88 an information frame is sent with a synchronization field, the number of bytes in the synchronization field depending on the value of the synchronization counter, and then in step 89 the information packet is sent with padding bytes in step 90.

When said padding bytes have been transmitted, the transmitting and/or receiving means of the computer station switch to a reception mode Rx, step 91. In step 92, synchronization of a response frame from one watch is awaited. At step 93, the computer station receives the sync field of the frame sent by the watch to contact, and a counter at the computer station counts the number of bytes in the sync field of the received frame. The counting of the number of bytes in the received synchronization field is done in step 94 and the computer station receives the header of the frame from the watch in step 95, including an indication to modify the synchronization field of the next frame sent from the computer. If the indication is 0, the next synchronization field sent from the computer should contain more bytes and if 1, less bytes. This allows the synchronization domain to change dynamically, which is an advantage of the method according to the invention.

At step 96, a valid check is performed involving the receipt of the header with the identification number of the responding watch. If the received header with the identification number is correct, the synchronization counter of the computer station is updated in step 97 as a function of the synchronization indication in the received frame. On the other hand, if the received header with the identification number is erroneous, the next step moves to step 104 to automatically increment the synchronization calculator of the computer station by 1. The same applies if the watch does not respond within the synchronization wait period in step 92. In step 105, the indication in the header of the next information packet sent by the computer station is set to 1 to require a long synchronization field for the watch. After step 105, a transmission error counter should be decremented by 1 in step 101.

After updating the calculator in step 97, the computer station receives in step 98 payload information from an information packet ending with a CRC code. The CRC code is checked in step 99. If the CRC code is correct, the next step is to clear a transmission error counter and a CRC error counter at step 106. On the other hand, if the CRC code is not correct, the CRC error counter is decremented by 1 in step 100 and the transmission error counter is incremented by 1 in step 101.

The transmission error counter is checked in step 102. If the number of transmission errors counted is less than a predetermined value, for example less than 3, the next step is to step 108, where the CRC code error counter is checked. On the other hand, if the number of transmission errors counted is greater than a planned set value, the next step is to step 103, in which a check is completed concerning the interrogated watch. If the watch is seen during transmission, the error considered relates to a temporary loss of connection to the watch. On the other hand, if the watch has not been seen, the contact search should be continued.

After step 106, in which the error counter is cleared, the next step is step 107, in which the value of a counter is decremented, said counter being used to count the transmitted data frames of reduced length. If the length of the data frame to be transmitted is a reduced length, the reduced length data frame is theoretically counted, for example 10 frames, before trying to transmit another larger data frame. After the number of counters counting the data frames of reduced length is decreased, the number of errors counted by the CRC error counter is checked in step 108. If the number of errors counted by the CRC error counter is greater than the planned maximum value, e.g. greater than 3, the next step is to step 113 to check the length of the transmitted data frame. On the other hand, if the number of errors counted by the CRC error counter is less than the maximum value set on schedule, the next step is to step 109 to check the counter for the number of transmitted reduced length data frames.

In step 109, if the reduced length data frame counter indicates 0, this means that all reduced length data frames have been sent out. If so, the next step is to check the length of the current data frame, step 110. On the other hand, if the reduced length data frame counter indicates a value other than 0, the next step proceeds to step 117 for switching the transmitting and/or receiving apparatus to the transmission mode Tx. Following the step 117 is a step 88 to start the transmission of a new data frame to the watch.

If the length of the current information field, i.e. the data length, is a maximum value, e.g. 256 bytes, in step 110, the next step is to step 117 for switching the transmitting and/or receiving means to the transmit mode Tx (see above). On the other hand, if the length of the current information field is not yet at the maximum value, the length is increased in step 111, after which the counter for the frame with the decreased length is loaded in step 112. In a step 117 following step 112, the transmitting and/or receiving means of the computer station switch to a transmitting mode.

