JP4778661B2 - Communication system, primary station, secondary station and method - Google Patents

Description

[0001]
[Technical field]
The present invention relates to communication systems, and more particularly to primary and secondary stations for use in such systems and methods for operating such systems. Although the description is made with particular reference to the Bluetooth system, it can be widely applied to other communication systems.
[0002]
[Background technology]
In recent years, much attention has been focused on allowing the devices to interact via wireless communication links, thereby eliminating the need for extension cables. An example of a communication system that can use such a wireless link is a Bluetooth network, which operates according to specifications defined by the Bluetooth Special Interest Group. The intention of such a network is to provide a low-cost short-range wireless link between mobile PCs, mobile phones and other devices whether or not they are portable.
[0003]
Communication in the Bluetooth network is performed in the unrestricted ISM band around 2.45 GHz. The stations form an ad-hoc network known as a piconet, each consisting of a master station and up to seven slave stations. All stations are the same and can operate as a master or slave on demand. A station can enter more than one piconet, thereby linking the piconet and allowing communication over an extended range.
[0004]
One application that has been proposed to use Bluetooth is the connection of a controller device to a host system. A controller device, also known as a human / machine interface device (HID), is an input device such as a keyboard, mouse, game controller, graphics pad, and the like. Such HIDs generally do not require a link with high data throughput, but do require a responsive link.
[0005]
The Bluetooth system can further support HID throughput requirements. However, it is difficult to achieve the required degree of response. An actual Bluetooth link may provide an appropriate response service, but requires both setting up the link and its maintenance even during periods of inactivity.
[0006]
Two types of communication links supported by the Bluetooth network are an asynchronous connectionless (ACL) link and a synchronous connection oriented link. ACL links allow slaves to enter 'park' mode and terminate active communications, and multiple other HIDs maintain links with the master station without breaking Bluetooth rules The rule is that up to seven slaves can be active at a time. Before submitting a request to leave park mode and become active, the slave needs to be polled. The SCO link requires continuous operation by the slave, but only a limited number of SCO channels are available.
[0007]
Setting up the link requires an HID to enter as a slave, and the piconet includes a host system (generally operating as a piconet master or base station). Entering the piconet requires two types of procedures: 'inquiry' and 'page'. The query allows the slave to discover the base station and issue a request to join the piconet. The page allows the base station to accept slaves that have chosen to join the net. An analysis of these procedures reveals that the time it takes to enter the piconet and the time it takes to stay in place to transfer user input to the master can be tens of seconds.
[0008]
This procedure can be executed only once when the host system is booted. However, HIDs typically operate on batteries and are therefore unacceptable to force them to remain powered on permanently. In particular, for HIDs that automatically sign a piconet when the host system is booted, power must be consumed by regular booting to search for Bluetooth query bursts, or manually by the user Must be started.
[0009]
Thus, HIDs tend to be inactive until explicitly switched on or activated by some form of input by the user. Therefore, the Bluetooth master of the host system needs to operate the query cycle periodically, which has two contents. The first is that the initial access time can be tens of seconds because the phase of the query is periodic rather than continuous. This means that it may take 30 seconds or more after the user moves the mouse to the cursor moving on the screen. Second, an inquiry cycle being performed means that the ACL link in that cycle is interrupted for up to 10.24 seconds. Although an SCO link can be used, an HID using such a link cannot suspend transmission in an inactive period.
[0010]
[Disclosure of the Invention]
Accordingly, the present invention aims to provide a positive link between the HID and the host system and allow the HID to sleep during periods of inactivity.
[0011]
According to a first aspect of the present invention, there is provided a communication system comprising a primary station and at least one secondary station, wherein the primary station is in the form of a plurality of predetermined data fields arranged according to a first communication protocol. Means for broadcasting each of a series of inquiry messages and means for adding an additional data field for polling at least one secondary station to the incoming message prior to transmission. The secondary station determines when the additional data field is appended to the multiple data fields, determines whether it is polled from the additional data field, and transmits it to the primary station. There is provided a communication system having means for responding to polling if it has.
