CA2162417C - Data rate detector for terminal station receiver - Google Patents
Data rate detector for terminal station receiver Download PDFInfo
- Publication number
- CA2162417C CA2162417C CA 2162417 CA2162417A CA2162417C CA 2162417 C CA2162417 C CA 2162417C CA 2162417 CA2162417 CA 2162417 CA 2162417 A CA2162417 A CA 2162417A CA 2162417 C CA2162417 C CA 2162417C
- Authority
- CA
- Canada
- Prior art keywords
- power
- information
- data rate
- control bit
- power control
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J13/00—Code division multiplex systems
- H04J13/10—Code generation
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0262—Arrangements for detecting the data rate of an incoming signal
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
- H04L1/0036—Systems modifying transmission characteristics according to link quality, e.g. power backoff arrangements specific to the receiver
- H04L1/0039—Systems modifying transmission characteristics according to link quality, e.g. power backoff arrangements specific to the receiver other detection of signalling, e.g. detection of TFCI explicit signalling
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/08—Arrangements for detecting or preventing errors in the information received by repeating transmission, e.g. Verdan system
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B2201/00—Indexing scheme relating to details of transmission systems not covered by a single group of H04B3/00 - H04B13/00
- H04B2201/69—Orthogonal indexing scheme relating to spread spectrum techniques in general
- H04B2201/707—Orthogonal indexing scheme relating to spread spectrum techniques in general relating to direct sequence modulation
- H04B2201/70703—Orthogonal indexing scheme relating to spread spectrum techniques in general relating to direct sequence modulation using multiple or variable rates
- H04B2201/70705—Rate detection
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
- H04L1/0009—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the channel coding
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
- H04L1/0015—Systems modifying transmission characteristics according to link quality, e.g. power backoff characterised by the adaptation strategy
- H04L1/0017—Systems modifying transmission characteristics according to link quality, e.g. power backoff characterised by the adaptation strategy where the mode-switching is based on Quality of Service requirement
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
- H04L1/0023—Systems modifying transmission characteristics according to link quality, e.g. power backoff characterised by the signalling
- H04L1/0025—Transmission of mode-switching indication
Abstract
A data rate detector is used in a terminal station receiver for receiving a coded signal which is transmitted at a selected one of a plurality of information data rates and whose transmission power is controlled to a predetermined ratio in accordance with the selected information data rate. The coded signal has at least one power control bit inserted in one information frame to control the transmission power in a terminal station. The detector includes a bit extractor, a comparator, and a rate determination device. The bit extractor extracts the reception power value of the power control bit and the reception power value of an information symbol other than the power control bit from a plurality of symbols constituting an information frame obtained by demodulating the received coded signal in a predetermined interval. The comparator compares the two reception power values extracted by the bit extractor. The rate determination device detects the information data rate on the basis of the comparison result obtained by the comparator.
Description
DATA RATE DETECTOR FOR TERMINAL STATION RECEIVER
The present invention relates to a data rate detector and, more particularly, to a data rate detector for a terminal station receiver conforming to a code division multiple access scheme defined in TIA~IS (Telecommunication Industry Association International Standard) 95 or the like as a standard of a digital cellular system in North America.
A conventional data rate detector of this type for a terminal station receiver will now be described with reference to Figures 1 and 2.
In the TIA~IS95 scheme, i.e., the CDMA (Code Division Multiple Access) scheme, as a standard of a digital cellular system in North America, when an information signal is to be transmitted from a base station to a terminal station, a data rate selector 21 selects one of four information data rates of 1,200, 2,400, 4,800, and 9,600 bps in a channel for the transmission of information (to be referred to as an information channel hereinafter) from the user, for each information frame time (20 ms), on the basis of the amount, quality, and the like of data such as audio data to be transmitted. The information signal to be transmitted is then output to one of 9,600, 4,800, 2,400, and 1,200 bps encoders 22a to 22d which corresponds to the selected information data rate.
After convolutional coding processing in the encoders 22a to 22d, information frames respectively consisting of 384, 192, 96, and 48 symbols are output from the encoders 22a to 22d. According to TIA~IS95, the information frames based on the respective information data rates and consisting of the different numbers of symbols respectively output from the 4,800, 2,400, and 1,200 bps encoders 22b, 22c, and 22d are repeated in repeating devices 23b to 23d two times, four times, and eight times, respectively, thereby performing repetitive processing of coded frames. That is, the information frames based on the four information data rates are formed such that each frame consists of symbols per information frame time. The information frames are then subjected in modulation 24 to modulation processing such as RF modulation, and the In a conventional terminal station receiver 30 shown in Figure 2, a signal received through a reception antenna 31 is demodulated by a demodulator 32.
In the terminal station receiver 30, when information transmitted from the base station is to be restored on the basis of an output from the demodulator 32, since any specific information data rate on which the information frame is based cannot be determined, decoders 33a to 33d respectively perform decoding processes corresponding to 9,600, 4,800, 2,400, and 1,200 bps for one information channel frame consisting of 384 symbols, which is output from the demodulator 32, in consideration of all the four information data rates. The most probable information data rate is then determined as the information data rate used in the base station in accordance with the decoding results.
More specifically, the decoding results are produced by the decoders 33a to 33d for the four information data rates, i.e., 9,600, 4,800, 2,400, and 1,200 bps, respectively. Re-coders 34a to 34d then perform the same coding processes as those performed in the base station, including repetition processes, for the decoding results, respectively, thereby newly forming information frames, each consisting of 384 symbols. Correlators 35a to 35d perform correlation calculation between the received information frames and the newly formed information frames, respectively. A comparing/determining device 36 obtains one of the four correlation results which has a maximum value. The information data rate corresponding to the correlation result having the maximum value is then determined as the information data rate of the data transmitted from the base station.
