Matching circuit for adaptive impedance matching in radio devices

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to circuits for adaptively matching impedance in radio devices.

BACKGROUND

Radio devices are commonly used in wireless notebooks, wireless consumer electronics devices such as mobile telephones and the like, to provide wireless network connectivity. For the purposes of this document, the impedance of the radio antenna can be changed if the user touches the device by hand or under the influence of other nearby objects that could adversely affect the operation of the radio.

Also within the meaning of this document, preferably not easy to find a solution for vysheoboznachennyh problems, and make it so that it is suited not only for half-duplex mode, in which the change in the impedance of the antenna receiving apparatus does not necessarily affect the operation of the transmission device, but also duplex mode, whereby the antenna impedance change typically affects the operation of the transmitting device.

Disclosure of invention

The system includes a transceiver that communicates with an antenna and a matching network, through which communication channel between the antenna and transceiver. The matching network includes at least a first set of matching elements switchable from a first configuration in which at least a first matching element of a set is out of the communication channel, and a second configuration in which through the first matching element passes channel . The processor controls the matching network to produce first and second configurations and to determine first and second respective measures of performance. Processor forms the configuration having the best measures of performance.

Matching elements may be capacitors, inductors and resistors. In some embodiments, evaluation criteria for a received signal strength indicator (RSSI), namely, the average RSSI.

In some examples, it provided that the system can function, at least in the first and second frequency bands. In this case the matching network can include at least a second set of matching elements, the first set of matching elements selected processor when the system operates in the first frequency band and the second set of matching elements selected processor when the system operates in the second band frequencies.

The transceiver device can be adjusted, as described in more detail below, for the first and second configurations to facilitate full duplex operation during use of the matching network. A set of matching elements can form a π-shape, T-shape or an L-shaped configuration, and present principles may be used, without limitation, to personal communications (PCS), TDMA, GSM, Edge, UTMS, CDMA 1x-RTT, 1X -EVDO, 802.11a, 802.11b, 802.11g, 802.11n, Wimax, LTE.

In another aspect, a system includes a transceiver that communicates with the antenna. Transceiver includes a receiver and a transmitter. After matching circuit TRD communication channel extends between the antenna and transceiver. The matching circuit includes a first set of matching elements switchable from a first configuration in which at least a first matching element of a set is out of the communication channel, and a second configuration in which the first matching element via the communications channel passes. The processor controls the matching circuit to form first and second configurations and to determine first and second respective measures of performance. Processor forms the configuration having the best measures of performance. The transceiver device may be configured for use with a matching circuit so that the matching circuit is used in full duplex mode.

In another aspect, the method consists in determining whether a receiving device performance indicator threshold. Only if the index does not correspond to the threshold values, the method includes forming multiple configurations for an impedance matching circuit to interact with the radio antenna and determines the index of the receiving device efficiency for each configuration. The method includes forming one of the configurations in circuit based on the determination indicator of the effectiveness of the receiving device.

The formation of several configurations can only be done if the receiving device does not perform an active data session. Also, the regulation of the transmission device associated with the receiving device, may be performed for the effect of the impedance matching circuit. Additionally, the method may also be in non-limiting examples, in determining a modulation currently used for communication with the receiving device, wherein thresholds depend on the currently used modulation.

Details of the present invention, both in terms of its structure and its use will be more apparent in view of the accompanying drawings, in which like numerals indicate similar numbers and wherein:

BRIEF DESCRIPTION OF DRAWINGS

1 shows a block diagram of an exemplary radio with the present matching circuit;

2 is a block diagram of a typical matching circuit in accordance with the principles of the present invention;

3 shows a timing diagram of exemplary logic implemented in a matching circuit;

4 is a diagram of a lookup table of thresholds; and

Figures 5-7 show alternative matching circuits.

EMBODIMENTS

The radio 10 of Figure 1 which can be built into the portable electronic device 11, such as a portable computer or wireless telephone includes an antenna 12, transmitting and receiving signals from a matching circuit 14, an example of which is described below with reference to Figure 2. . The matching circuit 14 may be connected to one or more filter components, such as duplex antennas. In the example shown the matching circuit 14 communicates with the antenna 16, duplex cellular antenna 18, duplex personal communications (PCS), as well as with standard duplex antenna "long term evolution» (LTE) or the switch 20 transmit / receive (T / R).

