Title of Invention

'A NON-ORTHOGONAL NOISE DETECTING DEVICE AND METHOD FOR CDMA COMMUNICATION SYSTEM"

Abstract A non-orthogonal noise detecting device for a CDMA communication system. In the device, a despreader 311, despreads multiple channel signals including a specific channel with an orthogonal code assigned to the specific channel repeating at least two same second symbols at a given first symbol duration, to generate despread repeated symbols. A difference signal generator 317 receives the despread second symbols, and generates a difference signal between a presently received second symbol and a previously received second symbol. A noise detector 323 converts the difference signal to an energy value to generate a non-orthogonal noise signal.
Full Text "A NON-ORTHOGONAL NOISE DETECTING DEVICE AND METHOD FOR CDMA COMMUNICATION SYSTEMS"
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to non-orthogonal noise detecting device and method for CDMA communication systems, and in particular, to a device and method for measuring non-orthogonal noise power of a received channel signal.
2. Description of the Related Art
Code division multiple access (CDMA) communication systems use orthogonal
codes for separating channels. In particular, a forward link typically employs a
synchronous CDMA technique which separates users with the orthogonal codes.
In this case, in a non-multi-path environment, there is no interference among the
channels using different orthogonal codes. Also, even in the multi-path
environment, an orthogonally among the respective channels is maintain with
respect to the signal components. Therefore, although some of the signals
inputted
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to the respective fingers act as interference, most of the signals do not act as inference. Such a phenomenon affects a performance of the CDMA communication
system.
Accordingly, for implementation of an effective CDMA communication system, it is necessary to accurately measure the signal components acting as interference, i.e., non-orthogonal noise power. The measured non-orthogonal noise power can be used in measuring a signal-to-interference ratio (SIR) or controlling gains of the fingers in a receiving device.
A method for measuring the non-orthogonal noise power is disclosed in U.S. Patent No. 5,559,790 issued to Yano et al. In the disclosed non-orthogonal noise measuring method, a specified one orthogonal code out of the orthogonal codes for the forward link is not assigned to the forward link, and a base station sends information about the non-assigned orthogonal code to mobile stations. The mobile stations then despread the received channel signal on the forward link with the assigned orthogonal codes, and calculate energy component of the despread channel signal to detect non-orthogonal noise component.
However, in this configuration, since a specific orthogonal code should be assigned to the forward link for measurement of the non-orthogonal noise power, the specific orthogonal code cannot be used for the other channels. That is, even when many orthogonal codes are required to increase efficiency of the forward link, the specific orthogonal code cannot be used. Furthermore, in the IS-95 standard whose standardization has been completed already, it is impossible to use the specific code in measuring the non-orthogonal noise power.
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In addition, U.S. Patent No. 5,754,533 issued to Bender et al. discloses another non-orthogonal noise measuring method wherein a receiving device estimates the energy detected by despreading a received signal on a channel having a low signal power as a non-orthogonal noise component (or power). Here, the channel having the low signal power is an IS-95 sync channel. However, this non-orthogonal noise measuring method estimates a value obtained by adding a signal component, no matter how low it is, to the non-orthogonal noise power. So, it is impossible to measure accurate non-orthogonal noise power.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide a device and method for measuring, at a receiving device, a non-orthogonal noise component included in a signal transmitted from a transmitting device in a CDMA communication system.
It is another object of the present invention to provide a device and method for measuring a non-orthogonal noise component from a repetition pattern for a channel where the same data is repeated, in a CDMA communication system.
It is further another object of the present invention to provide a device and method for measuring a non-orthogonal noise component from a repetition pattern for a traffic channel of low rate, in a CDMA communication system.
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To achieve the above objects, there is provided a non-orthogonal noise detecting device for a CDMA communication system. The device comprises a despreader for dispreading multiple channel signals including a specific channel with an orthogonal code assigned to the specific channel repeating at least two same second symbols at a given first symbol duration, to generate despread repeated symbols; a difference signal generator for receiving the despread second symbols, and generating a difference signal between a presently received second symbol and a previously received signal second symbol; and a noise detector for converting the difference signal to an energy value to generate a non-orthogonal noise signal.
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BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which:
FIG. 1 is a diagram illustrating a channel transmission device for measuring a non-orthogonal noise component in a CDMA communication system according to an embodiment of the present invention;
FIG. 2 is a diagram illustrating a symbol structure for a channel used in measuring non-orthogonal noise power in a channel transmission device of FIG. 1;
FIG. 3 is a diagram illustrating a channel reception device for measuring non-orthogonal noise power in a CDMA communication system according to an embodiment of the present invention;
FIGs. 4A and 4B are diagrams illustrating channel transmission and reception devices for measuring non-orthogonal noise power in a CDMA communication system according to another embodiment of the present invention;
FIG. 5 is a diagram illustrating a mobile station reception device for determining a power control command depending on the non-orthogonal noise power according to an embodiment of the present invention;
FIG. 6 is a diagram illustrating a finger of FIG. 5 according to a first embodiment of the present invention;
FIG. 7 is a diagram illustrating a symbol combiner and SIR measurer of FIG. 5 when the fingers have the structure of FIG. 6;
FIG. 8 is a diagram illustrating a finger of FIG. 5 according to a second embodiment of the present invention; and
FIG. 9 is a diagram illustrating a symbol combiner and SIR measurer of FIG. 5 when the fingers have the structure of FIG. 8.
