Abstract:
A multi-antenna receiver using single tuner and method thereof are disclosed. By using single tuner, a multi-channel switch, a demodulator and an antenna-selecting mechanism, the receiver will be able to choose a signal, whose quality can meet the quality requirement, from multiple signals received by multiple antennas. By the present invention, not only the quality requirement for the received signals is met, but also the circuit size and the power assumption of the multi-antenna receiver are reduced.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of Invention 
         [0002]    The present invention generally relates to a multi-antenna communication receiver, and more particular, to a wireless communication receiver using a single tuner. 
         [0003]    2. Description of Related Art 
         [0004]    With the conventional manner of receiving wireless signals by a single antenna, the user often needs to adjust the position and orientation of the single antenna to improve the quality of received signals when the reception quality is not satisfied. As a result however, it causes a lot of inconvenience to the user. In the case where it is not easy to change the position and orientation of the antenna as desire, the single antenna architecture would have low signal reception quality, which is counted as the drawback of the single antenna architecture. 
         [0005]    To overcome the above-described problem, in a wireless communication, for example, in a digital video broadcast-terrestrial system (DVB-T system), multiple antennas are used to enhance the reception efficiency, which is termed as antenna diversity. With the antenna diversity scheme, the receiver is equipped with two or more antennas for receiving the signals. It is assumed that the antenna diversity herein includes N pieces of antennas (N is an integer greater than 1).  FIG. 1  is the block diagram of a conventional wireless communication receiver using the antenna diversity scheme. Referring to  FIG. 1 , multiple antennas  101 - 1 ˜ 101 -N are respectively one-to-one coupled to the corresponding tuners  103 - 1 ˜ 103 -N. The output signals of the tuners can be intermediate frequency (IF) signals or inphase/quadrature (I/Q) signals. The outputs of the tuners are coupled to a combiner  105 , which is responsible for respectively weighting the different signals received by the antennas and combining the weighted signals. The output from the combiner  105  is coupled to a demodulator  107 , and the demodulator  107  outputs a transport stream (TS) to a decoder (not shown in  FIG. 1 ) for decoding. 
         [0006]    It can be seen from the above described, a receiver adopting the above-mentioned antenna diversity scheme requires a plurality of tuners, which would increase the circuit complexity. In addition, the scheme employs a plurality of components, which costs more, requires a bigger printed circuit board (PCB) area and consumes more power. Therefore, the relevant prior art is not suitable for an electricity-saving and portable device. 
       SUMMARY OF THE INVENTION 
       [0007]    Accordingly, an aspect of the present invention is to provide a multi-antenna wireless communication receiver using a single tuner, which is suitable for a wireless communication receiver, for example, a DVB-T receiver. 
         [0008]    Another aspect of the present invention is to provide a multi-antenna wireless communication receiver with low cost and less circuit area for effectively enhancing the coverage range. 
         [0009]    Another yet aspect of the present invention is to provide a multi-antenna wireless communication receiver suitable for a mobile electronic device or portable electronic device. 
         [0010]    To achieve the above-mentioned aspects, the present invention provides a wireless communication receiver, which includes a multi-channel switch (MS), a tuner and a demodulator. N pieces of antennas (N is an integer greater than 1) are coupled to the MS, and the MS selects one of the signals received by the antennas for output. The MS output is coupled to the tuner, while the output signal of the tuner can be an IF signal or an I/Q signal. The tuner output is coupled to the demodulator and the demodulator outputs a transport stream available for a next-stage decoder to decode. The demodulator can further feed a control signal back to the MS to select one of the signals received by the antennas. 
         [0011]    The demodulator is able to monitor bit error rate (BER) and, according to the detected BER, judges whether the quality of the signal received by the antenna the MS selects meets the quality requirement. For example, in DVB-T communication, the quality requirement can mean, but not limited to, that based on the transport stream output from the demodulator, the next-stage decoder may recover the originally transmitted frames. If it fails to meet the quality requirement, the demodulator would use the control signal to make the MS select the signal received by another antenna until the signal quality requirement is met. In order to select the quality-qualified signal received by an antenna, the MS would be controlled so that, for example but not limited to, the signals received by all the antennas may be sequentially selected. 
         [0012]    Further, the present invention provides a multi-antenna wireless communication receiving method using a single tuner. The method includes the following steps: selecting the default antenna by a MS to receive the signal; performing tuning and demodulating on the signal received by the antenna; continuously monitoring the quality of the received signal and judging whether the signal meets the quality requirement; if the quality of the received signal meets the quality requirement, keeping the signal received by the antenna to be use in decoding; if the quality of the received signal does not meet the quality requirement, controlling the MS to select signals received by other antennas. 
         [0013]    In summary, the present invention provides a multi-antenna wireless communication receiver using a single tuner and the method thereof, wherein the benefit of the proposed multi-antenna scheme with single tuner are closed to that of the prior multi-antenna scheme with multiple tuners. Moreover, the present invention is capable of reducing the receiver size and lowering the power-consumption of the receiver. Therefore, the present invention has overwhelming advantages for a wireless communication device to adapt the trend of portability, miniaturization and power-conservation. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
           [0015]      FIG. 1  is a block diagram illustrating a conventional wireless communication receiver. 
