KR100719791B1 - Communication systems - Google Patents

Abstract

The communication system includes one primary station 100 and at least one secondary station 101. The primary station 100 is arranged to broadcast a series of inquiry messages, each in the form of a plurality of predetermined data fields arranged according to a first communication protocol such as Bluetooth. In addition, the primary station 100 adds an additional data field to some or all of the inquiry messages for polling one or more secondary stations that may respond to polling if it has data for transmission. This system provides fast response time for secondary stations 101 without the need for a permanently active communication link.

Communication protocol, inquiry message, polling, communication link, fast response time

Description

Communication system             

The present invention relates to a communication system, and also to a primary station and a secondary station used in such a system, and a method of operating such a system. Although the present invention is described with particular reference to a Bluetooth system, it is applicable to other communication systems in any range.

Recently, there has been increasing interest in allowing devices to communicate over wireless communication links so that extensive cable cabling is not required. One example of a communication system that can be used for such wireless links is a Bluetooth network that operates in accordance with the specifications defined by the Bluetooth Special Interest Group. Such a network is intended to provide low cost, short range wireless links between mobile PCs, mobile phones and other devices, whether portable or not.

Communication in the Bluetooth network is in the unlicensed ISM band of approximately 2.45 GHz. Communication stations form particular networks known as piconets, each containing one master communication station and up to seven slave communication stations. All communication stations are identical and can operate as master or slave as needed. One communication station may participate in one or more piconets, thereby linking the piconets and enabling communication over a wide range.

One application proposed as the use of Bluetooth is to connect controller devices to host systems. Controller devices, also known as human / machine interface devices (HIDs), are input devices such as keyboards, mice, game controllers, graphics pads, and the like. Such HIDs generally do not require links with high data throughput, but require very fast links.

The Bluetooth system can support throughput requirements of HIDs. However, the required degree of response can be difficult to achieve. An active Bluetooth link may provide the desired response service, but also requires maintenance of the link during setup and inactivity.

Two types of communication links supported in a Bluetooth network are Asynchronous ConnectionLess (ACL) links and Synchronous Connection Oriented (SCO) links. ACL links allow slaves to enter a 'park' mode and suspend active communications, thus a number of different HIDs without contradicting the Bluetooth rule that only seven slaves can be active once. To maintain links with the master station. The slave must be polled before requesting to release the park mode and go into active mode. SCO links require continuous operation by the slave, but only a limited number of available SCO channels exist.

The setup of the link requires that the HID join as a slave to the piconet that contains the host system (typically acting as a piconet master, i.e., a base station). Coupling with the piconet requires two sets of procedures, 'inquiry' and 'page'. The inquiry enables the slave to find the base station and issue a join request with the piconet. The page enables the base station to allow selected slaves to join the piconet. Analysis of these procedures indicates that the time it takes to bind a piconet to a location capable of sending user input to the master may be tens of seconds.

This procedure can be executed when the host system is turned on. However, HIDs are typically battery operated and, therefore, cannot be permanently switched on. In particular, in order for the HID to automatically initiate the piconet when the host system is turned on, it must be regularly activated for discovery of Bluetooth inquiry bursts, thereby consuming power and being manually activated by the user.

Therefore, the HID remains inactive until it is activated by being surely switched on or by a user attempting some form of input. Therefore, the Bluetooth master of the host system must periodically drive the inquiry cycles, which has two implications. The first implication is that the initial access time can be tens of seconds because the lookup phase is not continuous but periodic. This means that it may take more than 30 seconds from the point where the user moves the mouse towards the cursor moving on the screen. Next, the fact that the lookup cycle occurs on all means by which ACL links are suspended for up to 10.24 seconds at a time during the lookup cycle. Although SCO links may be used, an HID using such a link may not stop transmitting during inactive periods.

It is an object of the present invention to address the problem of providing a response link between the HID and the host system that causes the HID to become stationary during inactive periods.