The length of the transmission data is checked in step 113. If the length of the transmission data is at a minimum, the next step is to step 117 for switching the transmitting and/or receiving means of the computer station to the transmission mode Tx (see above). On the other hand, if the length of the transmission data is not the minimum value, the CRC error counter is cleared at step 114, and then the data length of the next frame to be transmitted is decreased at step 115. Finally, in step 116, the counter of the reduced-length frame is loaded before proceeding to step 117 and the transmitting and/or receiving means of the computer station are switched into the transmitting mode (see above).

Summarizing, steps 109 to 112 increase the length of the frame if transmission is not problematic, and decrease the length of the frame at 113 to 116 if transmission is blocked.

Fig. 8 is a schematic flow chart of the steps of a transmission method performed in a watch. First, when a user with a watch is within the coverage area of a computer station, the computer station prompts the user to set the watch to a transmission mode to transmit information in both directions based on the identification number listed in the computer station.

The first step performed by the watch includes activating a transmission mode of a logging function of the watch at step 130. If the transmission mode is active, the channel is immediately searched. A pause of 2.5 seconds can then be applied when nothing is found. After entering the transmission mode, the watch should search for the channel selected by the computer station, step 131, as will be explained below with reference to fig. 9. If the channel search at step 131 fails after a number of attempts, such as after 30 seconds, a message is displayed at step 134 indicating that there is no communication with the computer station. The watch exits the transmission mode at step 135.

Once the transmission channel is found, the watch may communicate with the computer station at step 132, as will be described below with reference to fig. 10. During communication with the computer station, it is possible to lose the connection, for example if the watch temporarily leaves the coverage area of the computer station. If so, it is necessary to re-search the transmission channel in step 131. If the identification number selected by the computer station on the transmission channel (selected carrier) does not relate to the interrogated watch in step 132, it is also necessary to re-search for the transmission channel. Communication in the same coverage area may be between another computer station and another watch. Therefore, the watch should be assigned to another transmission channel in step 131.

At the end of the information transmission between the computer station and the watch, both units send an end frame. A message is then displayed on the watch at step 133 indicating that the call was properly executed, after which the watch exits the transmission mode at step 135.

Fig. 9 shows the steps performed in the watch to search for a transmission channel in step 131. To communicate with the computer, the watch should find the channel or carrier that the computer station has selected. In step 140, the watch transmitting and/or receiving means are activated. The number of channels is set to 5 in step 141 and the channel designated by one data management unit is selected from the 5 available channels in step 142. As a function of the pointing of a channel, the watch attempts to find out the synchronization frame sent by the computer station. If the watch is done counting the number of bytes of the synchronization field received from the computer station at step 143, the transmission channel has been found. On the other hand, if the watch does not complete the sync byte count, another of the 5 transport channels must be pointed to in step 144 and the number of channels is decremented by 1.

In step 145, the number of channels is checked. If the number of channels is not equal to 0, the next step goes to step 142 to select another transport channel. On the other hand, if the number of channels is equal to 0, a correct channel is not found among all the transport channels selected. If a transmission channel is not found, the transmitting and/or receiving means of the watch are turned off in step 146.

In step 147, a check is completed within a maximum time that the watch is in transmission mode but no communication occurs. For example, the maximum time may be set to 30 seconds. If the time expires, no transport channel is found. If, on the other hand, the time has not expired, the watch enters an idle mode, for example idle for 2.5 seconds, in step 148, before reactivating said transmitting and/or receiving means in step 140.

Once the watch is locked to a transmission channel, communication is entered at step 132. Fig. 10 shows the steps of communication between the watch and the computer station. Initially, in step 150, the watch waits for a long string of sync bytes from the computer station or the sync field of the first frame sent from the computer station. Thereafter, in step 151, a counter in the data management unit of the watch counts the number of bytes in the synchronization field of the frame received from the computer station. As a function of the result of counting the sync bytes, a sync indication is sent from the watch to the computer in the header of the next frame, in order for the computer station to correct the size of the next sync field to be sent.

In step 152, upon ending the counting of the bytes of the received synchronization field, the watch receives the header of the frame sent by the computer station in step 153. The header includes an indication to modify the size of the next frame synchronization field transmitted from the watch. If the indication is 0, the next sync field sent by the watch should contain more bytes, and if the indication is 1, the next sync field should contain less bytes.