[0012]
According to a second aspect of the present invention, a primary station used in a communication system having at least one secondary station, in the form of a plurality of predetermined data fields arranged according to a first communication protocol. A primary station is provided in which means are provided to broadcast an additional data field to each incoming message prior to transmission to broadcast each query message and poll at least one secondary station. The
[0013]
According to a third aspect of the present invention, there is provided a secondary station used in a communication system having a primary station, and means for receiving an inquiry message broadcast by the primary station is provided. Has a format of a plurality of predetermined data fields arranged according to the first communication protocol, and an additional data field for polling at least the secondary station is added thereto, and the additional data field includes a plurality of data fields. A secondary where a means is provided to determine when it was added to the field, determine if it was polled from the additional data field, and if it has data to send to the primary station A station is provided.
[0014]
According to a fourth aspect of the present invention, there is provided a method of operating a communication system comprising a primary station and at least one secondary station, wherein a plurality of predetermined data fields in which the primary stations are arranged according to a first communication protocol. Broadcasts each of a series of inquiry messages, and adds an additional data field to the input message for polling at least one secondary station before transmission, and the polled secondary station adds Determine when a data field was appended to multiple data fields, determine if it was polled from the appended data field, and respond to polling if it has data to send to the primary station However, a method is provided.
[0015]
Embodiments of the present invention will be described below with reference to the accompanying drawings.
[0016]
In the figures, like reference numerals are used for like elements.
[0017]
[Embodiment of the Invention]
In the following description, a system that uses the Bluetooth protocol for message communication between stations will be considered in particular. As will be appreciated, the inventive concept of polling the HID via the broadcast channel used as part of the inquiry procedure is not limited to Bluetooth devices, but particularly to other communication systems in frequency hopping systems. Is available.
[0018]
The basic configuration of the Bluetooth network is shown in FIG. This configuration generally begins with two connected host devices, which are, for example, portable PCs and cellular phones and grow to include additional connection devices. A broad category of additional host devices includes, for example, wireless handsets, portable organizers, and home entertainment devices. The network includes a plurality of stations 100 and 101 each included in such a host device, and is formed into two piconets 102a and 102b. In general, the network elements of all stations 100, 101 (ie, the Bluetooth chip for the Bluetooth network) are configured identically. However, it is only necessary that all the stations 100, 101 forming the network can operate according to compatible protocols.
[0019]
The first piconet 102a is a point-to-multipoint network, and uses a bidirectional communication channel between each of the master 100 and the slave 101 to provide four stations 100, a master 100 (A), and three slaves. 101 (A1, A2, A3). The second piconet 102b is a one-to-one network and includes a master 100 (B) and a slave 101 (B1). Communication between the piconets 102a and 102b is performed when the master A of the piconet 102a operates as a slave of the second piconet 102b and vice versa. For the link between the piconets 102a, 102, it is not required to be between masters: for that link it is equivalent to, for example, the link between stations A3 and B1 or between A and B1. Is possible.
[0020]
An example of a station 100 used in a Bluetooth system is depicted in detail in FIG. 2 and consists of two main parts. The first part is an analog device and has a radio unit (RF) 202 having an antenna 204 for transmitting and receiving radio signals in the communication channel 104. The second part is a digital controller 206, which further includes a link baseband controller (LC) 208, a microprocessor (μP) 210, and an interface device (INT) 212. The link controller 208 has means for performing baseband processing and basic protocol execution close to the physical layer, and performs, for example, error correction coding, automatic repeat request (ARQ), and audio coding. . The macro processor 210 manages the base station 100 and controls data transfer between the interface device 212 and the link controller 208. The interface device 212 has hardware and software for performing an interface function of the base station 100 to a host device such as a portable PC or a cellular phone. The interface is via link 214 and includes interfaces for USB (Universal Serial Bus), external memory and other applications suitable.
[0021]
The Bluetooth inquiry procedure allows a slave 101 to discover a base station and issue a request to enter its piconet. This is proposed to overcome problems due to the frequency hopping nature of Bluetooth and other systems. It is understood by this application that a broadcast channel can be added to the inquiry message issued by the master 100 (piggy-back). It is possible to poll the HID at regular intervals using a broadcast channel. Nevertheless, in the air interface, the mechanism is completely compatible with the conventional Bluetooth system.
[0022]
To illustrate how this is accomplished, consider how the query procedure works with reference to FIGS. When a Bluetooth device wishes to discover another Bluetooth device, it enters a mode called a query substate. In this mode, an inquiry message including a general inquiry access code (GIAC) or a plurality of selectively dedicated inquiry access codes (DIAC) is issued. This message is repeated in several stages; first, it is repeated in a sequence A of 16 frequencies out of a total of 32 forming the query hopping sequence. The message is transmitted twice on two frequencies in an even time slot, followed by an odd time slot that is used to listen for responses on two corresponding inquiry response hopping frequencies. The 16 frequencies and their response counterparts are covered in 16 time slots, ie 10 ms. The chart in FIG. 3 shows a single sequence transmission for 16 frequencies near the center of f {k}, where f {k} represents the query hopping sequence.