           [0016]      FIG. 2  is the block diagram of a wireless communication receiver according to a preferred embodiment of the present invention. 
           [0017]      FIG. 3  is the flowchart of the wireless communication receiving method according to the preferred embodiment of the present invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0018]    Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. 
         [0019]      FIG. 2  is the block diagram of a wireless communication receiver according to an embodiment of the present invention, which may be applicable in a DVB-T system. Referring to  FIG. 2 , the wireless communication receiver  210  includes a multi-channel switch (MS)  211 , a tuner  213  and a demodulator  215 , wherein the tuner  213  and the demodulator  215  are included in a network interface module (NIM)  217 . 
         [0020]    In addition, N antennas  201 - 1 ˜ 201 -N (N is an integer greater than 1) are coupled to the MS  211 , and the MS  211  selects one of the signals received by the antennas  201 - 1 ˜ 201 -N for output according to a control signal CTL come from the demodulator  215 . The output of the MS  211  is coupled to the tuner  213 , and the tuner  213  tunes the input signal and outputs the tuned signal. The output signal of the tuner  213  can be an intermediate frequency (IF) signal or an inphase/quadrature (I/Q) signal. The output of the tuner  213  is coupled to the demodulator  215  for performing a demodulating operation. The output of the demodulator  215  is a transport stream (TS) provided to a next-stage decoder (not shown in  FIG. 2 ) for decoding. The demodulator  215  can further feed the control signal CTL back, so as to control the MS  211  selecting one of the signals received by the antennas  201 - 1 ˜ 201 -N for output. 
         [0021]    The demodulator  215  is able to monitor bit error rate (BER). The detail implementation manner of the BER-monitoring function is not particularly specified herein, as long as the function works to achieve the goal of the present invention. The demodulator  215  judges whether the signal quality received by the antenna the MS  211  selects meets the quality requirement according to the detected BER. For example, in DVB-T communication, the quality requirement may mean, but not limited to, that based on the transport stream output from the demodulator  215 , the next-stage decoder (not shown in  FIG. 2 ) recover the originally transmitted frames. 
         [0022]    If the received signal from the selected antenna fails to meet the quality requirement, the demodulator  215  would use the control signal CTL to make the MS  211  select the signal received by another antenna until the signal quality requirement is met. In order to select the quality-qualified signal received by an antenna, the MS  211  would be controlled so that, for example, but not limited to, sequentially selecting the signals received by the N antennas may be selected in a sequence, from the first antenna  201 - 1 , then the second antenna  201 - 2 , until the N-th antenna  201 -N. 
         [0023]      FIG. 3  is the flowchart of the wireless communication receiving method according to the preferred embodiment of the present invention. Referring to  FIG. 3 , in the embodiment, a demodulator is used to monitor the received signal quality for judging whether the received signal meets the quality requirement so as to decide whether the MS needs to select the signals received by other antennas. The steps of the method are described as follows. 
         [0024]    First, the MS selects a default antenna to receive a signal (step S 301 ). 
         [0025]    Next, the received signal of the antenna is input to a tuner for tuning, followed by sending the tuned signal to the demodulator. The demodulator monitors quality of the received signal and judges whether the received signal meets the quality requirement (step S 303 ). For example, in DVB-T communication, the quality requirement may mean, but not limited to, that based on the transport stream output from the demodulator, the next-stage decoder may recover the originally transmitted frames. If the received signal meets the quality requirement according to the judgment of the demodulator, the selected antenna corresponding to the quality-qualified signal is kept in use for outputting signals for decoding (step S 305 ) and the procedure flow goes back to step S 303 . 
         [0026]    If the received signal fails to meet the quality requirement, it would be judged whether all the antennas have been selected by the MS (step S 307 ). If not all the antennas have been selected by the MS, the demodulator would control the MS to select other candidate antennas to receive the signal (step S 309 ) and the procedure flow goes back to step S 303 . 
         [0027]    If all the antennas have been selected by the MS, that is to say, the signal reception is failed (step S 311 ) and the procedure flow ends up. 
         [0028]    Once the received signals of all the antennas fail to meet the quality requirement so to recognize failure of the signal reception, the wireless communication receiver is able to restart the above-described procedure flow after a suitable interval. The detail implementation manner for deciding the suitable interval is not particularly specified, as long as the goal of the present invention is achieved. 
         [0029]    In summary, the present invention has the advantages, not only to gain the expected benefit of the multi-antenna scheme, but also to reduce the receiver size and lower the power-consumption of the receiver. Therefore, the present invention is applicable to a mobile multimedia device with a display unit, for example, a notebook computer, a portable television, a mobile phone handset, a digital camera, a digital camcorder, a vehicle television and a personal digital assistant (PDA). 
         [0030]    It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing descriptions, it is intended that the present invention covers modifications and variations of this invention if they fall within the scope of the following claims and their equivalents.