This application relates to and claims priority from Japanese Patent Application No. 2009-277142 filed on Dec. 7, 2009, the entire disclosure of which is incorporated herein by reference.
The present invention relates to a module for use in a mobile communication terminal and a mobile communication terminal applying the same therein. And, in particular, it relates to the module for use in a mobile communication terminal, being compatible with a wireless communication system, such as, a WCDMA method or a LTE method, etc., for example, and the mobile communication terminal applying the same therein.
For a mobile phone, various studies are made on new methods, such as, the LTE method, etc., other than the WCDMA method, which was already put in a practical use thereof. With the WCDMA method and the LTE method, because of simultaneous operation of transmission and reception, they operate in different bands of frequencies, when transmitting and when receiving, for example. In those methods, a DPX (Duplexer) filter is used for separating the transmission band and the reception band.
As a technology for improving the performances of the DPX filter, there is already known that of applying a feed forward technology therein, as described in the following Non-Patent Document 1. In that Non-Patent Document 1 is disclosed a method relating to suppression of reception band noises on the transmission side, in which the feed forward technology is applied therein. For canceling the reception band noises of a narrow band, 869-894 MHz, corresponding to “Band 5” of the WCDMA method, a feed forward loop is constructed with a notch filter and a gain & phase adjusting functions.
[Non-Patent Document 1] IEEE Transaction on Microwave Theory and Techniques, Vol. 53, No. 1, January 2005 “Adaptive Duplexer Implemented Using Single-Path and Multipath Feedforward Techniques With BST Phase Shifter”.
In the Non-Patent Document 1 mentioned above, because of an object to cancel only the reception band noises of the narrow band, no particular consideration is paid, in relation to a delay on a feed forward path. Also, no particular consideration is paid upon, also about a power consumption of the feed forward loop.
With the WCDMA method and the LTE method, “Band 1” to “Band 17” (3GPP V8.2.0, a frequency-divisionmultiplex system) is defined, and the number of the bands is in a direction of increasing, further, in the future. For the purpose of dealing with those multi-bands, it is effective to make a frontend portion small in sizes thereof, by bringing the DPX to be tunable.
However, if constructing the DPX with a variable filter, because a degree of suppression of a high-level transmission signal on the transmitter side and/or a degree of suppression of reception band noises on the transmitter side are/is lowered down, it comes up to be a problem that noises leaking from a transmitting system to a receiving system affect ill influences upon the receiving characteristics of a mobile communication terminal. Further, in such case, it is also a problem to suppress an increase of the power consumption down to the minimum.
An object, according to the present invention, is to provide a module for use in a mobile communication terminal, being small in sizes and high in reliability and further operable with plural numbers of bands, in particular, in the module for the mobile communication terminal of conducting the simultaneous operation of transmission and reception, with using different frequency bands when transmitting and when receiving, and also a mobile communication terminal applying the same therein. Further other object of the present invention is to suppress an increase of the power consumption down to the minimum, in such case.
For dissolving the problems mentioned above, according to the present invention, there is applied the structure as described in the pending claims, as an example. In more details, for example, there is provided a module for use in a mobile communication terminal, for executing transmission/reception simultaneous operation, with using different frequency bands as transmission frequency and reception frequency, comprising: a filter having variable characteristics, which is configured to separate a transmission signal and a reception signal, and configured to pass frequency signals in plural numbers of bands therethrough, selectively; and a jamming signal cancel portion, which is configured to cancel the transmission signal and noises of reception band on the transmission side by a predetermined amount thereof.
According to the present invention, it is possible to provide a module for use of a mobile communication terminal, being small in sizes and high in reliability, and enabling with plural numbers of bands, and also a mobile communication terminal with using the same therein.
Those and other objects, features and advantages of the present invention will become more readily apparent from the following detailed description when taken in conjunction with the accompanying drawings wherein:
Hereinafter, embodiments according to the present invention will be fully explained by referring to the attached drawings.
First of all, explanation will be given on a flow of signal. A transmission signal 28 to be outputted from a modem (a modulator/demodulator) block 15 is amplified within a PA (Power Amplifier) 3, to be inputted to a transmission input terminal 25 of a DPX (Duplexer) 2, and it is outputted from an antenna-side terminal 26 of the DPX 2, extracting a transmission signal band through a filtering process, and it is outputted as a transmission signal of a terminal, from an antenna 1.
On the other hand, the reception signal received by the antenna 1 is inputted from the antenna-side terminal 26 of the DPX 2, and is outputted from a receiving output terminal 27 of the DPX 2, extracting a reception signal band therefrom through a filtering process, and then it is inputted to the modulated/demodulated signal processor block 15 through a LNA (Low Noise Amplifier) 4 as a reception signal 29. Within a RF signal processor block 16 of the modulated/demodulated signal processor block 15, the reception signal 29 is converted into a reception base-band signal 31, to be inputted into a base-band signal processor block 17, and at the same time, a transmission base-band signal 30 is converted on the frequency thereof, into a transmission signal 28. Within the base-band signal processor block 17 of the modulated/demodulated signal processor block 15, a transmission base-band signal 30 is produced in a Tx signal producing/mapping block 24, while a reception base-band signal 31 is demodulated in a demodulator block 18. Within the modulated/demodulated signal processor block 15 are stored transmission signal level information 21, reception signal SN information 22, and CQI (Channel Quality Information) information 23. The transmission signal level information 21 is produced from an output detection level 32 of PA 3 and/or transmission signal control information from a base station, which is included in the reception signal, etc. The reception signal SN information 22 and the CQI information 23 are produced from an error rate when demodulating the reception signal within the demodulatorblock 18, etc. The DPX2 is frequencyvariable for enabling to transmit/receive plural numbers of Bands, and controls the frequency upon basis of a control signal 37.