[0023]
The next step is to repeat the sequence multiple times. At least as currently specified, this means 256 iterations of the entire sequence. Eventually, sequence A is replaced by sequence B with the remaining 16 frequencies and repeated cycles. As shown in FIG. 4, the specification of the standard ensures that this switching needs to occur at least three times and collects all responses in an error-free environment. This means that an inquiry broadcast takes at least 10.24 seconds.
[0024]
A portable device that wishes to be discovered by the Bluetooth master 100 enters an inquiry scan substate. Then, the message including the target GIAC or DGIAC is monitored. This is also done cyclically. During the interrogation scan period, a single hop frequency is heard, which is long enough to cover the 16 interrogation frequencies used by the interrogation. In monitoring an inquiry that includes an appropriate IAC, the portable device enters a state called an inquiry response substate and issues multiple inquiry response messages to the master 100. The master 100 then calls the mobile device and enters the piconet.
[0025]
As mentioned above and as shown in FIG. 5, the proposal of the present application is that the inquiry messages issued from the base stations have an external field 504 attached to them and can carry HID polling messages. That is. This extended field 504 carries a header, which indicates HID polling and distinguishes it from other applications of extended field information, such as context-aware services and broadcast audio (UK) Patent applications 0015454.2 (Applicant reference number PHGB000084) and 0015453.4 (Applicant reference number PHGB000085, respectively). It can also include the address of the HID being polled, and can carry a small amount of information about the HID, which can be used to supplement information about the user or feedback (such as characters on an LCD screen). (E.g. motion feedback in a game controller) can be provided. By adding this field to the end of the inquiry message, non-HID receivers can ignore it without modification. Furthermore, by using a specific DIAC to specify HID polling, the HID device can be informed of the presence of an upcoming poll.
[0026]
The presence of the external data field 504 means that the guard space previously allowed at the end of the Bluetooth query packet is reduced. However, this space is provided to give the frequency synthesizer time to change to a new hop frequency and is not generally used because the current frequency synthesizer has an extra guard guard. This is because it is possible to switch at a speed that does not require expansion into space. The standard inquiry packet is a 68-bit ID packet (ID PKT) 502. Since this is transmitted in half-slots and starts at slot boundary (SB) 506 or half-slot boundary (HSB) 508, the allocated guard space is (625 / 2−68) = 244.5 μs (one slot period is 625 μs) And a signal rate of 1 Mbit / sec.). Modern synthesizers are capable of switching in a short period of time of 100 μs or lower numbers considered by those skilled in the art. Therefore, a suitable size for the external data field 504 can be 100 bits.
[0027]
According to this embodiment, 4 out of 100 bits are lost as trailer bits for the ID packet 502. This is read by the correlator. For the remaining 96 bits, the preferred allocation according to the present application is that 64 bits are used as data and 32 bits are used as 2/3 FEC (forward error correction) checksum. Each query burst contains 8 bytes of broadcast data and allows space for several channels of analog input that are key encoded or digitized.
[0028]
Since the HID is specifically addressed to achieve the desired responsiveness, the HID can respond every other half-slot as needed, as well as including information corresponding to user input. Use a packet with a proper format. As described above, the inquiry procedure includes two sets of 16 frequency transmissions in the inquiry transmission sequence. The 16 frequencies used in a sequence can be considered as 16 polling channels, so that 16 devices can be polled every 10 ms as needed. Other systems are possible, for example, up to 32 devices can be polled every 20 ms, or up to 8 devices can be polled every 5 ms. Polling channel placement is also flexible, allowing faster polling to devices that require faster response times and vice versa.
[0029]
Each device only needs to monitor a single frequency in its sequence, but needs to be able to track sequence switching and frequency changes due to clock phase changes. The initial setup procedure synchronizes the HID Bluetooth slave 101 with the Bluetooth master 100 in addition to determining the attributes of the HID and the format used for uplink and downlink transmission. At this point, a device address and channel number corresponding to one of the 16 channels in the sequence is assigned to the HID.