A transmitter 20 in Figure 1 further includes a PCB (Power Control Bit) generator 25 for generating a PCB to be inserted in an information channel frame to control the transmission power supplied to the terminal station having the receiver 30. The modulator 24 performs modulation by inserting the PCB from the PCB generator 25 into the information channel frame. Although not shown, the receiver 30 in Figure 2 extracts the PCB from the demodulated information channel frame to control the transmission power.
The present invention relates to a data rate detector and, more particularly, to a data rate detector for a terminal station receiver conforming to a code division multiple access scheme defined in TIA~IS (Telecommunication Industry Association International Standard) 95 or the like as a standard of a digital cellular system in North America.
A conventional data rate detector of this type for a terminal station receiver will now be described with reference to Figures 1 and 2.
In the TIA~IS95 scheme, i.e., the CDMA (Code Division Multiple Access) scheme, as a standard of a digital cellular system in North America, when an information signal is to be transmitted from a base station to a terminal station, a data rate selector 21 selects one of four information data rates of 1,200, 2,400, 4,800, and 9,600 bps in a channel for the transmission of information (to be referred to as an information channel hereinafter) from the user, for each information frame time (20 ms), on the basis of the amount, quality, and the like of data such as audio data to be transmitted. The information signal to be transmitted is then output to one of 9,600, 4,800, 2,400, and 1,200 bps encoders 22a to 22d which corresponds to the selected information data rate.
After convolutional coding processing in the encoders 22a to 22d, information frames respectively consisting of 384, 192, 96, and 48 symbols are output from the encoders 22a to 22d. According to TIA~IS95, the information frames based on the respective information data rates and consisting of the different numbers of symbols respectively output from the 4,800, 2,400, and 1,200 bps encoders 22b, 22c, and 22d are repeated in repeating devices 23b to 23d two times, four times, and eight times, respectively, thereby performing repetitive processing of coded frames. That is, the information frames based on the four information data rates are formed such that each frame consists of symbols per information frame time. The information frames are then subjected in modulation 24 to modulation processing such as RF modulation, and the In a conventional terminal station receiver 30 shown in Figure 2, a signal received through a reception antenna 31 is demodulated by a demodulator 32.
In the terminal station receiver 30, when information transmitted from the base station is to be restored on the basis of an output from the demodulator 32, since any specific information data rate on which the information frame is based cannot be determined, decoders 33a to 33d respectively perform decoding processes corresponding to 9,600, 4,800, 2,400, and 1,200 bps for one information channel frame consisting of 384 symbols, which is output from the demodulator 32, in consideration of all the four information data rates. The most probable information data rate is then determined as the information data rate used in the base station in accordance with the decoding results.
More specifically, the decoding results are produced by the decoders 33a to 33d for the four information data rates, i.e., 9,600, 4,800, 2,400, and 1,200 bps, respectively. Re-coders 34a to 34d then perform the same coding processes as those performed in the base station, including repetition processes, for the decoding results, respectively, thereby newly forming information frames, each consisting of 384 symbols. Correlators 35a to 35d perform correlation calculation between the received information frames and the newly formed information frames, respectively. A comparing/determining device 36 obtains one of the four correlation results which has a maximum value. The information data rate corresponding to the correlation result having the maximum value is then determined as the information data rate of the data transmitted from the base station.
A transmitter 20 in Figure 1 further includes a PCB (Power Control Bit) generator 25 for generating a PCB to be inserted in an information channel frame to control the transmission power supplied to the terminal station having the receiver 30. The modulator 24 performs modulation by inserting the PCB from the PCB generator 25 into the information channel frame. Although not shown, the receiver 30 in Figure 2 extracts the PCB from the demodulated information channel frame to control the transmission power.
In the above conventional data rate determination method, since the information data rate of an information frame obtained from a received signal cannot be determined, decoding processes corresponding to the four information data rates, i.e., 9,600, 4,800, 2,400, and 1,200 bps are performed to cope with all the four information data rates. Re-coding processes are then performed for the four decoding results. Correlation calculation is performed between the resultant frames and the received frames. The information data rate corresponding to the correlation result having the maximum value is selected as the information data rate.
In order to realize such a method, a large number of processing steps are required. In addition, three of the four results corresponding to the information data rates, which are obtained by decoding processes, re-decoding processes, and correlation calculation, are discarded, and hence high efficiency cannot be expected.
It is an object of the present invention to seek to overcome the deficiencies of the prior art by providing a data rate detector which identifies the information data rate used for a received frame before a decoding process to allow reductions in circuit arrangement, processing amount, and the overall power consumption of the receiver.
In order to achieve the above object, according to the present invention, there is provided a data rate detector for a terminal station receiver for receiving a coded signal which is transmitted at a selected one of a plurality of information data rates and whose transmission power is controlled to a predetermined ratio in accordance with the selected information data rate, the coded signal having at least one power control bit inserted in one information frame to control the transmission power in a terminal station, the data rate detector comprising power extraction means for extracting a reception power value of the power control bit and a reception power value of an information symbol other than the power control bit from a plurality of symbols constituting an information frame obtained by demodulating the received coded signal in a predetermined interval, comparing means for comparing the two reception power values extracted by the power extraction means, and detection means for predetermined interval, comparing means for comparing the two reception power values extracted by the power extraction means, and detection means for detecting a used information data rate on the basis of the comparison result obtained by the comparing means.
Embodiments of th.e invention will now be described, by way of example, with reference to the accompanying drawings, in which:
Figure 1 is a block diagram showing a conventional transmitter;
Figure 2 is a block diagram showing a conventional receiver for receiving data from the transmitter shown in Figure 1;
Figure 3 is a block diagram showing a receiver according to an embodiment of the present invention; and Figure 4 is a graph showing the relationship between the PCB, the information symbols at the respective information data rates, and the respective reception power values.
An embodiment of the present invention will be described below with reference to Figures 3 and 4.