FIG.10 shows a receiver for measuring non-orthogonal noise power accord-ing to another embodiment of the present invention.
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention is directed to measuring non-orthogonal noise power acting as interference noise to respective fingers in a CDMA communication system. In the embodiment, it is assumed that a forward link channel reception device for receiving a signal outputted from a forward link channel transmission device measures non-orthogonal noise included in the received signal.
In the forward link, since the respective channels are spread with orthogonal codes, some of the signals may function as Interference. Here, the Interference signal is representative of a non-orthogonal component, and an accurate measurement of the non-orthogonal noise component is very important in designing a receiver. Accordingly, to measure a non-orthogonal noise component, the embodiment uses a forward link channel where the same data not including specific information are transmitted or a low rate traffic channel where the same data is repeated. The forward link channel repeating the same data with no specific information may be a pilot channel, and the low rate channel repeating the same data may be a sync channel. Accordingly, a non-orthogonal noise measuring method according to the present invention can assign all the orthogonal codes for the system as orthogonal codes for actually separating the channels. That is, in accordance with the present method, there is no need to dedicate one or more orthogonal codes for the purpose of measuring a non-orthogonal noise component as is performed in the prior art.
With reference to FIG. 1 there is illustrated a channel transmission device for a forward link, which includes a pilot channel not including specific information in an IS-95 system, a low rate sync channel repeating the same symbols, and a traffic channel.

In FIG. 1, a signal on the pilot channel is a signal (composed of all "0"s)not including specific information. A spreader 102 multiplies the pilot signal by an orthogonal code for the pilot channel to generate an orthogonally spread pilot signal. The sync channel includes sync information, but outputs data at a low rate o f 1.2Kbps. The 1,2Kbps signal on the sync channel is encoded by an encoder 104. A convolutional encoder having a coding rate R=l/2 can be used for the encoder 104. In this case, the 1.2Kbps sync channel signal is encoded into 2.4Ksps (symbols per second). A symbol repeater 106 repeats twice the symbols on the sync channel outputted from the encoder 104. An interleaver 108 interleaves the symbols on the sync channel outputted from the symbol repeater 106 to prevent a burst error. A block interleaver can be used for the interleaver 108. A spreader 110 multiplies the sync channel signal outputted from the interleaver 108 by an orthogonal code assigned for the sync channel to generate an orthogonally spread sync channel signal.
The forward link includes traffic channels which establish an exclusive link between a base station and a specific mobile station for transmission of data and voice, and a paging channel which is a common channel used when a base station pages a specific mobile station prior to a call setup. Here, the channel for actually transmitting data is called a traffic channel. In the embodiment, it is assumed that the traffic channel is a paging channel. The traffic channel has a data rate of 19.2Ksps or 9.6Ksps.
The paging channel is a channel for actually transmitting data to a mobile station, and outputs data at a higher rate than the sync channel. The 9.6Kbps (or 4.8Kbps) signal on the paging channel is encoded by an encoder 114, for which an
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R=l/2 convolutional code can be used. In this case, the 9.6Kbps (or 4.8Kbps) paging channel signal is encoded into 19.2Ksps (or 9.6Ksps) symbols. A symbol repeater 116 repeats one time (or two times) the symbols on the paging channel outputted from the encoder 114. An interleaver 118 interleaves the symbols on the paging channel outputted from the symbol repeater 116 to prevent a burst error. A block interleaver can be used for the interleaver 118. A spreader 120 multiplies the paging channel signal outputted from the interleaver 118 by an orthogonal code assigned for the paging channel to generate an orthogonally spread paging channel signal.
It is noted from the foregoing that a final symbol rate of the sync channel is 4.8Ksps, which is 1/4 times a symbol rate (19.2Ksps) of the traffic channel. Accordingly, to match the data rate, 4 symbols of a short period are repeated. Herein, a method for effectively measuring the non-orthogonal noise component will be described with reference to the sync channel, which repeats the same symbols.
The forward link reception device then measures the non-orthogonal noise component using the channels which repeat the same symbols.
With reference to FIG. 2, there is shown a sync channel for the IS-95 forward link, which is despread with an orthogonal code. In FIG. 2, despread symbols S(n -1) ..., S(n-4) constitutes one sync channel symbol unit, which corresponds to 4 short-period symbols. In the sync channel signal, all of the 4 symbols maintain the same value, and the first two symbol values subtracted by the next two symbol values will become zero. However, in the case where the symbols on the sync
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channel include interference signals, the interference component can be detected by calculating a difference between the first two symbols and the following two symbols.