[0030]
For fast polling, the Bluetooth master 100 needs to operate continuously. This conflicts with conventional mechanisms for setting up bi-directional links. However, as disclosed in UK patent application 0015452.6 (applicant reference number PHGB000086), this problem is avoided by utilizing two radios operating in tandem, and high speed to the piconet. Allows access and allows unlimited bidirectional throughput capacity.
[0031]
By polling every 10 ms using 8 bytes per poll, a capacity of 800 bytes per second is provided for 16 devices. In the modification of the basic method described above, it is possible to reduce the capacity to allow the operation of the existing inquiry procedure, or to increase the number of HIDs so that the host system 100 can support 16 or more. It is also possible to do so.
[0032]
In order to minimize power consumption, if no information is provided to them, the HID is not forced to respond to all polls. It is possible to provide a watchdog timer in the HID and transmit it at least once in a given period while acting in a nominal manner. The period can be predetermined, for example, can be determined by the host system, or can be determined by negotiation between the host and each HID. If the HID fails to transmit within a defined period, it is deleted from the master's own list of active devices.
[0033]
The method for polling HID according to the present invention is summarized in FIG. When the HID sends data to the host system, the method begins at step 602. The HID receives data from the external field 504 at step 604 and checks whether it was polled by the host system at step 606. If not, the HID returns to step 604 to receive the next external data field 504. If the HID has been polled, in step 608, the data is transmitted after a half slot is available.
[0034]
Since a query mode is required to allow access to the host system's piconet, it must be provided in a conventional manner at least sometime. There are several methods available.
[0035]
The first approach involves one wireless operation in two modes, configuration and polling. In the setting mode, the inquiry procedure operates as usual, and the HID establishes contact with the host master 100 in a conventional manner. When all the HIDs are set by themselves, the master performs wireless switching to the polling mode, and the inquiry procedure in this case operates only in the polling mode. This approach is preferred for game consoles, where the fastest responsiveness is achieved when the polling mode is performed, while the opportunity for other controllers to join the piconet is clearly defined, such as during a game. Because it occurs in time.
[0036]
The second method is more appropriate when the host system is a general-purpose device such as a PC, and in this case, a new device that enters at an arbitrary time is provided. In this case, the master radio can operate in a mode-independent format, perform high-speed polling at a certain time, and perform a normal inquiry operation at another time. The 10 ms period of switching can be assigned to achieve a ratio of, for example, 50:50 for each operation, and the radio can be modified as needed. Such a system has a very fast HID response and a general interrogation operation, but it can also be slower to perform normal operations. Utilizing a specific DIAC in the polling message ensures that the slave 101 going to the normal inquiry response procedure does not send inquiry response packets in the space reserved for fast polling responses.
[0037]
Performing regular queries in parallel with fast polling sometimes results in a slight pause in the query and also provides fast polling to allow new HIDs to access the host. This is probably not critical to the user. This is because the user will no longer use the old HID and will not notice a primary loss in responsiveness.
[0038]
The third approach is required when a traditional Bluetooth data (or other) link is required and supports both the fast response for the polling mechanism and the traditional Bluetooth data carrying capacity. . This requires the use of two radios, and the technique disclosed in UK patent application 0015452.6 (applicant reference number PHGB000086) can also be used here. Alternatively, one radio can be used as a conventional Bluetooth radio by using something permanently dedicated to fast polling.
[0039]
Other modifications will be possible to those skilled in the art from the description herein. Such variations include other features known in the art of design, manufacture and use of fixed or portable communication systems and components, and include other features in place of or in addition to those described above. The claims are formed in the form of combinations of features herein, but the scope of the present disclosure includes any novel features, express or implied, or generalized thereof. Any combination of the disclosed features is included, whether or not it relates to the same invention as the claimed invention, all or part of the same technical problem as the present invention has made It does not depend on whether or not to reduce. In the present patent application, new claims may be formed by such features and / or combinations of features and others that may be derived.
[0040]
In the present specification and claims, the word “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. Further, “comprising” in the original text does not exclude other elements or steps than those listed.
[Brief description of the drawings]
FIG. 1 shows an ad hoc wireless network consisting of two linked piconets.
FIG. 2 is a schematic block diagram of a general Bluetooth station.
FIG. 3 is a chart for explaining transmission of an inquiry access code sequence centered on a given frequency.
FIG. 4 shows switching of inquiry message sequences during an inquiry broadcast period.
FIG. 5 shows the insertion of broadcast data packets for an existing transmission slot.