In turn, interact with the components 16-20 the receiver / downconverter 22 of radio-frequency (RF) transceiver 24. The receiver / downconverter converts the RF signals to intermediate frequency (IF), which is sent to the IQ demodulator 25 (coincidence in phase / phase shift of 90 degrees) of the receiving device of the main processor 26 for demodulating the IF in the main frequency band processed by the main processor.

In the apparatus disclosed up to now also has a transmission part, namely the CPU 26 has IQ modulator 28 of a transmitter for modulating baseband signals to IF, which are upconverted to the RF up converter 30 transceiver 24. In considering three schemes transmission in the form in which they are shown in a non-limiting example of Figure 2, the upconverter 30 sends RF signals to a cellular filter 32 which communicates with the cellular radio amplifier output 34, which in turn may be coupled to the directional coupler 36 cellular. The directional coupler 36 communicates with the cellular antenna 16, duplex mobile communication, as shown.

Also upconverter 30 sends RF signals to a PCS filter 38, which interacts with the radio amplifier power PCS 40, which in turn can interact with the directional coupler 42 PCS communications. The directional coupler connection 42 communicates with the PCS shown duplex antenna 18 PCS. In the example shown in Figure 2, the upconverter 30 sends RF signals to a LTE filter 44, which interacts with the LTE radio amplifier output 46, which in turn can interact with the directional coupler 48 LTE communication. The directional coupler 48 LTE connection interacts with the displayed duplex LTE antenna switch 20 or the transmit / receive. If desired, all three couplers connection 36, 42, 48 may interact with each other, and at least one communications coupler 48 may interact with a powerful detector 50 transceiver 24 for a purpose which will shortly be disclosed.

Completing the description of Figure 1, main processor 26 may use a switch control register or I / O device 52 for configuring the matching circuit 14 in accordance with the principles described below. Also, processor 26 may access a memory such as disk memory or solid state memory, such as flash memory 54, which may be stored, inter alia, look-up table, described in more detail below.

Figure 2 shows a typical detail matching circuit 14. The matching circuit 14 may be only one set of matching elements but in the example shown in the matching circuit 14 has three sets 56, 58, 60 of matching elements 62, each set communicates with a corresponding duplex antenna 16-20, as shown. The switch 64, controlled by the processor 26 determines which set 56-60 of matching elements communicates with the antenna 12. It is obvious that the CPU 26 appropriately configures switch 64 for the particular mode that uses the radio 10. Thus, it is possible to avoid lengthy and relatively a bulky set of matching elements, since the respective sets 56-60 of matching elements can be advantageously smaller sized since they are configured on the frequency range to which they correspond, eg cellular band, PCS, or LTE.

In the example shown in Figure 2, the matching elements in a single set are capacitors which are connected with each other in parallel as shown, forming a π-shaped configuration. Alternatively can be used a T-shaped or L-shaped configuration matching elements, as described in more detail below with reference to Figures 5-7. Instead of capacitors, use may be preferably less inductors or resistors. Each set 56-60 of matching elements may be grounded as shown by respective opposing inductors "I". If necessary, inductors "I" may also be connected to or disconnected from the circuit in the configuration of the matching circuit 14.

Typical logic processor 26 in configuring the matching circuit 14 is shown in Figure 3. Beginning at step 66 the power supply and the connection to the network, in some embodiments, the logic may move to decision step indicated by diamond 68 to determine whether to pass a radio 10 active call or other data transmission. Also, it may be manufactured by resetting the counter "n".

If there is current session logic may move to block 70 to bypass the process described below the settings until the session and formation default configuration for the network of matching elements in the matching circuit 14. In other embodiments the tuning process may take place regardless of whether the session is active.

In the following example, the absence of active sessions (either immediately after the power supply when the test session is active in the diamond 68 decision is not carried out), the logic moves to block 72 to test the performance criteria. In one embodiment, the processor 26 determines received signal strength indicator (RSSI) in the transceiver. Other embodiments may employ other measures of performance, such as signal / noise ratio, bit error rate, etc.