Figure 3 shows the schematic arrangement of a receiver 1 for receiving a signal from a transmitter 20 in Figure 1. Referring to Figure 3, a receiver includes a reception antenna 2 for receiving an information channel frame transmitted from the transmitter 20 in Figure 1, a demodulator 3 for demodulating the information channel frame from the reception antenna 2, a frame register 4 for temporarily storing the demodulation result corresponding to one information frame output from the demodulator 3, a bit extractor 5 for extracting a PCB
and an information symbol from the demodulation result stored in the frame register 4, integrators 6a and 6b for respectively integrating the power values of the PCB
and the information symbol extracted by the bit extractor 5, a comparator 7 for comparing the respective integration values obtained by the integrators 6a and 6b, a rate determination device 8 for determining one of the information data rates 1,200, 2,400, 4,800, and 9,600 bps on the basis of the comparison result obtained by the comparator 7, decoders 9a to 9d which are arranged in correspondence with the four information data rates and adapted to perform a decoding process corresponding to the information data rate determined by the the PCB extracted by the bit extractor 5. The transmission power controller 10 has a puncture process 10a for performing puncture processing of the PCB
extracted by the bit extractor 5.
In the receiver 1 having the above arrangement, a signal received 5 through the reception antenna 2 is demodulated by the demodulator 3. The demodulation result is output to the frame register 4. The frame register 4 sequentially stores the demodulation result corresponding to one information frame. The demodulation result includes at least one PCB, which was inserted by the transmitter 20 to control the transmission power, and other information bits. The bit extractor 5 extracts the PCB and an information symbol immediately preceding the PCB.
The PCB extracted by the bit extractor 5 is output to the transmission power controller 10. The transmission power controller 10 estimates a transmission loss (attenuation amount) between the transmitter 20 and the receiver 1 on the basis of the power of the PCB, and predicts the power required for transmission from the estimated transmission loss, thereby controlling the transmission power. The puncture processor 10a performs puncture processing for the PCB portion extracted by the bit extractor 5, i.e., replacing the demodulation result corresponding to the PCB with a neutral erasure symbol to cause the demodulation result to be neglected in an audio decoding operation.
The PCB and the information symbol immediately preceding the PCB, which are extracted by the bit extractor 5, are respectively supplied to the integrators 6a and 6b. The integrators 6a and 6b respectively integrate the power values of the PCB and the information bit. The integration processes in the integrators 6a and 6b reduce the influence of noise added to a signal on the communication line, and also average/reduce the influence of power variations due to multipath fading on the communication line. The integrators 6a and 6b output the power integration results to the comparator 7. The comparator 7 compares the results obtained by integrating the power values of a PCB and an information symbol input for, e.g., each information frame. The comparison result is sent to the rate determination device 8.
In order to realize such a method, a large number of processing steps are required. In addition, three of the four results corresponding to the information data rates, which are obtained by decoding processes, re-decoding processes, and correlation calculation, are discarded, and hence high efficiency cannot be expected.
It is an object of the present invention to seek to overcome the deficiencies of the prior art by providing a data rate detector which identifies the information data rate used for a received frame before a decoding process to allow reductions in circuit arrangement, processing amount, and the overall power consumption of the receiver.
In order to achieve the above object, according to the present invention, there is provided a data rate detector for a terminal station receiver for receiving a coded signal which is transmitted at a selected one of a plurality of information data rates and whose transmission power is controlled to a predetermined ratio in accordance with the selected information data rate, the coded signal having at least one power control bit inserted in one information frame to control the transmission power in a terminal station, the data rate detector comprising power extraction means for extracting a reception power value of the power control bit and a reception power value of an information symbol other than the power control bit from a plurality of symbols constituting an information frame obtained by demodulating the received coded signal in a predetermined interval, comparing means for comparing the two reception power values extracted by the power extraction means, and detection means for predetermined interval, comparing means for comparing the two reception power values extracted by the power extraction means, and detection means for detecting a used information data rate on the basis of the comparison result obtained by the comparing means.
Embodiments of th.e invention will now be described, by way of example, with reference to the accompanying drawings, in which:
Figure 1 is a block diagram showing a conventional transmitter;
Figure 2 is a block diagram showing a conventional receiver for receiving data from the transmitter shown in Figure 1;
Figure 3 is a block diagram showing a receiver according to an embodiment of the present invention; and Figure 4 is a graph showing the relationship between the PCB, the information symbols at the respective information data rates, and the respective reception power values.
An embodiment of the present invention will be described below with reference to Figures 3 and 4.
Figure 3 shows the schematic arrangement of a receiver 1 for receiving a signal from a transmitter 20 in Figure 1. Referring to Figure 3, a receiver includes a reception antenna 2 for receiving an information channel frame transmitted from the transmitter 20 in Figure 1, a demodulator 3 for demodulating the information channel frame from the reception antenna 2, a frame register 4 for temporarily storing the demodulation result corresponding to one information frame output from the demodulator 3, a bit extractor 5 for extracting a PCB
and an information symbol from the demodulation result stored in the frame register 4, integrators 6a and 6b for respectively integrating the power values of the PCB
and the information symbol extracted by the bit extractor 5, a comparator 7 for comparing the respective integration values obtained by the integrators 6a and 6b, a rate determination device 8 for determining one of the information data rates 1,200, 2,400, 4,800, and 9,600 bps on the basis of the comparison result obtained by the comparator 7, decoders 9a to 9d which are arranged in correspondence with the four information data rates and adapted to perform a decoding process corresponding to the information data rate determined by the the PCB extracted by the bit extractor 5. The transmission power controller 10 has a puncture process 10a for performing puncture processing of the PCB
extracted by the bit extractor 5.