FIG. 6 is a flowchart illustrating a method for polling HID according to the present invention.

Claims (27)

A communication system that having a primary station and at least one secondary station, the primary station, a series of interrogatory messages for the secondary station to discover the primary station comprising means for broadcasting, the respective inquiry message is formed by a plurality of predetermined data fields arranged according to communication protocol, and means, the additional data field for polling specific secondary station to the series of interrogatory messages and means for adding prior to transmission, the specific secondary station, said additional data field has a means you another determine whether it is added to the series of inquiry messages, communication system. The specific secondary station responds to the polling when means for determining whether or not the primary station is polled and the specific secondary station has data to be transmitted to the primary station The communication system according to claim 1, comprising: means. 4. The communication system according to claim 3, wherein the specific secondary station is a human / machine interface device (HID) and the additional data field includes a HID polling message. The communication system according to claim 3, further comprising means for responding to the additional data field when the HID is in an inactive connection state. The additional data field for polling includes a unique ID for the particular secondary station, and when the particular secondary station detects the unique ID, means for responding in a designated time slot The communication system according to claim 1. The means for broadcasting broadcasts the series of inquiry messages by a plurality of frequencies, and the specific secondary station adds the additional data field to any one of the plurality of frequencies. 6. The communication system according to claim 5, wherein said specific secondary station has means for responding to polling using any of said plurality of frequencies. The communication system according to claim 6, wherein the specific secondary station is a wireless device powered by a battery. The communication system according to claim 1, wherein the communication protocol is based on Bluetooth. The communication system according to claim 1, wherein the number of active secondary stations is limited by the communication protocol. A primary station for use in a communication system having at least one secondary station,
Secondary station and means for broadcasting a series of inquiry messages to discover the primary station, each of the query message is formed by a plurality of predetermined data fields arranged according to communication protocol Means , and
Means for adding an additional data field for polling a particular secondary station to the series of inquiry messages prior to transmission ;
Having a primary station. It said additional to means adds the additional data field at the end portion of the query message each primary station of claim 10, wherein. At least one further comprises means that include primary station of claim 10, wherein one of the indication of the presence of additional data fields wherein the predetermined data field. The primary station of claim 10 , wherein the additional data field includes at least 64-bit data. 11. A primary station according to claim 10, wherein a first wireless means is provided for broadcasting the inquiry message substantially continuously. Before SL communications protocol is due to Bluetooth, the primary station of claim 10, wherein. Limiting the number of active secondary stations by the communication protocol, according to claim 1 primary station as claimed. A secondary station for use in a communication system having a primary station comprises means for receiving a broadcast by inquiry message by the primary station, the query message includes a plurality of which are arranged according to communication protocol A data field formed by a predetermined data field and for discovering the primary station, an additional data field for polling the secondary station is added to the inquiry message ; It said additional data field has a means for determining whether it is pressurized with the plurality of data fields, the secondary station.   The additional data field is for polling the secondary station. The secondary data field determines whether or not the secondary station is polled, and the secondary station transmits to the primary station. 18. A secondary station according to claim 17, comprising means for responding to polling if it has data to do. Data after a lapse of a period of Jo Tokoro without sending, the secondary station is Ru Tei is provided means for responding to polls whether they have data to be transmitted, the secondary station according to claim 17 . 18. A secondary station according to claim 17, implemented as a human / machine interface device (HID). 21. The secondary station according to claim 20, wherein the HID is a wireless device powered by a battery. The primary station broadcasts the series of inquiry messages by a plurality of frequencies, and the HID determines that the additional data field is added to any of the plurality of frequencies, 21. The secondary station of claim 20, wherein the HID comprises means for responding to polling using any of the plurality of frequencies. 23. The secondary station of claim 22, wherein said means for responding responds using a time slot designated for any of said plurality of frequencies. In which pre-Symbol communications protocol according to the Bluetooth, the secondary station according to claim 17. The secondary station of claim 17, wherein the number of active secondary stations is limited by the communication protocol. A method in a communication system having a primary station and at least one secondary station, the primary station broadcasts a series of inquiry messages, each of the query message includes a plurality of predetermined ordered according to a communication protocol Formed by a data field and for the secondary station to discover the primary station, the method transmitting an additional data field for polling a specific secondary station to the series of inquiry messages Prepend the method. 27. The method of claim 26 , wherein the additional data field is appended to each of the series of inquiry messages .

Images