According to a first aspect of the invention, there is provided a communication system comprising one primary station and at least one secondary station, wherein the primary station comprises a plurality of predetermined data fields each arranged according to a first communication protocol. Means for broadcasting a series of inquiry messages in form; Means for adding an additional data field to the inquiry message prior to transmission to poll at least one secondary station, wherein the polled secondary station or each polled secondary station has a plurality of additional data fields; It has a means for determining when to add data fields, determining if it has been polled from the additional data field, and responding to a poll when it has data for transmission to the primary station.

According to a second aspect of the invention there is provided a primary station for use in a communication system comprising at least one secondary station, where a series of predetermined data fields are each in the form of a plurality of predetermined data fields arranged according to a first communication protocol. Means are provided for broadcasting the inquiry messages and adding an additional data field to each inquiry message before transmission to poll at least one secondary station.

According to a third aspect of the invention, there is provided a secondary station for use in a communication system comprising a primary station, wherein means are provided for receiving an inquiry message broadcast by said primary station, said message being a first communication. In the form of a plurality of predetermined data fields arranged according to a protocol, an additional data field is added to poll at least one secondary station, determining when an additional data field is added to the plurality of data fields and Means are provided for determining whether to poll from the additional data field and for responding to the poll when it has data for transmission to the primary station.

According to a fourth aspect of the invention there is provided a method of operating a communication system comprising a primary station and at least one secondary station, wherein the primary station comprises a plurality of predetermined stations each arranged according to a first communication protocol. Broadcast a series of inquiry messages in the form of data fields and add additional data fields to the inquiry message before polling at least one secondary station, wherein the polled secondary station or each polled secondary station, Determine when an additional data field has been added to the plurality of data fields, determine if it has been polled from the additional data field, and respond to the poll when it has data for transmission to the primary station.

Embodiments of the present invention will now be described with reference to the accompanying drawings as an example.

1 is a diagram of a specific wireless network including two linked piconets.

2 is a block diagram of a typical Bluetooth communication station.

3 is a chart illustrating transmission of an inquiry access code string centered on a given frequency.

4 illustrates a change between query message columns in a period of query broadcasting.

5 illustrates insertion of a packet of broadcasting data in an existing transport slot.

6 is a flow diagram illustrating a method for polling an HID in accordance with the present invention.

In the drawings, like reference numerals have been used to indicate like configurations.

Modes for Carrying Out the Invention
In the following description, particular consideration is given to a system using Bluetooth protocols for message communication between communication stations. As can be seen, the inventive concept of polling of HIDs over a broadcasting channel used as part of an inquiry procedure is not limited to Bluetooth devices and is applicable to other communication arrangements, in particular frequency hopping systems.

A basic Bluetooth network configuration is illustrated in FIG. Such a configuration generally begins with two connected host devices, such as a portable PC and a cellular phone, and grows to include additional connected devices. A wide variety of additional host devices may be included, such as wireless headsets, personal organizers, and home entertainment devices. The network includes a plurality of communication stations 100, 101, each of which is included in such a host device formed of two piconets 102a, 102b. In general, the networking components of all communication stations 100 and 101 (ie, Bluetooth chips for Bluetooth networks) will be implemented identically. However, all communication stations 100,101 including the network must operate according to compatible protocols.

The first piconet 102a comprises four communication stations 100, one master 100 (A) and three slaves 101 (A1, A2, A3). to-multipoint) network, which has a bidirectional communication channel 104 between the master 100 and each of the slaves 101. The second piconet 102b is a point-to-point network comprising a master 100 (B) and a slave 101 (B1). Communication between the piconets 102a, 102b is enabled by the master A of the first piconet 102a, which acts as a slave in the second piconet 102b, and vice versa. The link between the piconets 102a and 102b need not be between masters. That is, the link may be, for example, between communication station A3 and communication station B1 or between A and B1.

An example of a communication station 100 used in a Bluetooth system is shown in detail in FIG. 2 and also includes two main parts. The first portion is an analog unit that includes a radio (RF) 202 having an antenna 204 for transmitting and receiving wireless signals on the communication channel 104. The second portion is a digital controller unit 206 further comprising a link baseband controller (LC) 208, a microprocessor (μP) 210, and an interface unit (INT) 212.