In the receiver 1 having the above arrangement, a signal received 5 through the reception antenna 2 is demodulated by the demodulator 3. The demodulation result is output to the frame register 4. The frame register 4 sequentially stores the demodulation result corresponding to one information frame. The demodulation result includes at least one PCB, which was inserted by the transmitter 20 to control the transmission power, and other information bits. The bit extractor 5 extracts the PCB and an information symbol immediately preceding the PCB.
The PCB extracted by the bit extractor 5 is output to the transmission power controller 10. The transmission power controller 10 estimates a transmission loss (attenuation amount) between the transmitter 20 and the receiver 1 on the basis of the power of the PCB, and predicts the power required for transmission from the estimated transmission loss, thereby controlling the transmission power. The puncture processor 10a performs puncture processing for the PCB portion extracted by the bit extractor 5, i.e., replacing the demodulation result corresponding to the PCB with a neutral erasure symbol to cause the demodulation result to be neglected in an audio decoding operation.
The PCB and the information symbol immediately preceding the PCB, which are extracted by the bit extractor 5, are respectively supplied to the integrators 6a and 6b. The integrators 6a and 6b respectively integrate the power values of the PCB and the information bit. The integration processes in the integrators 6a and 6b reduce the influence of noise added to a signal on the communication line, and also average/reduce the influence of power variations due to multipath fading on the communication line. The integrators 6a and 6b output the power integration results to the comparator 7. The comparator 7 compares the results obtained by integrating the power values of a PCB and an information symbol input for, e.g., each information frame. The comparison result is sent to the rate determination device 8.
Information symbols corresponding to the information data rates, i.e., 9,600, 4,800, 2,400, and 1,200 bps, are transmitted from the transmitter 20 at power ratios with respect to the PCB. As shown in Figure 4, at an information data rate of 9,600 bps, the power ratio of the PCB to the information symbol is set to be 1:1; at an information data rate of 4,800 bps, 2:1; at an information data rate of 2,400 bps, 4:1; and, at 1,200 bps, 8:1.
The rate determination device 8 therefore determines an information data rate in such a manner that if R 5 1.5 where R is the ratio of the power of the PCB integrated by the integrator 6a to the power of the information symbol integrated by the integrator 6b, 9,600 bps is selected; if 1.5 < R <_ 3, 4,800 bps is selected; if 3 < R <_ 6, 2,400 bps is selected; and R > 6, 1,200 bps is selected.
The result is used to select one of the decoders 9a to 9d.
As described above, according to this embodiment, the information data rate used for a received frame can be determined before a decoding process without requiring many circuits and many steps in arithmetic processing, which are required for the conventional scheme of performing decoding processes with respect to all the four information data rates, i.e., 9,600 bps, 4,800 bps, 2,400 bps, and 1,200 bps, re-coding the decoded results, and performing correlation processing with respect to the reception system.
The present invention will now be described with reference to the case where an information signal is transmitted from a base station (transmitter 20) to a terminal station (receiver 1 ).
In the terminal station, an information data rate is determined before a decoding process on the basis of a PCB inserted in each information frame in the base station.
As described above with reference to TIA~IS95, in transmitting a signal from the base station to the terminal station, one of the four information data rates, i.e., 1,200, 2,400, 4,800, and 9,600 bps is selected for each information frame time (20 ms) in accordance with the amount and quality of data to be transmitted by the user. The transmission output power is represented by ratios of 1/8, 1/4, 1/2, and 1 in correspondence with the four transmission ratios, respectively, when the output is assumed to be "1" at 9,600 bps. Different power values are used accordingly.
The information data rate used for the information frame can therefore be determined from the reception power in the terminal station.
In the transmitter 20 of the base station, the PCB generator 25 inserts a plurality of PCBs (16 PCBs per information frame in practice) in each information frame at predetermined intervals to control the transmission power (the power required for transmission of a signal from the terminal station to the base station) in the terminal station.
In this case, since the base station transmits each information frame after inserting (overwriting) PCBs on information bits at predetermined positions, the terminal station can recognize which symbols in the information frame are the PCBs. When the terminal station is to restore information transmitted from the base station, the information is decoded after the PCB portions are removed.
A constant transmission power value is set for each PCB. That is, the same value of transmission power is used to transmit an information frame at 9,600 bps for each PCB.
In the terminal station receiver, therefore, the information data rate used in the base station to transmit a given frame can be determined by checking the power value of each information symbol in the received frame with reference to the reception power value of each PCB.
More specifically, when the power ratio of the PCB to the information symbol on the information frame is 1:1, the information data rate of the frame is 9,600 bps; when 1:2, 4,800 bps; when 1:4, 2,400 bps; and when 1:8, 1,200 bps.
On a communication line, noise or the like is added to a signal transmitted from the base station. For this reason, the power values of a plurality of PCBs inserted in one information frame are integrated, and the power values of information symbols equal in number to the PCBs are also integrated. The two obtained results are then compared with each other. With this operation, the influence of the noise added to a signal on the communication line can be reduced (filtering).
In general, a terminal station receiver has an AGC (Automatic Gain Control) circuit. This circuit controls the gain of an amplifier with respect to a received signal such that the power of the received signal is kept constant over time. This control is preferably performed at a speed which allows the control operation to follow power variations due to multipath fading on the communication line. More specifically, the speed is set to be about several hundred Hz.
Although the gain of the amplifier may be changed in one information frame by the AGC circuit, the influence of a change in the gain of the amplifier due to the AGC circuit can be eliminated by comparing the power value of a PCB
with that of an information symbol immediately preceding or succeeding the PCB.
As has been described above, according to the present invention, the information data rate used for a received frame can be determined before a decoding process without requiring many steps in arithmetic processing, which are required for the conventional scheme of performing decoding processes with respect to all the information data rates, re-coding the decoded results, and performing correlation processing with respect to the reception system.