This allows to dynamically change the length of the synchronization field, which is an advantage of the method according to the invention.

In step 154, an identification number or a universal number received by the watch is checked. If the identification number in the frame sent by the computer station corresponds to the identification number of the interrogated watch, the synchronization calculator is updated in step 155. On the other hand, if the identification number does not correspond to a general number nor to the identification number of the wristwatch being interrogated, the wristwatch should not respond. If so, a subsequent transmission channel is designated in step 144 (see fig. 9).

In step 155, the synchronization calculator updates as a function of the synchronization indications in the frames received from the computer station. The status of this indication sets the number of sync bytes of the next frame sent from the watch. If this indication is 1, the number of sync bytes is increased, and if 0, the number of sync bytes is decreased.

In step 156, the watch receives information of the payload of the packet of the frame and the CRC code. If the watch finds in step 157 that the CRC code indicates a transmission error, the synchronization indication is set to 1 in the packet header of the next frame to be transmitted by the watch in step 161. Thereafter, the erroneously received message is transmitted in step 162. The algorithm goes back to step 150 (waiting for synchronization) through an unsynchronization step 163 involving the watch.

If no transmission error is found in step 157, a device synchronization indication is made in step 158, after which a transmit operation is performed in step 159. At the end of the full transmission of the information, an end signal of one information frame is sent per unit, and the received frame is checked in step 160. If the frame has been received, a similar frame is transmitted to the computer station before the transmitting and/or receiving means of the watch are switched off. Otherwise, the algorithm returns to step 150 (awaiting synchronization of the next frame from the computer station) by showing the asynchrony at step 163.

All information transfer from the watch to the computer station in steps 159 and 162 is described with reference to fig. 11. Initially, in step 170, the transmitting and/or receiving means of the watch should switch from the reception mode Rx to the transmission mode Tx. In step 171, a synchronization field of a frame is first transmitted to the computer station. The number of bytes in the synchronization field depends on the counter update value in step 155 (fig. 10), which is a function of the synchronization indication previously sent by the computer station. After the synchronization field, an information packet is sent in step 172, wherein the header contains a synchronization indication to modify the next synchronization field sent by the computer. The header also includes a code for the type of information being transmitted, as previously described with reference to table I and table II. In step 173, padding bytes are sent to switch the transmitting and/or receiving device. Finally, in step 174, the transmitting and/or receiving apparatus switches from the transmission mode Tx to the reception mode Rx to receive the next frame.

The information transfer method only describes ensuring a complete transfer of information in a minimum time, such as data stored, or to be stored, in a non-volatile memory of a watch. To reduce the time of information transmission and the preparation time of the transmitting and/or receiving means of the watch, so as to minimize the battery energy consumed by the watch during the above-mentioned operation of information transmission. The battery discharge is therefore somewhat slower than in the case of the conventional transmission method, as described in the european patent application with application number EP0957589 in the name of the applicant, which is hereby incorporated by reference.

Note that the power consumption of a watch is several thousand times greater when its transmitting and/or receiving means are active than when it is switched off, and that its power consumption is twice that in the transmitting mode as in the receiving mode.

On the basis of the description given, a person skilled in the art may envisage many methods of wireless information transmission without departing from the scope defined by the claims. Although the communication according to the method of the invention can be envisaged between two watches or two computer stations, the transmission is preferably between one watch and one computer. And the signal transmitted by each unit is preferably a short radio frequency signal, but other types of signals, such as optical or acoustic signals, can be used in the method according to the invention.

Claims (9)

1. A method for wireless transmission of information between at least two units consisting of two computer stations or two personal portable devices or a personal portable device (1) and a computer station (20), said portable device and computer station each having signal transmission and/or reception means (2, 13; 24, 26) for the bidirectional transmission of frames of information (40) modulated on a carrier selected from a large number of available transmission carriers, said transmission and/or reception means (2, 13; 24, 26) being alternately switched to a signal transmission mode and a signal reception mode when they are activated, the portable device (1) comprising a data management unit (12) connected to the transmission and/or reception means (2, 13; 24, 26) for managing the received or transmitted information (40), a memory (11) for storing data, the memory being connected to a data management unit (12), said method comprising the steps of:

-sending an information frame (40) from one unit to another, said information frame (40) being modulated on a selected carrier and comprising a synchronization field (41) consisting of a specific number of bytes of the same value and an information packet (42);

-counting the number of bytes of the synchronization field of the received frame, and

-comparing the counted number of bytes with a specific threshold value to send an indication (49) to correct the number of bytes in the synchronization field of the next frame to be received.

