Data receiving apparatus

Data receiving device

The present invention relates to a data receiving device, in particular to a data receiving device of a PDC (Personal Digital Cellular) system using a TDMA (Time Division Multiple Access) system. The continuous receiving state in the device continuously receives one or more signals. Sub-frame period.

The received radio waves transmitted from the base station to the data receiving device via the propagation path are subject to fluctuations called fading. This fading is one reason for the deterioration of the quality of the received radio waves. Therefore, the effects of fading must be reduced to achieve high-quality radio wave transmission. One of the technical measures to reduce the influence of fading is the diversity receiving technology. In this technology, the effect of fading is reduced by using two or more receiving antennas that are set to leave a sufficient distance between each other. Therefore, since the fading effect on the input radio waves received by each receiving antenna is considered to be uncorrelated, the receiving antenna that inputs the received radio waves in the best receiving state is selected by switching between multiple receiving antennas, It is possible to reduce the effects of fading.

As shown in Figure 1, the data receiving device using this conventional selective diversity system includes a first receiving antenna 11 and a second receiving antenna 12 that are arranged to be separated from each other and leave a sufficient distance between each other. A receiver 13 and a second receiver 14, a selector 15 and a switching unit 16.

The radio waves received by the first antenna 11 are demodulated by the first receiver 13 and converted into first demodulated data. The first demodulated data is input to the switching unit 16. The first receiver 13 detects the signal strength received by the first antenna 11 and the detected received signal strength is input to the selector 15. On the other hand, the radio waves received by the second antenna 12 are demodulated by the second receiver 14 and converted into second demodulated data. The second demodulated data is input to the switching unit 16. The second receiver 14 detects the signal strength received by the second antenna 12 and the detected received signal strength is input to the selector 15. The selector 15 compares the received signal strength input from the first receiver 13 and the received signal strength input from the second receiver 14 and selects a receiver with a higher received signal strength. The switching unit 16 switches between the first demodulated data input from the first receiver 13 and the second demodulated data input from the second receiver 14 according to the selection result of the selector 15, and either one is switched by the switching unit 16 The demodulated data selected by the switching is output from the switching unit 16 via the output terminal 17. In this way, the comparison of the strength of the received signal by the selector 15 and the switching of the demodulated data by the switching unit 16 are realized on each symbol.

Next, the reception time stamp of this data receiving device will be explained by referring to FIGS. 2A to 2E. As shown in Figures 2A and 2B, when a signal subframe transmitted from a base station to a data receiving device is divided into three time periods, a time period of the signal subframe in the voice transmission of the ordinary PDC system is dedicated to the current reception time Marked data. On the other hand, in a PDC system where the continuous reception state lasts for one or more subframe periods, it may be that all three time periods of the subframe are used to align the data with the quasi-current reception time stamp. In the case where all three time periods of such subframes are used to receive time-stamped data, as shown in Figures 2B and 2E, each time period of each signal subframe sent through a forward channel is The data are arranged in order: guard time R (4 bits) for short-impulse transient response, paragraph head mark P (2 bits), control signal CAC (112 bits), synchronization word SW (20 bits), color code code CC (8 bits), control signal CAC (112 bits) and collision control bit E (22 bits). Thus, in the data receiving apparatus, data reception is performed from the operation time stamp shown in FIG. 2C. That is to say, in each time period, the synchronization capture is performed by using the synchronization word SW and the color code CC, and the data reception is performed at other time stamps. Furthermore, in the data receiving device, the selective diversity operation after detection is continuously performed through the data receiving period shown in FIG. 2D, so as to achieve demodulation of the data obtained by the continuous receiving operation.

However, using the above-mentioned conventional data receiving device, it is always necessary to put the two receiver systems into operation, and switch between the two receiving systems at each symbol, and also requires the selector and switching unit to continue its operation at each symbol. The corresponding operation at. As a result, power consumption has increased, and the circuit size and cost of the data receiving device have also increased due to the provision of two receiver systems.