Therefore, substantial reductions in circuit arrangement and in the amount of processing can be realized, and the overall power consumption of the terminal station receiver can also be reduced.
According to the present invention, the circuit size of the terminal station receiver conforming to the TIA~IS95 scheme (CDMA) as a standard of a digital cellular system in North America is reduced, and reductions in power consumption and cost are attained.
In addition, according to the present invention, by integrating outputs from the bit extraction means, the influence of noise added to a signal on a communication line can be reduced, and the influence of power variations due to multipath fading on the communication line is averaged and reduced, thereby improving the data rate detection precision.
Furthermore, according to the present invention, the influence of a change in the gain of an amplifier due to the AGC circuit can be eliminated by comparing the power value of a PCB with that of an information symbol immediately preceding or succeeding the PCB.
The rate determination device 8 therefore determines an information data rate in such a manner that if R 5 1.5 where R is the ratio of the power of the PCB integrated by the integrator 6a to the power of the information symbol integrated by the integrator 6b, 9,600 bps is selected; if 1.5 < R <_ 3, 4,800 bps is selected; if 3 < R <_ 6, 2,400 bps is selected; and R > 6, 1,200 bps is selected.
The result is used to select one of the decoders 9a to 9d.
As described above, according to this embodiment, the information data rate used for a received frame can be determined before a decoding process without requiring many circuits and many steps in arithmetic processing, which are required for the conventional scheme of performing decoding processes with respect to all the four information data rates, i.e., 9,600 bps, 4,800 bps, 2,400 bps, and 1,200 bps, re-coding the decoded results, and performing correlation processing with respect to the reception system.
The present invention will now be described with reference to the case where an information signal is transmitted from a base station (transmitter 20) to a terminal station (receiver 1 ).
In the terminal station, an information data rate is determined before a decoding process on the basis of a PCB inserted in each information frame in the base station.
As described above with reference to TIA~IS95, in transmitting a signal from the base station to the terminal station, one of the four information data rates, i.e., 1,200, 2,400, 4,800, and 9,600 bps is selected for each information frame time (20 ms) in accordance with the amount and quality of data to be transmitted by the user. The transmission output power is represented by ratios of 1/8, 1/4, 1/2, and 1 in correspondence with the four transmission ratios, respectively, when the output is assumed to be "1" at 9,600 bps. Different power values are used accordingly.
The information data rate used for the information frame can therefore be determined from the reception power in the terminal station.
In the transmitter 20 of the base station, the PCB generator 25 inserts a plurality of PCBs (16 PCBs per information frame in practice) in each information frame at predetermined intervals to control the transmission power (the power required for transmission of a signal from the terminal station to the base station) in the terminal station.
In this case, since the base station transmits each information frame after inserting (overwriting) PCBs on information bits at predetermined positions, the terminal station can recognize which symbols in the information frame are the PCBs. When the terminal station is to restore information transmitted from the base station, the information is decoded after the PCB portions are removed.
A constant transmission power value is set for each PCB. That is, the same value of transmission power is used to transmit an information frame at 9,600 bps for each PCB.
In the terminal station receiver, therefore, the information data rate used in the base station to transmit a given frame can be determined by checking the power value of each information symbol in the received frame with reference to the reception power value of each PCB.
More specifically, when the power ratio of the PCB to the information symbol on the information frame is 1:1, the information data rate of the frame is 9,600 bps; when 1:2, 4,800 bps; when 1:4, 2,400 bps; and when 1:8, 1,200 bps.
On a communication line, noise or the like is added to a signal transmitted from the base station. For this reason, the power values of a plurality of PCBs inserted in one information frame are integrated, and the power values of information symbols equal in number to the PCBs are also integrated. The two obtained results are then compared with each other. With this operation, the influence of the noise added to a signal on the communication line can be reduced (filtering).
In general, a terminal station receiver has an AGC (Automatic Gain Control) circuit. This circuit controls the gain of an amplifier with respect to a received signal such that the power of the received signal is kept constant over time. This control is preferably performed at a speed which allows the control operation to follow power variations due to multipath fading on the communication line. More specifically, the speed is set to be about several hundred Hz.
Although the gain of the amplifier may be changed in one information frame by the AGC circuit, the influence of a change in the gain of the amplifier due to the AGC circuit can be eliminated by comparing the power value of a PCB
with that of an information symbol immediately preceding or succeeding the PCB.
As has been described above, according to the present invention, the information data rate used for a received frame can be determined before a decoding process without requiring many steps in arithmetic processing, which are required for the conventional scheme of performing decoding processes with respect to all the information data rates, re-coding the decoded results, and performing correlation processing with respect to the reception system.
Therefore, substantial reductions in circuit arrangement and in the amount of processing can be realized, and the overall power consumption of the terminal station receiver can also be reduced.
According to the present invention, the circuit size of the terminal station receiver conforming to the TIA~IS95 scheme (CDMA) as a standard of a digital cellular system in North America is reduced, and reductions in power consumption and cost are attained.
In addition, according to the present invention, by integrating outputs from the bit extraction means, the influence of noise added to a signal on a communication line can be reduced, and the influence of power variations due to multipath fading on the communication line is averaged and reduced, thereby improving the data rate detection precision.
Furthermore, according to the present invention, the influence of a change in the gain of an amplifier due to the AGC circuit can be eliminated by comparing the power value of a PCB with that of an information symbol immediately preceding or succeeding the PCB.