2. The method as set forth in claim 1, characterized by the steps of:

-transmitting from the first unit (20) to the second unit (1) when switching to the transmission mode a first information frame (40) modulated on the selected carrier and comprising a synchronization field (41) comprising a first number of bytes consecutive to a same sample, and an information packet (42);

-counting in the second unit (1) the sync bytes received in the first frame (40) when switching to the receiving mode;

-comparing in the second unit (1) the count of sync bytes in the counted first frame (40) with a specific threshold;

-transmitting from the second unit (1) to the first unit (20) when switching to the transmission mode a second information frame (40) modulated on the selected carrier and comprising a synchronization field (41) comprising a second number of consecutive bytes of the same sample, and an information packet (42) comprising a header (44) containing a synchronization correction indication (49) depending on the comparison of the count value of the number of synchronization bytes in the first frame with a specific threshold value, and

-when switching to the receiving mode, modifying in the first unit (20) the first number of sync bytes by adding or subtracting at least one sync byte in dependence on the modification indication (49) received in the second frame, so as to transmit a third information frame (40) comprising a sync field (41), said sync field (41) comprising a third number of bytes being consecutive and of the same sample, and said third number of bytes being different from the first number of bytes.

3. The method of claim 2, wherein: the information packet (42) in the first frame sent by the first unit (20) includes in the header of the packet of the first frame (40) a further sync correction indication which is based on the result of a comparison of the counted sync byte count in the previously received frame sent by the second unit with a further specific threshold value in order to correct the second number of sync bytes by adding or subtracting at least one sync byte to or from the correction indication sent in the first frame.

4. The method of claim 1, wherein said first unit is a computer station (20) and said second unit is a human watch, characterized in that during a first interrogation between the computer station and the personal watch within the coverage of said computer station, the computer station (20) transmits a basic synchronization signal on a selected carrier, said synchronization signal preceding said first information frame, said synchronization signal occupying a specific time period longer than the synchronization field of each information frame, wherein said personal watch (1) switches to a transmission mode to search for a carrier selected by said computer station from a large number of available carriers after a specific time from the start of the first transmission of the basic synchronization signal from the computer station, and wherein when the watch is able to count a large number of identical bytes of said basic synchronization signal, locking to said selected carrier.

5. A method according to claim 4, characterized in that the header (44) in the information packet (42) in the first frame (40) transmitted by the computer station (20) comprises the identification number of the watch (1) to be interrogated, and that the personal watch transmits a second information frame to the computer station only after it recognises the watch identification number after locking to the selected carrier.

6. The method according to claim 4, characterized in that said computer station (20) repeatedly transmits the basic synchronization signal and the first information frame (40) until the searched personal watch (1) responds to the computer station.

7. A method according to claim 1, characterized in that the header (44) of each information packet (42) comprises a code (48) to indicate the type of information to be transmitted to a portable device such as a watch or to a computer station, the code transmitted in each packet relating to reading data from a non-volatile memory (11) of the watch, writing data to said memory, requesting the identification number of the watch, a message relating to the reception or non-reception of the transmitted information, information about the size of the transmitted data, information about the end of the information transmission.

8. A method according to claim 1, when one of the two units is a computer station, characterized in that the computer station (20) adjusts the size of the information in each packet as a function of the number of transmission errors counted by the computer station error counter being larger than an allowed number of errors.

9. A method according to claim 4, characterized in that the computer station (20) transmits a universal number in the header (44) of the information packet (42) of the first information frame to enable any portable device, such as an unidentified wristwatch (1), within the coverage area of the computer station to respond by transmitting the identification number of said wristwatch, and the computer station stores the identification number of said personal wristwatch that has responded.