The link controller 208 includes means for performing baseband processing and execution of basic protocols adjacent to the physical layer, for example, implementing error correction coding, generating an automatic repeat request (ARQ), and also performing audio coding. . The microprocessor 210 manages the communication station 100 to control data transmission between the interface unit 212 and the link controller 208. The interface unit 212 includes hardware and software for interfacing the communication station 100 to a host device such as a portable PC or a cellular phone. Interfacing is performed via link 214, which may include interfaces to Universal Serial Bus (USB), external memory, and other items appropriate for a particular application.

The Bluetooth inquiry procedure enables the slave 101 to issue a request to discover the base station and join it to its piconet. In particular, it has been proposed to overcome the problems caused by the frequency hopping nature of Bluetooth and similar systems. Applicants have found that they can piggy-back the broadcasting channel for inquiry messages generated by the master 100. The broadcasting channel may be used to poll HIDs at regular intervals. However, at the air interface, the mechanism is fully compatible with existing Bluetooth systems.

In order to explain the implementation method, first, how the inquiry procedure itself operates will be considered with reference to FIGS. 3 and 4. When the Bluetooth unit wants to discover other Bluetooth devices, it becomes a so-called inquiry substate. In this mode, the unit generates an inquiry message that includes a general inquiry access code (GIAC) or a plurality of optional dedicated inquiry access codes (IDAC). This message is repeated at various levels. That is, it is first repeated in a frequency column A consisting of 16 frequencies from a total of 32 frequencies constituting the inquiry hopping sequence. The message is sent twice on two frequencies of even timeslots with subsequent odd timeslots used to listen for responses to two corresponding inquiry response hopping frequencies. Therefore, sixteen frequencies and their response frequencies can be covered within sixteen timeslots, that is, 10 ms. The chart of FIG. 3 shows the transmission of a single frequency string on 16 frequencies centered on f {k}, where f {k} represents an inquiry hopping sequence.

The next step is to repeat the plurality of times in the frequency sequence. At the very least, as currently indicated, this means 256 repetitions of the entire frequency sequence. Finally, frequency column A is swapped into frequency column B consisting of the remaining 16 frequencies, and the cycle is repeated. As shown by FIG. 4, it can be seen from the specification that this switch should occur at least three times to ensure the collection of all responses in an error free environment. This means that query broadcasting can take at least 10.24 seconds.

The portable device wishing to be discovered by the Bluetooth master 100 is in the inquiry scan substate. Here, the device listens to a message including the corresponding GIAC or DIAC. The device also operates periodically. The apparatus listens to a single hop frequency for an inquiry scan period long enough to cover the sixteen inquiry frequencies used by the inquiry. Upon listening to an inquiry containing the appropriate IAC, the portable device enters a so-called inquiry response substate and generates a plurality of inquiry response messages to the master 100. Next, the master 100 pages the portable device to couple to the piconet.

As mentioned above and shown in FIG. 5, Applicant proposes that the inquiry message generated by the base station has an extra field 504 attached to it, which can carry the HID poll message. The extension field 504 includes context aware services or broadcasting audio (published with pending UK Patent Application No. 0015454.2 (Applicant Control Number PHGB 000084) and 0015453.4 (Applicant Control Number PHGB 000085), respectively). A header indicating the HID poll may be carried to distinguish it from other applications of the same extended field information. It will also convey the address of the HID being polled, and will pass a small amount of information (e.g., text on the LCD screen) or feedback (e.g., motion feedback of game controllers) to the HID that may be used to provide supplemental information to the user. It may be. By adding the field to the end of the inquiry message, it can be seen that non-HID receivers can ignore it without modification. In addition, by using a specific DIAC to represent the HID poll, HID devices can be alerted for the presence of this poll.

The presence of the redundant data field 504 means that the previously allowed protected space at the end of the Bluetooth inquiry packet is reduced. However, this space is provided to give the frequency synthesizer time to changes to the new hop frequency, and in general, current frequency synthesizers can switch at a rate that does not need to be extended to the extra protective space, and thus will not be used otherwise. . The standard inquiry packet is an ID packet (ID PKT) 502 of 68 bits in length. Since the transmission starts on a one slot boundary (SB) 506 or a half slot boundary (HSB) 508 and into a half slot, the allocated guard space is (625 / 2-68) = 244.5 μ (625 μs). Slot duration, 1 Mbits / s signal rate). Modern synthesizers can be switched by experts in the art in much shorter 100 μs times or in fewer routines. Thus, a suitable size for the extra data field 504 may be 100 bits.