The object of the present invention is to provide a data receiving device that can complete the selective diversity receiving operation with only a single receiver system, thereby correspondingly reducing the circuit size, cost and power consumption of the data receiving device.

In order to achieve the above-mentioned object, the data receiving device of the present invention is constructed so that it uses the synchronization word time stamp or the synchronization word and color code code two time stamps (when the received data has been aligned with the current reception mark, they are not synchronized capture The necessary two) perform antenna selection diversity operations, so that it is possible to obtain a diversity effect with only a single receiver system, and accordingly reduce the circuit size, cost, and power consumption of the data receiving device.

The first data receiving device of the present invention includes: a time stamp (which is not necessary for synchronization capture) of a plurality of synchronization words contained in a subframe of a received signal to compare multiple A comparing device for comparing the signal strength received by the receiving antenna; and a selecting device for selecting a receiving antenna with the highest received signal strength from a plurality of receiving antennas based on the comparison result of the comparing device.

Here, for the comparison device, it is also possible to compare multiple receiving antennas by using the time stamp of one color code of multiple color code codes contained in the subframe of the received signal (it is not the one necessary for synchronization capture). The signal strength received by each.

The second type of digital receiving device of the present invention includes: a plurality of receiving antennas for receiving radio waves; an antenna switching unit for switching between the plurality of receiving antennas; The radio wave received by one of the antennas demodulates data and detects multiple synchronization words by using one synchronization word time stamp (it is necessary for not performing synchronization capture) among multiple synchronization words contained in one subframe of the received signal. A receiver that receives the signal strength received by each antenna; and a receiver for controlling the operation of the antenna switching unit according to the signal strengths received by the multiple receiving antennas detected by the receiver so that the highest received signal can be selected from the multiple receiving antennas The strength of the receiving antenna selector.

Here, for the receiver, it is also possible to detect multiple receptions by using one of the multiple color code time stamps contained in one subframe of the received signal (it is not the one necessary for synchronization capture). The strength of the signal received by each antenna.

Fig. 1 is a block diagram showing the principle structure of a conventional data receiving apparatus; Figs. 2A to 2E are explanatory diagrams illustrating time stamps of data reception operations of the conventional data receiving apparatus shown in Fig. 1; Fig. 3 is a block diagram showing The principle structure of a data receiving device according to an embodiment of the present invention; FIGS. 4A to 4E are explanatory diagrams illustrating the time stamp of the data receiving operation of the data receiving device shown in FIG. 3.

Referring to FIG. 3, a data receiving device according to an embodiment of the present invention includes a first receiving antenna 1 and a second receiving antenna 2, an antenna switching unit 3, a receiver 4, and a selector 5. The first antenna 1 and the second antenna 2 are arranged to be separated from each other, leaving a sufficient space distance between them, and work to receive a radio wave emitted from a base station. The antenna switching unit 3 performs switching between the first antenna 1 and the second antenna 2 according to the control signal supplied by the selector 5, and selects any one of the first antenna 1 and the second antenna 2 by the switching made by the antenna switching unit 3. The out antenna is connected to the receiver 4.

The receiver 4 works to demodulate the radio wave data received by any one of the first antenna 1 and the second antenna 2 connected to it by the antenna switching unit 3, and detect the signal strength received by the first receiving antenna 1 and the second antenna. Receive the signal strength received by antenna 2. Meanwhile, the detection of the signal strength received by the first antenna 1 and the signal strength received by the second antenna 2 is performed by using the time stamp of one of the multiple synchronization words contained in the subframe of the demodulated data (it is not performed The one necessary for synchronous capture) is completed. For this purpose, the receiver supplies an instruction signal to the selector 5 at this time mark, allowing the selector 5 to control the antenna switching unit 3 so that the antenna switching unit 3 switches between the first antenna 1 and the second antenna 2, As a result, at least one of the two antennas is connected to the receiver 4. The selector 5 generates a control signal according to the command signal supplied by the receiver 4 and outputs the control signal to the antenna switching unit 3. In this way, the signal strength received by the first antenna 1 and the signal strength received by the second antenna 2 are successively received by the receiver 4 is detected. The selector 5 compares the signal strength received by the first antenna and the signal strength received by the second antenna (both have been detected by the receiver 4), and generates a control signal to be supplied to the antenna switching unit 3, so that The antenna switching unit 3 can select a receiving antenna with a higher received signal strength.

