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Orthogonal frequency division multiplexing receiving device

A receiving device and antenna technology, which is applied in the directions of orthogonal multiplexing system, multiplexing communication, space transmit diversity, etc., can solve the problems of unreceived, low receiving position, and relay fading receiving environment, etc., to achieve improved Adaptability, the effect of reducing the circuit structure

Inactive Publication Date: 2008-07-02
MEGACHIPS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Also, in the case of a portable device antenna, its receiving position is generally low
Therefore, the tolerance for changes in receiving sensitivity is small, and sometimes even a small change in the receiving position becomes unreceivable
[0005] (2) Since portable devices are used while moving, the reception environment is prone to relay fading

Method used

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  • Orthogonal frequency division multiplexing receiving device
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  • Orthogonal frequency division multiplexing receiving device

Examples

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Effect test

no. 1 Embodiment

[0057] FIG. 1 is a functional block diagram of an OFDM receiving apparatus according to a first embodiment of the present invention. The OFDM receiving device of this embodiment is a receiving device that can be used in portable equipment such as a mobile phone, a portable digital television, etc., and can receive a layer consisting of only one segment from an OFDM signal composed of multiple layers. device. Then, the OFDM receiving apparatus of this embodiment is a receiving apparatus having two directional antennas 11A and 11B as shown in FIG. 1 and performing diversity reception.

[0058] The RF (radio frequency) signal sent by the OFDM transmitting device (not shown in the figure) is received by two receiving antennas through the transmission path. The received RF signal is output to the tuner 13 via the antenna switching unit 12, and frequency converted by the tuner 13 to become an IF (intermediate frequency) signal. This IF signal is output to an A / D converter through ...

no. 2 Embodiment

[0080] Next, a second embodiment of the present invention will be described. In the second embodiment, antenna switching control is performed based on the bit error rate (BER) of the received signal. Fig. 6 is a block diagram of an OFDM receiving apparatus related to the second embodiment. In the figure, the same structures as those of the first embodiment are denoted by the same reference numerals. Differences from the first embodiment will be described below.

[0081] As shown in FIG. 6 , this OFDM receiving apparatus has a judgment circuit 31 to which a bit error rate signal is input from an FEC circuit 19 . Specifically, the FEC circuit 19 corrects errors of the signal by viterbi decoding, but the viterbi decoding circuit counts the number of occurrences of bit errors that have occurred while performing error correction processing. Based on the count value, the FEC circuit 19 can calculate the bit error rate. Then, the bit error rate signal is output to the judging cir...

no. 3 Embodiment

[0085] Next, a third embodiment of the present invention will be described. In the third embodiment, switching of antennas is controlled based on the C / N ratio (Carrier to Noise ratio) of the received signal. Fig. 7 is a block diagram of an OFDM receiving apparatus related to the third embodiment. In the drawings, the same structures as those of the first embodiment are denoted by the same reference numerals. Differences from the first embodiment will be described below.

[0086] As shown in FIG. 7 , this OFDM receiving apparatus is provided with a C / N calculation unit 41 which calculates the C / N ratio of the received signal based on the calculation result of the FFT circuit 16 . The C / N ratio is the ratio of signal to noise, and the higher the value, the stronger the signal power. In addition, the C / N calculation unit 41 may calculate the C / N ratio using the signal before the FFT calculation. Then, the C / N calculation unit 41 outputs the C / N ratio signal of the received s...

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Abstract

An OFDM receiver apparatus for performing a diversity reception, wherein the power consumption and the cost can be reduced. An OFDM signal transmitted from a transmitter apparatus is received by two antennas (11A,11B). An antenna switching part (12) selectively outputs the signal, which was received by one of the two antennas, to a tuner (13). A signal outputted from the tuner (13) is supplied through an A / D converter (14), a quadrature detecting circuit (15) and through an FFT calculating circuit (16) to an equalizing circuit (17). A deviation determining circuit (21) calculates the positional deviations, on the constellation, of I and Q component signals outputted from the equalizing circuit (17). When the positional deviations exceed a predetermined threshold value (when the positional deviations of the signals are large), a deciding circuit (22) sends, to the antenna switching part (12), a control signal that instructs it to switch to the other antenna.

Description

technical field [0001] The present invention relates to diversity reception technology of Orthogonal Frequency Division Multiplexing (OFDM) signal. Background technique [0002] In Japanese terrestrial digital television broadcasting, OFDM (Orthogonal Frequency Division Multiplexing) is used as the transmission method. The OFDM method is a multi-carrier transmission method that divides the transmission signal into multiple carriers for transmission. , has the advantages of strong frequency selective fading of multipath transmission, the frequency spectrum of each sub-channel can be closely configured, and the frequency utilization efficiency is high. [0003] In addition, terrestrial digital TV broadcasting (1-segment broadcasting) is expected to start on portable devices in the future. When designing portable telephones and card-type digital TV receivers that can receive digital TV, it is usually necessary to consider miniaturization and power consumption reduction. In ad...

Claims

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Application Information

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IPC IPC(8): H04B7/08H04J11/00
Inventor 陈寒达田向健吾
Owner MEGACHIPS
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