In a typical embodiment, four of the 100 bits are lost as trailer bits for the ID packet 502, which is the result of being read by the compensator. Among the remaining 96 bits, Applicants' preferred allocation is that 64 bits are used as data and 32 bits are used as a 2/3 Forward Error Correction (FEC) checksum. Thus, each inquiry burst contains 8 bytes of broadcasting data, thus freeing up several channels of key coded or digitized analog inputs.

In order to achieve the desired responsiveness, the HID is also clearly addressed, so that the HID will respond in half slots next but by a similarly formatted packet containing information corresponding to the user's input if desired. Can be. As described above, the inquiry procedure involves two sets of transmissions of inquiry frequencies of 16 frequencies in a column. The sixteen frequencies used in one column may be considered as sixteen polling channels, and thus sixteen devices may be polled every 10 ms if desired. For example, other arrangements are available that poll up to 32 devices every 20 ms or up to 8 devices every 5 ms. The arrangement of polling channels is flexible, and faster polling is provided for devices requiring faster response times.

Each device only requires monitoring of a single frequency within one frequency column, but must be able to track frequency column transitions and frequency changes due to clock phase changes. The initial setup procedure not only forms the nature of the HID, and the format used for uplink transmission and downlink transmission, but also synchronizes the HID Bluetooth slave 101 to the Bluetooth master 100. At this time, the channel number and the device address corresponding to one of the 16 channels in the frequency column are assigned to the HID.

For high speed polling, the Bluetooth master 100 needs to operate continuously. The master is interfaced with an existing mechanism to set up two way links. However, the use of two serially operating radios, published in Applicant's co-pending British Patent Application No. 001452.6 (Applicant Control Number PHGB 000086), overcomes this problem and thereby provides a high speed for the piconet. Access and unlimited two way processing capacity may be provided.

By polling every 10ms, 8 bytes per poll, 800 bytes per second capacity is provided for 16 devices. With the change in the basic technology described above, the capacity can be reduced to allow operation of existing inquiry procedures or to increase the number of HIDs that the host system 100 can support for more than 16.

In order to minimize the power consumption of the HIDs, the HIDs are not forced to respond per pole when there is no information to supply. In normal operation, a watchdog timer may be provided to the HID to allow transmission at least once during a given period of time. The time period determined by the host system or by compromise between the host and each HID may be predetermined, for example. Next, HIDs that did not transmit within the determined time period are removed from the master's list of active devices.

The method for polling the HID according to the present invention is summarized in FIG. This method begins in step 602 when the HID has data for transmission to the host system. The HID receives data from the extra field 504 in step 604 and then tests whether it has been polled by the host system in step 606. If the HID has not been polled, the HID returns to step 504 to receive the next extra field 504. If the HID has been polled, the HID sends the data to the next but half slot in step 608.

The inquiry mode is necessary to allow access to the piconet of the host system, so it must be provided in a conventional manner during at least some of the time. There are a range of strategies that may be used.

The first strategy involves the operation of one radio in two modes, setup mode and polling mode. In setup mode, the lookup procedure operates as usual, and the HIDs can make contact with the host master 100 in a conventional manner. Once all HIDs have been formed, the master radio is switched to polling mode, in which the inquiry procedure now operates only in polling mode. This strategy is ideal for game machines as it can achieve the fastest response when operating in polling mode, but the opportunities of other controllers to join the piconet arise between well defined times, for example between games. .

The second strategy is more suitable when the host system is a general purpose device such as a PC, in which case opportunities should be provided for new devices to be combined at any time. In this case, the master's radio can operate in a modelless format, so part of that time is used for fast polling and another time is used for existing inquiry operations. Other 10 ms periods are used for each operation, for example to achieve a 50:50 ratio, which ratio can be modified as desired. Such a system still has a fast response to the HIDs, and the normal lookup operation may be slow, but it will work as usual. The use of a particular DIAC in the polling message should ensure that the slave 101 proceeding through normal inquiry response procedures will not send an inquiry response packet in the space reserved for the fast poll response.