Also at block 72 the processor 26 determines the current modulation protocol used. In the example of figures 1 and 2 the current protocol is cellular, PCS, or LTE.

Next, in box 74 decision processor 26 determines whether the penalized criterion measures (for example, RSSI) threshold sensitivity for the modulation protocol used. This may be done by accessing the memory 54 to be inserted into lookup table pore RSSI values ​​for the current modulation protocol in use. EXAMPLE tables discussed later with reference to Figure 4. If necessary browsable thresholds can be compared with the current instantaneous RSSI values, but in the example shown in Figure 3, processor 26 calculates the average RSSI value on the basis of multiple cycles, such as two or more and compares the average actual RSSI value with the threshold values ​​of rhombus 74 decisions.

If the actual RSSI value is not inconsistent with the threshold values, in certain embodiments, to avoid excessive processing the logic may move to decision making a diamond 76 to determine whether the number of recent RSSI calibration in box 74 the decision-making threshold value 2. If e.g. do not match, then "n" is incremented at block 78, and the logic returns back to block 72. On the other hand, if "n" meets the threshold value, then the logic proceeds to block 70.

If the RSSI value does not correspond to the threshold value of the rhombus 74 decision, in some embodiments, the logic may include additional checks in box 80 the decision-making in order to determine to see if the gain of a low noise amplifier (LNA) of the receiving device to the maximum value , by setting it to the maximum value in block 82, if it has been set. In any case, the setting of the selected set 56-60 of matching elements 62 in the matching circuit 14 begins at block 84 where the first matching element 62 is switched into the circuit and RSSI recorded at block 86, then the second element, and so on, is recorded RSSI values, by as matching elements gradually, one included in the circuit. If desired, in less preferred embodiments, are gradually switched from two or more member 62. After all matching elements 62 are appropriately incorporated in the control unit 88 selects the configuration with the highest RSSI. Thus, for example, if the first three elements 62 provide the highest RSSI, then to a matching circuit 14 in block 88, this configuration is selected. The method ends in step 89.

4 shows a representative, non-limiting lookup table 90 that may be stored on the medium 54 and used at block 74.

These guidelines suggest their use in a number of communication protocols including but limited to, personal communications (PCS), TDMA, GSM, Edge, UTMS, CDMA 1x-RTT, 1X-EVDO, 802.11a, 802.11b, 802.11g, 802.11n, Wimax, LTE. Also, these principles suggest their use in half-duplex and full-duplex operation, and in the latter case, deterioration in the quality of transmission is avoided by the inclusion of a standard program adjust the transmitting device the effect of the matching circuit 14.

In particular, when adjusting the transmission apparatus, the above matching elements are included in the receiver circuit on and off of the circuit in various combinations, singly or in groups. This makes it possible to change the impedance of the transmission device, which in turn may affect the power output of a transmitter gain side radio etc. Accordingly, to optimize the operation of the transmitter, while adjusting the transmitting device is configured for each combination of matching elements. Transmitter circuit can be configured by setting a particular gain, input power, etc. for each of the impedance formed by the combination of matching elements. Parameters transmitter for each impedance may be stored in a calibration table to which access can be performed during operation so that the matching elements in the receiving device included in the circuit on and off from the circuit as described above, the parameters of the transmission device corresponding to a certain impedance change for optimize the performance of the transmitting device.

5 shows a T-shaped matching circuit 100 in which two sets 102, 104 of matching elements are connected to a common cross line 106, one end of which is connected to the switch and the other end connected to the duplex antenna switch or transmission / reception. 6 and 7 are L-shaped circuit in which the matching circuit 108 is connected to the cross line 110, which in turn is connected to a duplex switch and the antenna switch or the transmit / receive as shown. The difference between Figures 6 and 7 is that in Figure 6 intersects the line 110 is grounded through the inductor 112 from the duplex antenna / switch transmission / reception, whereas in Figure 7 it is grounded through the inductor 112 from the switch.

Although herein specific for the adaptive matching circuit matching the impedance in the radio has been shown and described in detail, it should be understood that the subject matter provided by the present invention is limited only by the claims.

For example, the matching circuit 14 may be completely or partially moved to a chip transceiver device. In addition, the logic of Figure 3 can be completely or partially implemented as part of a standard computer program.