DE10048465A1 - Method for operating a short-range radio transceiver, in particular a "Bluetooth" device, on a universal serial bus "USB" - Google Patents

Abstract

The invention relates to a method for operating a short-range radio transmitting/operating receiving device, especially a "Bluetooth" device, on a universal serial bus "USB". According to the inventive method, pseudo data are sent to the USB during normal operation of a terminal in periods in which no useful or control data reach USB through the "Bluetooth" device. During a power-saving mode of the USB, individual function units of the short-range transmitting/receiving device are at least partially deactivated.

Description

The invention relates to a method for operating a Short-range radio transmitter / radio receiver, especially egg nes "Bluetooth" device, on a universal serial bus "USB".

The "Bluetooth standard" is a short-range radio standard, the one with carrier frequencies from the worldwide unlicensed "Industrial", "Scientific", "Medical" 2.4 GHz band (ISM- Band) works and a wireless connection of end devices ten (devices) in a radio cell with a radius of up to 10 Meters, in special cases even up to 100 meters possible, the carrier frequencies to avoid radio interference prevent in a (pseudo) random order Be changed 1600 times per second. For this frequency "Frequency hopping" are up to 79 frequencies (Channels) in the range between 2.402 and 2.480 GHz.

Up to eight Devi that work according to the Bluetooth standard ces can in the - also referred to as "pico cell" - Radio cell merged into a so-called "pico network" be and communicate with each other, the individual Devices - realized by time-division multiplexing - members which can be multiple pico networks, so these pico networks thereby connected to a so-called "scatter network".

Every device in a pico network can initiate this pico network ALISE. A device that has initialized a pico network controls the remaining members of the Pico network and synchronizes their timers, so it will be "master" draws while the remaining members of the Pico- Network are referred to as "slaves".  

Devices that are members of several Pico networks and these Pico networks that are characterized by different hopping channel Differentiate sequences, combine into scatter networks, syn chronicle themselves in each multiplex time slot because current master.

Before you establish a connection in the Pico network Bluetooth devices are in a standby Mode ". Unconnected devices search every 1.28 seconds after possible network news.

In addition to the standby mode without a network connection, there is another A number of other power saving functions possible. In "hold mode" the device remains integrated in the Pico network, but it will no data transmitted. Only an internal timer runs in the Slave further. If necessary, data transmission starts with a delay delay-free. Hold mode can start from the master for the slave be ordered. On the other hand, the slave can request the master switch it to this mode.

In "sniff mode" the device listens in programmable Ab were in the network. Here, too, the timer runs for synchronization sation in the slave.

Devices can also be parked in the network ("Park mode"). The device loses its address in the network and can Network traffic only tracked and synchronized in its internal timer with that of the master.

The "USB standard" is a bus standard for connecting Peripherals via a "USB port" on a PC (host PC) and is designed as a combined star-bus structure, whereby Similar to the Bluetooth standard, several - up to 127 - devices (Devices) in parallel on a "USB" (Universal Serial Bus) can be closed and controlled by a master (USB host Adapter in the PC).  

Individual devices or devices can be connected to the outputs of the host adapter "USB hubs" can be connected. At the latest with more than two Such a hub is necessary as a distributor for USB devices. ne In addition to the power distribution, the hubs also ensure that mer only a USB device sends its data to the host controller. The hubs can be cascaded as required.

To devices with different transmission speeds To be able to connect is the transmission via USB in Ka channels divided.

For "slow" devices there is a "low-speed channel" with up 1.5 Mbit / s and a "medium-speed channel" with 12 Mbit / s be routed through the same interface. A "high-speed Channel "with 500 Mbit / s is also provided.

In contrast to Bluetooth, the USB standard is only one Power saving mode provided. This "suspend mode" must be switched on be forwarded as soon as no data traffic on the USB Interface is present.