Claims (11)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A data rate detector for a terminal station receiver for receiving a coded signal which is transmitted at a selected one of a plurality of information data rates and whose transmission power is controlled to a predetermined ratio in accordance with the selected information data rate, the coded signal having at least one power control bit inserted in one information frame to control the transmission power in a terminal station, said data rate detector comprising:
power extraction means for extracting a reception power value of the power control bit and a reception power value of an information symbol other than the power control bit from a plurality of symbols constituting an information frame obtained by demodulating the received coded signal in a predetermined interval;
comparing means for comparing the two reception power values extracted by said power extraction means; and detection means for detecting an information data rate on the basis of the comparison result obtained by said comparing means.
power extraction means for extracting a reception power value of the power control bit and a reception power value of an information symbol other than the power control bit from a plurality of symbols constituting an information frame obtained by demodulating the received coded signal in a predetermined interval;
comparing means for comparing the two reception power values extracted by said power extraction means; and detection means for detecting an information data rate on the basis of the comparison result obtained by said comparing means.
2. A detector according to claim 1, wherein the power control bit includes a plurality of power control bits inserted in one information frame at predetermined positions.
3. A detector according to claim 1, further comprising first and second integration means for respectively integrating, the same number of times, the two reception power values extracted by said power extraction means and wherein said comparing means compares integration results from said first and second integration means for each information frame.
4. A detector according to claim 1, wherein said power extraction means extracts a reception power value of an information symbol at a position immediately before the power control bit.
5. A detector according to claim 1, further comprising a plurality of decoding means, arranged in correspondence with the information data rates, for decoding a demodulated information frame, and wherein said detection means selects one of said decoding means in accordance with a detected information data rate.
6. A detector according to claim 1, further comprising demodulation means for demodulating a received signal, and register means for storing one information frame output from said demodulation means, and wherein said power extraction means extracts reception power values of the power control bit and the information symbol from one information frame stored in said register means.
7. A detector according to claim 1, further comprising transmission power control means for controlling the transmission power in the terminal station on the basis of the reception power value of the power control bit which is extracted by said power extraction means, and puncture processing means for performing puncture processing of the power control bit inserted in the information frame.
8. A detector according to claim 1, wherein the coded signal is transmitted in accordance with a code division multiple access scheme.
9. A data rate detector for a terminal station receiver for receiving a coded signal which is transmitted at a selected one of a plurality of information data rates and whose transmission power is controlled to a predetermined ratio in accordance with the selected information data rate, the coded signal having at least one power control bit inserted in one information frame to control the transmission power in a terminal station, said data rate detector comprising:
power extraction means for extracting a reception power value of the power control bit and a reception power value of an information symbol other than the power control bit from a plurality of symbols constituting an information frame obtained by demodulating the received coded signal in a predetermined interval;
first and second integration means for respectively integrating, the same number of times, the two reception power values extracted by said power extraction means;
comparing means for comparing the integration results from said first and second integration means with each other; and detection means for detecting an information data rate on the basis of the comparison result obtained by said comparing means.
power extraction means for extracting a reception power value of the power control bit and a reception power value of an information symbol other than the power control bit from a plurality of symbols constituting an information frame obtained by demodulating the received coded signal in a predetermined interval;
first and second integration means for respectively integrating, the same number of times, the two reception power values extracted by said power extraction means;
comparing means for comparing the integration results from said first and second integration means with each other; and detection means for detecting an information data rate on the basis of the comparison result obtained by said comparing means.
10. A terminal station receiver for receiving a coded signal which is transmitted at a selected one of a plurality of information data rates and whose transmission power is controlled to a predetermined ratio in accordance with the selected information data rate, the coded signal having at least one power control bit inserted in one information frame to control the transmission power in a terminal station, said terminal station receiver comprising:
demodulation means for demodulating the received coded signal;
register means for storing one information frame output from said demodulation means;
power extraction means for extracting a reception power value of the power control bit and a reception power value of an information symbol immediately preceding the power control bit from a plurality of symbols constituting the one information frame stored in said register means;
first and second integration means for respectively integrating, the same number of times, the two reception power values extracted by said power extraction means;
comparing means for comparing the integration results from said first and second integration means with each other;
detection means for detecting an information data rate on the basis of the comparison result obtained by said comparing means; and a plurality of decoding means, arranged in correspondence with the information data rates, for decoding a demodulated information frame, said decoding means being selected by said detection means.
demodulation means for demodulating the received coded signal;
register means for storing one information frame output from said demodulation means;
power extraction means for extracting a reception power value of the power control bit and a reception power value of an information symbol immediately preceding the power control bit from a plurality of symbols constituting the one information frame stored in said register means;
first and second integration means for respectively integrating, the same number of times, the two reception power values extracted by said power extraction means;
comparing means for comparing the integration results from said first and second integration means with each other;
detection means for detecting an information data rate on the basis of the comparison result obtained by said comparing means; and a plurality of decoding means, arranged in correspondence with the information data rates, for decoding a demodulated information frame, said decoding means being selected by said detection means.