Allowing existing lookups at the same time as fast polling implies that there is a pause in the lookup or fast polling to allow new HID access to the host. This is no problem for the user since they no longer use previous HIDs and are not aware of the temporary loss of responsiveness.

A third strategy is required when existing Bluetooth data (or other data) links are needed to support high speed response for data and polling mechanisms that carry the capacity of existing Bluetooth. Accordingly, the use of two radios is required, and the method disclosed in Applicant's co-pending UK Patent Application No. 0015452.6 (Applicant Control Number PHGB 000086) may be used here. In addition, one radio may act as an existing Bluetooth radio with another radio permanently dedicated to fast polling.

From this specification, other variations will be apparent to those skilled in the art. Such variations may include other features already known in the art of design, manufacture, and use of fixed or portable communication systems and their components, and may be used instead of or in addition to the features already described herein. . In the present application, the claims are made up of specific combinations of features, but the scope of the present application is not related to any new configuration or whether or not it relates to the same invention currently claimed in the claims or to overcome the same technical problem as the present invention. It is to be understood that this includes new combinations of configurations that are explicitly or implicitly disclosed. Applicant informs us that new claims may be constructed in such configurations and / or combinations of configurations during the course of this application or other applications derived from this application.
In this specification and claims, the singular form of the device does not exclude the presence of a plurality of such devices. In addition, the term "comprising" does not exclude the presence of elements or steps other than the listed elements or steps.

delete

Claims (12)

A communication system comprising one primary station and at least one secondary station, The primary station, Means for broadcasting a series of inquiry messages, each in the form of a plurality of predetermined data fields arranged according to a first communication protocol; And Means for adding additional data fields to the inquiry message prior to transmission to poll at least one secondary station, The polled secondary station or each polled secondary station determines when an additional data field has been added to the plurality of data fields, determines whether it is polled from the additional data field, and transmits to the primary station. And means for responding to a poll when it has data to do so. A primary station for use in a communication system comprising at least one secondary station, Broadcast each series of inquiry messages, each in the form of a plurality of predetermined data fields arranged according to the first communication protocol, and send each data message prior to sending an additional data field to poll at least one secondary station. A primary station is provided for adding means. The method of claim 2, Means for adding the additional data field to the end of each inquiry message. The method of claim 2 or 3, Means for including an indication in a data field of one of the predetermined data fields, the indication indicating the presence of the additional data field. The method of claim 2 or 3, And wherein said first communication protocol comprises Bluetooth messaging. The method of claim 2 or 3, And the additional data field comprises at least 64 data bits. The method of claim 2 or 3, A first radio means is provided for substantially continuous broadcasting of inquiry messages with said additional data field, and a second radio means is provided for handling other features of communication links with secondary stations. The first station to say. In a secondary station for use in a communication system comprising a primary station, Means for receiving an inquiry message broadcast by the primary station, the message being in the form of a plurality of predetermined data fields arranged in accordance with a first communication protocol and adding an additional data field to it to poll at least one secondary station. In addition, the receiving means is provided, Means for determining when an additional data field has been added to the plurality of data fields, determining if it has been polled from the additional data field, and responding to a poll when it has data for transmission to the primary station Secondary station. The method of claim 8, And the first communication protocol comprises Bluetooth messaging. The method according to claim 8 or 9, Means for responding to a poll after a predetermined interval has elapsed without transmitting data, whether or not the secondary station has data for transmission. A method of operating a communication system comprising a primary station and at least one secondary station, The primary station broadcasts a series of inquiry messages, each in the form of a plurality of predetermined data fields arranged according to the first communication protocol, and before transmitting the additional data field to poll at least one secondary station. In addition to the inquiry message, The polled secondary station or each polled secondary station determines when an additional data field has been added to the plurality of data fields, determines whether it is polled from the additional data field, and transmits to the primary station. Responding to a poll when it has data to do so. The method of claim 11, Characterized in that not all inquiry messages have an additional data field for polling a secondary station added to these inquiry messages.

Images