The increasing convergence of information and telecommunications cation networks suggests that Bluetooth and USB devices should be connected the, especially since USB and Bluetooth systems ver have a similar hierarchical structure.

The object underlying the invention is a Ver driving to indicate that operating a short-haul Radio transmitting / radio receiving device, in particular a "Blue tooth "device, on a universal serial bus" USB "he made possible.

This object is achieved by the features of patent claim 1 solved.

In the method according to the invention for operating a short-range radio transceiver, in particular  a "Bluetooth" device on a universal serial Bus "USB" during normal operation of the device Periods in which no user or tax data about the Terminal device get to the USB, pseudo data sent to the USB and during a power saving mode of the USB, single function units of the short-range radio transmitter / receiver at least partially switched off.

One of the main advantages of the method according to the invention rens is that in the case of the short-range radio transmitter - / - Radio receiving device temporarily not in use or Control data on the USB (port) if the Power saving mode of the universal serial bus on very is simply prevented. Furthermore there is also a Unintentional termination of the power saving mode due to high current avoided on the part of the radio transceiver, the orientation or adaptation to the power saving mode of the universal serial bus also contains the Advantage that only the conditions for a power saving mode must be monitored and complied with, as for the (USB) Technology only a power saving mode is defined.

Further advantageous embodiments of the invention are shown in specified in the subclaims.

An embodiment of the invention is based on the one shown figure. This shows:

Exemplary course of the current consumption of one at a universal serial bus connected Bluetooth De vices in slave mode

In the figure, the course of an electrical current I _Bth required by a short-range radio transmitter / radio receiver device (Bluetooth device, Bluetooth device) functioning in accordance with the Blue tooth standard, which is used to operate a universal one To ensure serial bus, in particular the connection of the power saving modes Sniff, Park and Hold according to the Bluetooth standard on the one hand and the power saving mode Suspend according to the USB standard on the other hand, the following conditions according to the invention

I _Suspend = I _{Bth_min} + (625 µs / (t _{HF_Ruhe} + 625 µs)). I _{HF_aktiv} ≦ 2.5 mA (high-power)

I _Suspend = I _{Bth_min} + (625 µs / (t _{HF_Ruhe} + 625 µs)). I _{HF_aktiv} ≦ 0.5 mA (low-power)

met, with with
I _Suspend : = Permitted maximum current in suspend mode on the USB
I _{Bth_min} : = Minimum necessary / possible current for process activity of the Bluetooth device in energy saving mode
t _{HF_Ruhe} : = time period for switched off transmitter or receiver (t ₁ - t _resting = t _{HF_Ruhe} )
625 µs = I _{HF_active} for Bluetooth
I _{HF_Aktiv} : = current requirement for active HF part (t ₂ - t ₁ )
are defined.

Since, according to the USB standard, two device classes are distinguished based on their power consumption, two cases must be distinguished for the condition to be complied with. If USB devices with high power consumption (high-power USB device) are to be connected, a high-power USB port will be used and, according to the USB standard, the suspend current I _Suspend ≦ 2 applies. 5 mA (see formula "high-power"), USB devices with low power consumption (low-power USB device) are connected, a low-power USB port is used and it applies to the USB standard Suspend current I _Suspend ≦ 0.5 mA (see formula "low power").

In order for the required condition for the current consumption to be met during the suspend mode, the average power consumption (I) of the connected Bluetooth device / s during the suspend mode is that

• a) the maximum current consumption on average 2.5 mA (high-power) or may not exceed 0.5 mA (low power),
• b) individual current peaks must not be longer than 1 ms, however, the maximum current consumption for high or exceed low-power USB devices,
• c) After a current peak, the maximum suspend current I _Suspend (2.5 mA or 0.5 mA) must be reached again or below.

Therefore, a Bluetooth device (master or slave) is not allowed send and never receive, because when switched on Sending or receiving operation a high probability for there is a violation of USB compliance.