11. A receiver according to claim 10, further comprising transmission power control means for controlling the transmission power in the terminal station on the basis of the reception power value of the power control bit which is extracted by said power extraction means, and puncture processing means for performing puncture processing of the power control bit inserted in the information frame.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30573494A JP2596392B2 (en) | 1994-11-16 | 1994-11-16 | Data rate detector |
| JP305734/94 | 1994-11-16 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2162417A1 CA2162417A1 (en) | 1996-05-17 |
| CA2162417C true CA2162417C (en) | 2000-01-11 |
Family
ID=17948710
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2162417 Expired - Fee Related CA2162417C (en) | 1994-11-16 | 1995-11-08 | Data rate detector for terminal station receiver |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US5771226A (en) |
| EP (1) | EP0713305B1 (en) |
| JP (1) | JP2596392B2 (en) |
| KR (1) | KR0176993B1 (en) |
| AU (1) | AU686026B2 (en) |
| CA (1) | CA2162417C (en) |
| DE (1) | DE69530554T2 (en) |
| FI (1) | FI955398A (en) |
Families Citing this family (48)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ZA965340B (en) | 1995-06-30 | 1997-01-27 | Interdigital Tech Corp | Code division multiple access (cdma) communication system |
| KR970013834A (en) * | 1995-08-23 | 1997-03-29 | 사와무라 시코우 | A computing apparatus of transmission rate |
| US5883923A (en) * | 1995-09-18 | 1999-03-16 | Oki Electric Industry Co., Ltd. | Data receiver with symbol rate discrimination and statistical analysis functions |
| FI956358A (en) * | 1995-12-29 | 1997-06-30 | Nokia Telecommunications Oy | Method for detecting data transfer rate and receiver |
| US5872775A (en) * | 1996-10-30 | 1999-02-16 | Qualcomm Incorporated | Method and apparatus for performing rate determination |
| US6108372A (en) * | 1996-10-30 | 2000-08-22 | Qualcomm Inc. | Method and apparatus for decoding variable rate data using hypothesis testing to determine data rate |
| FI106666B (en) | 1997-01-24 | 2001-03-15 | Nokia Networks Oy | Power control method for discontinuous transmission |
| US5907582A (en) * | 1997-08-11 | 1999-05-25 | Orbital Sciences Corporation | System for turbo-coded satellite digital audio broadcasting |
| US9118387B2 (en) | 1997-11-03 | 2015-08-25 | Qualcomm Incorporated | Pilot reference transmission for a wireless communication system |
| US7184426B2 (en) * | 2002-12-12 | 2007-02-27 | Qualcomm, Incorporated | Method and apparatus for burst pilot for a time division multiplex system |
| JPH11163961A (en) * | 1997-11-26 | 1999-06-18 | Matsushita Electric Ind Co Ltd | Method for judging transmission rate and its device |
| US6112325A (en) | 1998-01-23 | 2000-08-29 | Dspc Technologies, Ltd. | Method and device for detecting rate |
| US6134278A (en) * | 1998-01-30 | 2000-10-17 | Lucent Technologies Inc. | Methods and apparatus for CDMA rate detection |
| US6424631B1 (en) * | 1998-06-11 | 2002-07-23 | Infineon Technologies North America Corp. | Apparatus and methods for determining rate of transmitted variable rate data |
| JP3484980B2 (en) * | 1998-06-23 | 2004-01-06 | 日本電気株式会社 | Wireless receiver |
| GB9814757D0 (en) * | 1998-07-07 | 1998-09-02 | Ubayasiri Sudathshu | Data link |
| US6347080B2 (en) * | 1998-09-09 | 2002-02-12 | Qualcomm, Inc. | Energy based communication rate detection system and method |
| US6687233B1 (en) * | 1998-10-16 | 2004-02-03 | Koninklijke Philips Electronics N.V. | Rate detection in direct sequence code division multiple access systems |
| US6427165B1 (en) | 1998-11-18 | 2002-07-30 | Gateway, Inc. | Method and apparatus for information retrieval from a network using parameter value sampling |
| US6463031B1 (en) * | 1998-12-03 | 2002-10-08 | Nokia Mobile Phones Limited | Rate determination technique that utilizes modified cumulative metrics to orthogonalize the rates |
| JP2000196467A (en) * | 1998-12-28 | 2000-07-14 | Nec Corp | Error correction coder and error correction decoder |
| US6377618B1 (en) * | 1998-12-30 | 2002-04-23 | Agere Systems Guardian Corp. | Auto-correlation system and method for rate detection of a data communication channel |
| US6567466B1 (en) * | 1999-02-16 | 2003-05-20 | Agere Systems Inc. | Method and apparatus for determining the data rate of a received signal in a variable data rate orthogonal spread spectrum communication system |
| US6477522B1 (en) | 1999-06-10 | 2002-11-05 | Gateway, Inc. | Dynamic performance based server selection |
| EP1114530B1 (en) | 1999-07-08 | 2005-02-02 | Samsung Electronics Co., Ltd. | Data rate detection device and method for a mobile communication system |
| US8064409B1 (en) | 1999-08-25 | 2011-11-22 | Qualcomm Incorporated | Method and apparatus using a multi-carrier forward link in a wireless communication system |
| US6591314B1 (en) | 1999-08-30 | 2003-07-08 | Gateway, Inc. | Video input selection for information handling system |
| US6621804B1 (en) * | 1999-10-07 | 2003-09-16 | Qualcomm Incorporated | Method and apparatus for predicting favored supplemental channel transmission slots using transmission power measurements of a fundamental channel |
| JP2001186082A (en) * | 1999-12-24 | 2001-07-06 | Matsushita Electric Ind Co Ltd | Cdma mobile communication system and method |
| EP1305884A2 (en) * | 2000-08-04 | 2003-05-02 | TELEFONAKTIEBOLAGET LM ERICSSON (publ) | Spreading factor detector |
| DE60110168T2 (en) * | 2000-08-23 | 2006-02-09 | Siemens Vdo Automotive Corporation, Auburn Hills | Remote control receiver with at least two modulation methods |
| KR100703432B1 (en) * | 2000-09-06 | 2007-04-03 | 삼성전자주식회사 | Method for detecting data rate in wireless communication system |
| US6973098B1 (en) | 2000-10-25 | 2005-12-06 | Qualcomm, Incorporated | Method and apparatus for determining a data rate in a high rate packet data wireless communications system |