Furthermore, the first antenna 1 and the second antenna are detected by the receiver 4 by using the time stamp of the synchronization word among the plurality of synchronization words contained in the demodulated data subframe (it is different and necessary for synchronization capture). 2 At the same time as the signal strength of each received, it is also possible to use the multiple synchronization words and color code synchronization words and color code time stamps contained in the subframe of the demodulated data (both of which are not used for synchronization capture) The necessary one) performs detection of the signal strength received by each antenna.

Hereinafter, the receiving time stamp of the data receiving device of the current embodiment of the present invention will be explained with reference to FIGS. 4A to 4E. As described above, when one signal subframe transmitted from the base station to the data receiving device is divided into three time periods shown in FIGS. 4A and 4B, one time period of the signal subframe in the voice transmission of the ordinary PDC system is dedicated to Quasi-current reception time-stamped data. On the other hand, in a PDC system where the continuous reception state lasts for one or more sub-frame periods, the situation may be that all three time periods of the sub-frame are used to align the current reception time-stamp The data. In the case where all three time periods of this subframe are used to align the data of the current reception time stamp, as shown in Figs. 4B and 4E, each time period of each subframe of a signal sent through a forward channel The data are arranged in order: guard time R (4 bits) for short-impulse transient response, paragraph head mark P (2 bits), control signal CAC (112 bits), synchronization word SW (20 bits), color code Code CC (8 bits), control signal CAC (112 bits), and collision control bit E (22 bits).

The synchronization capture in the data receiving device can be accomplished only by using at least one synchronization word SW and at least one color code CC, and it is not required to use all three synchronization words SW and all three color code codes CC contained in one subframe. Therefore, in the case where the synchronous capture is performed through a synchronization word SW and a color code CC included in the first time period of each subframe, as shown in FIG. 4C, the data receiving device uses the first time period of each subframe to be executed. The synchronization word SW and the color code CC included are captured synchronously, and the antenna selection operation is performed at the time marks of the synchronization word SW and the color code CC contained in the last two time periods of each subframe (ie, The antenna switching operation is completed by the antenna switching unit 3, and the detection operation for detecting the signal strength received by the first antenna 1 and the signal strength received by the second antenna 2 is completed by the receiver 4). At other time marks, the data receiving device executes the corresponding data receiving operation. FIG. 4D shows that one receiving antenna selected by one antenna selection operation is continuously used until the next antenna selection operation starts. That is, the receiving antenna selected by one antenna selection operation completed at the time mark 1 shown in FIG. 4D is continuously used until the next antenna selection operation is started at the next time mark 2.

In addition, it is not necessary to use both the synchronization word SW and the color code CC to perform the synchronization capture operation, but only one synchronization word SW may be used to perform the synchronization capture operation. In this way, in the case of performing synchronization capture using the synchronization word contained in the first time period of each subframe, the data receiving device performs synchronization capture by using the synchronization word SW contained in the first time period of each subframe, and then The antenna selection is performed at the time marks of the synchronization word SW and the color code CC contained in the last two time periods of each subframe. At other time marks, the data receiving device executes the corresponding data receiving operation.

As described above, for the data receiving device of the above-mentioned embodiment of the present invention, when the signal subframe received by the data receiving device is divided into three time periods, for example, intra-step capture is performed in one period of time, and the remaining two The antenna selection operation is performed in each of the period of time. Therefore, it is possible to perform the antenna selection diversity reception operation with only a single receiver system, thereby correspondingly reducing the circuit size, cost, and power consumption of the data receiving device.