The DPX 2 is constructed with, as is shown in
In general, for the purpose of maintaining sufficient selectivity, the Rx filter 34 and the Tx filter 35 are constructed with SAW filters, etc., and are used as fixed frequency filters.
In the present embodiment, a frequency-variable filter is used as the DPX. For example, there is used a filter having such variable characteristics that the frequency signals of the Band 1 and the Band 2, having the characteristics shown in
Then, according to the present embodiment, as is shown in
A jamming wave canceller within the front end portion is constructed with a feed-forward loop of a coupler 5 for distributing the transmission signal of an output of the PA 3, thereby inputting to the jamming wave canceller 7, the jamming wave canceller 7, and a coupler 6 for composing an output of the jamming wave canceller 7. The jamming waves to be cancelled by this feed-forward loop are transmission signals, leaking from the transmitting system through the DPX 2, and also noises of the reception signal band leaking from the transmitting system through the DPX 2 into the receiving system.
The jamming wave canceller 7 is constructed with an amplitude adjuster 8, a phase adjuster 9 and a delay adjuster 10. With those adjusting mechanisms, signals of reverse phases are produced, with equal amplitudes to the transmission signal leaking through the DPX 2 and the noises of the reception signal band, and are composed within the composer 6; thereby canceling the jamming waves. Result of calculation about to what extent of the performances is required on the amplitude, the phase and the delay error of the jamming wave canceller 7, are shown in
In this manner, because of necessity of an error of high accuracy, each adjusting mechanism is that of a method of managing the error under control from the modulated/demodulated signal processor block 15. In more details, adjustments are made on the amplitude adjuster 8 by a control signal 11, on the phase adjuster 9 by a control signal 12, and on the delay adjuster 10 by a control signal 14, respectively, so that SN of the reception signal detected by the modulated/demodulated signal processor block 15, for example, comes up to the maximum.
On the other hand, the time when the jamming canceller 7 is necessary is only when the level of the transmission signal is high. For this reason, for achieving a low power consumption, such ON/OFF control is made on the jamming wave canceller 7 that it turns ON, by a control signal 13, only when the level of the transmission signal is high.
The distortion canceller block 19 within the base band portion is a block for canceling a 2nd order distortion component, which is generated within the LNA 4 and/or the RF signal processor block 16 when the transmission signal leaking from the DPX 2 is high. The transmission signal, as a cause of reason of the distortion, is the signal, which is produced within the base-band signal processor block 17, and it is already known, and since the signal 20 is equal to the transmission signal 30, it is possible to cancel the distortion component, i.e., producing the 2nd order distortion component by squaring the signal 20 and composing it to the distortion component included in the reception signal in the reverse phase thereof within the distortion canceller block 19. When composing, an adjustment of the distortion canceller block 19 is made, in such a manner that the S/N of the reception signal detected within the modulated/demodulated signal processor block 15 comes to the maximum, for example.
As was mentioned above, according to the present embodiment, for the purpose of maintaining the suppression degree of the transmission signal and the noises of the reception band on the transmission side, canceling of the transmission signal and/or the noises of reception band on the transmission side is made with using a feed forward technology. In this instance, for achieving cancellation of the signals of wide band, from the transmission signal to the reception band, within the feed forward loop is applied the delay adjusting function, in addition to the gain and the phase adjusting functions. And also, for achieving a stable cancellation of the jamming signals, control is made on the gain, the phase and the delay of the loop with using the reception SN and CQI (Channel Quality Information), etc. Further, for achieving the low power consumption, the feed forward loop can be turned ON/OFF.
Also, according to the present embodiment, small-sizing of the terminal can be obtained by making the DPX 2 operable corresponding to variable frequencies, and also the shortage of the suppression degree of the jamming waves is filled up by the jamming wave canceller and the distortion canceller, therefore there can be obtained an effect also on the low power consumption by turning ON/OFF the jamming wave canceller depending on the level of the jamming waves.
With the embodiment 1 shown in
With the present embodiment, other than the effect similar to that of the embodiment 1 shown in
Although explanation of the details thereof will be omitted, but the variable DPX 2 can be achieved by exchanging “C” of a multi-stage filter with using a variable capacity diode, etc. Also, the amplitude adjuster 8 is a gain control amplifier, which is usually applied, and it can change current of the amplifier or adjust the amplitude by switching over a load resistance. The phase adjuster 9 can make the phase adjustment by changing “C” of a LC ladder type circuit, which is usually applied, by a variable capacity diode, etc. Also, the delay adjuster 10 can be easily achieved by adjusting the delay with using a filter having the similar structure to that of the variable DPX, or switching over “L” of the LC ladder type circuit with using a switching diode, etc.
As was shown in the present embodiment, with conducting the signal processing by dividing into two (2) band groups, it is possible to achieve necessary performances, as is shown in
However, the present invention should not be limited to the embodiments mentioned above, but may include various variations thereof. For example, the detailed explanation was given on embodiments mentioned above for easy understanding of the present invention, then the present invention should not be restricted to that having all of the constituent elements explained in the above. Also, a part of the structure of any embodiment can be substituted by the structure of other embodiment, and the structure of other embodiment can be added to the structure of a certain embodiment, etc.
The present invention may be embodied in other specific forms without departing from the spirit or essential feature or characteristics thereof. The present embodiment(s) is/are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the forgoing description and range of equivalency of the claims are therefore to be embraces therein.
Number | Date | Country | Kind |
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2009-277142 | Dec 2009 | JP | national |