| US7068683B1 (en) | 2000-10-25 | 2006-06-27 | Qualcomm, Incorporated | Method and apparatus for high rate packet data and low delay data transmissions |
| US6810078B2 (en) * | 2000-12-08 | 2004-10-26 | Prairiecomm, Inc. | Blind rate determination |
| US6975868B2 (en) * | 2001-02-21 | 2005-12-13 | Qualcomm Incorporated | Method and apparatus for IS-95B reverse link supplemental code channel frame validation and fundamental code channel rate decision improvement |
| KR100396778B1 (en) * | 2001-06-25 | 2003-09-02 | 엘지전자 주식회사 | Power controlling method for mobile communication device |
| JP3583388B2 (en) * | 2001-06-29 | 2004-11-04 | 松下電器産業株式会社 | Data communication device and data communication method |
| JP3852401B2 (en) | 2002-12-18 | 2006-11-29 | ソニー・エリクソン・モバイルコミュニケーションズ株式会社 | Signal processing apparatus and method |
| US7299402B2 (en) * | 2003-02-14 | 2007-11-20 | Telefonaktiebolaget Lm Ericsson (Publ) | Power control for reverse packet data channel in CDMA systems |
| US8254358B2 (en) | 2003-03-06 | 2012-08-28 | Ericsson Ab | Communicating a broadcast message to change data rates of mobile stations |
| US7145862B2 (en) * | 2003-04-08 | 2006-12-05 | Motorola, Inc. | Method and apparatus for transmission and reception of data |
| JP2004248315A (en) * | 2004-03-31 | 2004-09-02 | Hitachi Ltd | Dynamic code assignment and code division multiple access communication method, base station and radio terminal for realizing the same |
| US20060176966A1 (en) * | 2005-02-07 | 2006-08-10 | Stewart Kenneth A | Variable cyclic prefix in mixed-mode wireless communication systems |
| US20060245384A1 (en) * | 2005-05-02 | 2006-11-02 | Talukdar Anup K | Method and apparatus for transmitting data |
| US8400998B2 (en) | 2006-08-23 | 2013-03-19 | Motorola Mobility Llc | Downlink control channel signaling in wireless communication systems |
| US8811200B2 (en) | 2009-09-22 | 2014-08-19 | Qualcomm Incorporated | Physical layer metrics to support adaptive station-dependent channel state information feedback rate in multi-user communication systems |
| US9445173B2 (en) * | 2014-03-10 | 2016-09-13 | Infineon Technologies Ag | System and method for a transducer system with wakeup detection |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS594250A (en) * | 1982-06-29 | 1984-01-11 | Fujitsu Ltd | Multi-stage speed control modem |
| US4887280A (en) * | 1986-12-29 | 1989-12-12 | Hughes Aircraft Company | System for detecting the presence of a signal of a particular data rate |
| US5367533A (en) * | 1990-12-05 | 1994-11-22 | Interdigital Technology Corporation | Dynamic capacity allocation CDMA spread spectrum communications |
| JPH0594250A (en) * | 1991-10-02 | 1993-04-16 | Nec Off Syst Ltd | Keyboard |
| EP0565507A3 (en) * | 1992-04-10 | 1994-11-30 | Ericsson Ge Mobile Communicat | Power control for random access call set-up in a mobile telephone system |
| US5511096A (en) * | 1994-01-18 | 1996-04-23 | Gi Corporation | Quadrature amplitude modulated data for standard bandwidth television channel |
| US5619524A (en) * | 1994-10-04 | 1997-04-08 | Motorola, Inc. | Method and apparatus for coherent communication reception in a spread-spectrum communication system |
-
1994
- 1994-11-16 JP JP30573494A patent/JP2596392B2/en not_active Expired - Fee Related
-
1995
- 1995-11-08 CA CA 2162417 patent/CA2162417C/en not_active Expired - Fee Related
- 1995-11-09 FI FI955398A patent/FI955398A/en unknown
- 1995-11-14 US US08/557,610 patent/US5771226A/en not_active Expired - Fee Related
- 1995-11-15 AU AU37875/95A patent/AU686026B2/en not_active Ceased
- 1995-11-15 EP EP19950308175 patent/EP0713305B1/en not_active Expired - Lifetime
- 1995-11-15 DE DE1995630554 patent/DE69530554T2/en not_active Expired - Fee Related
- 1995-11-16 KR KR1019950041584A patent/KR0176993B1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| CA2162417A1 (en) | 1996-05-17 |
| FI955398A0 (en) | 1995-11-09 |
| KR0176993B1 (en) | 1999-05-15 |
| EP0713305B1 (en) | 2003-05-02 |
| FI955398A (en) | 1996-05-17 |
| JP2596392B2 (en) | 1997-04-02 |
| KR960020132A (en) | 1996-06-17 |
| AU3787595A (en) | 1996-05-23 |
| DE69530554D1 (en) | 2003-06-05 |
| JPH08149567A (en) | 1996-06-07 |
| US5771226A (en) | 1998-06-23 |
| EP0713305A1 (en) | 1996-05-22 |
| AU686026B2 (en) | 1998-01-29 |
| DE69530554T2 (en) | 2004-02-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2162417C (en) | Data rate detector for terminal station receiver | |
| JP3866712B2 (en) | Burst detector | |
| JP2701761B2 (en) | Transmission bit rate determination method and apparatus | |
| EP1135884A1 (en) | Noise characterization in a wireless communication system | |
| MXPA02006991A (en) | Efficient system and method for facilitating quick paging channel demodulation via an efficient offline searcher in a wireless communications system. | |
| US7653865B2 (en) | Decoding method and device | |
| JP3311252B2 (en) | Transmission rate estimating apparatus and variable transmission rate communication system using the same | |
| WO1997005717A1 (en) | Apparatus and method for rate determination in on-off variable-rate communication systems | |
| US6275711B1 (en) | Method and apparatus for selecting a base station in CDMA diversity handover | |
| US6898237B2 (en) | Method of, and receiver for, estimating the bit rate of data | |
| US20060227749A1 (en) | Channel estimation for a cdma system using pilot symbols | |
| US6944210B1 (en) | Method for receiving or sending messages | |
| KR100396778B1 (en) | Power controlling method for mobile communication device | |
| JP2743881B2 (en) | Transmission bit rate determination method and apparatus | |
| US8270339B2 (en) | Mobile communication system, mobile communication terminal, and mobile communication method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed | ||
| MKLA | Lapsed |
Effective date: 20021108 |