For this reason, the high-frequency part (transmission / Receiving part) of the Bluetooth device at least partially and / or at least temporarily switched off and the function lity of the remaining functional units (baseband) in Bluetooth device limited so far that the entire Current consumption not greater than 2.5 mA (high power) or 0.5 mA (low power) for the Bluetooth device.

According to the condition mentioned above, a maximum current consumption by the Bluetooth device for suspend mode is based on a base load I _{Bth_min} (this results in the minimum current requirement I _min shown in the figure, which flows at the USB port) is then only in the minimum requirements and functions of the Bluetooth device are met and a with mean value ((625 microseconds / (t _{HF_Ruhe} + 625 microseconds)). I _{HF_aktiv)} for the Stromaufnah me the high frequency part RF portion, wherein in the in the figure shown current curve the time of the suspend mode in the interval [t ₂ . .t _rest ] falls and the time of the switched-off high-frequency part t _{HF_Ruhe results} from t ₁ -t _rest .

In the interval [t ₂ . .t ₁ ] the high-frequency part is active, since data is received via the receiver R _x , which results in the maximum current requirement of the Bluetooth device I _max , since the current requirement of the HF part I _{HF_Aktiv is} added to the base load I _min . It is quite conceivable that the suspend mode continues beyond time t ₂ if the limit for the suspend current (0.5 mA for low power; 2.5 mA for high power) is determined by the maximum current I _{max is} not exceeded or it is not exceeded for longer than 1 ms, otherwise the USB port returns to normal operation.

It must also be taken into account that for the hold, Sniff or park mode means that only one functions as a slave Bluetooth device can fall into one of these modes. On A Bluetooth device that functions as a master can only be used as long stay in a power saving mode until the last slave is gone delt and a synchronization with waking up first the slave can take place.

This procedure prevents the inadvertently reaching the Normal operation, with the general control of the adjustment and thus the sequence of both the individual power saving modes according to Bluetooth standard as well as the power saving mode according to USB Standard is done either by USB or Bluetooth.

Furthermore, it is also an unwanted he for adaptation range of Suspend mode, which is only achieved with USB if there is no data traffic for a period of 3 ms the USB interface (port) is available.

For this purpose, according to the invention, at regular intervals (<3 ms) in which the sequential control of a desired normal operation  goes out, dummy or pseudo data to the USB or USB port placed.

Claims (5)

1. Method for operating a short-range radio transmitter / receiver, in particular "Bluetooth" device, on a universal serial bus "USB" with the following features:

• a) During normal operation of the short-range radio transceiver, pseudo data are transmitted to the USB in periods in which no user and / or control data reach the USB via the short-range radio transceiver.
• b) during a power saving mode of the USB, individual functional units of the short-range radio transmitter / radio receiver are at least partially switched off.

2. The method according to claim 1, characterized in that a transmission / reception part of the Short-range radio transmitters / receivers at least is temporarily switched off. 3. The method according to claim 2, characterized in that a total current (I) is provided during the power saving mode, which is the sum of a minimum current (I _{Bth_min} ) necessary for the remaining functional _units and an average value for the current consumption of the transmission / Receiving part, may not exceed. 4. The method according to claim 3, characterized in that

• a) the total current (I) according to the formula
  I = I _{Bth_min} + (t _{HF_Aktiv} / (t _{HF_Ruhe} + t _{HF_Aktiv} )). I _{HF_aktiv}
  is set, where
  I: = total current during power saving mode
  I _{Bth_min} : = minimum _current
  I _{HF_active} : = current consumption of transmitting / receiving section
  t _{HF_Ruhe} : = time period of inactive transmitting / receiving part
  t _{HF_Aktiv} : = duration of active transmitting / receiving part
  are defined
• b) the total current (I) must not exceed a maximum current permitted for the power saving mode of the USB.

5. The method according to any one of the preceding claims, characterized characterized in that the pseudo data in discrete time be sent repeatedly.