Accordingly, from the received signal on the sync channel, a non-orthogonal noise component can be calculated by

where In and Qn represent symbol values for I-channel and Q-channel of the received complex signal, respectively.
With reference to FIG. 3, there is illustrated a receiver for measuring a non-orthogonal noise component using Equation 1.
Referring to FIG. 3, a despreader 311 multiplies a received signal by an orthogonal code assigned to a specific channel, to despread an orthogonally spread signal. The specific channel can be a channel not carrying specific information or a low rate channel repeating the same data. In the embodiment, the specific channel is assumed to be a sync channel. In this case, the despreader 311 despreads a received spread sync channel signal by multiplying the received signal by an orthogonal code assigned to the sync channel. An accumulator 313 accumulates the sync channel signals outputted from the despreader 311 at periods of one symbol. A delay 315 delays an output signal of the accumulator 313 by one symbol period. A subtracter 317 subtracts a present sync channel symbol value outputted from the
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accumulator 313 from a previous sync channel symbol value outputted from the delay 315, to calculate a difference between the two symbols. A squarer 319 squares the difference value between the two symbols, outputted from the subtracter 317, to detect power of the noise component. A down-sampler 321 down-samples the noise component between specific symbols, outputted from the squarer 319. Also, the down-sampler 321 selects non-orthogonal noise power between the specific symbols from the output of the squarer 319. A filter 323 bandpass filters the non-orthogonal noise power outputted from the down-sampler 321. The filter 323 can be composed of an JIR (Infinite Impulse Response) or FIR (Finite Impulse Response) filters to attain an appropriate bandwidth.
In operation, the received signal being a PN (Pseudo-random Noise) despread baseband signal is multiplied by an orthogonal code for the sync channel to be despread and converted to a symbol unit signal at the despreader 311 and the accumulator 313. The converted symbol-unit signals are provided to the delay 315 and the subtracter 317. The subtracter 317 then calculates the difference between the present symbol and the previous symbol delayed by the delay 315. The output value of the subtracter 317 becomes the non-orthogonal noise component, which is provided to the squarer 319 to calculate the non-orthogonal noise power. The squarer 319 squares the subtracted values for the I- and Q-channels to generate the non-orthogonal noise power. The down-sampler 321 has the function of detecting an output of the squarer 319 in the unit of two symbols. The output of the down-sampler 321 is provided to the filter 323, which controls a bandwidth of the non-orthogonal noise component. The filter 323 bandpass filters the non-orthogonal noise component to output the non-orthogonal noise value at specified periods.
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Although a description has been made regarding the case where the low rate channel used in measuring the non-orthogonal noise component repeats the same data, the same measuring method can be applied even to the case where a transmitter transmits a specific pattern without repeating the same data. This is illustrated in FIGs. 4A and 4B.
First, a description will be made regarding an operation of a transmitter with reference to FIG. 4A. A channel 401 to be transmitted is a channel having a low rate data of 1.2Kbps. A 1.2Kbps signal on the low rate channel is encoded by an encoder 402, for which an R=l/2 convolutional encoder can be used. In this case, the low rate signal of 1.2Kbps is encoded into 2.4Ksps symbols. A symbol repeater 403 repeats two times the low rate channel symbols outputted from the encoder 402 to output 4.8K symbols per second. An interleaver 404 interleaves the low rate channel symbols outputted from the symbol repeater 403 to prevent a burst error. A block i nterleaver can be used for the interleaver 404. A multiplier 406 multiplies an output of the interleaver 404 by an output of a pattern generator 405. Here, the pattern generator 405 and the multiplier 406 constitute an inserter. A despreader 408 multiplies a low rate channel signal outputted from the multiplier 406 by an orthogonal code assigned to the low rate channel to generate an orthogonally spread signal.
Next, a description will be made regarding an operation of a receiver with reference to FIG. 4B. A despreader 411 multiplies a received signal by an orthogonal code assigned to a specific channel to despread the orthogonally spread signal received from the transmitter. An accumulator 412 accumulates the low rate channel signals outputted from the despreader 411 at periods of one symbol. A
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pattern generator 413 generates the same pattern as that of the pattern generator 405 in the transmitter. A multiplier 414 multiplies an output of the accumulator 412 by an output of the pattern generator 413. Here, the multiplier 414 and the pattern generator 413 constitute a pattern detector. A delay 415 delays an output signal of the multiplier 414 by one symbol period. A subtracter 416 subtracts a present low rate channel symbol value outputted from the multiplier 414 from a previous low rate channel symbol value outputted from the delay 415, to calculate a difference between the two symbols. A squarer 417 squares the difference value between the two symbols, outputted from the subtracter 416, to detect the non-orthogonal noise power. A down-sampler 418 down-samples the noise power between the specific symbols, outputted from the squarer 417. Also, the squarer 418 selects the non-orthogonal noise power between the specific symbols from the output of the squarer 417. A filter 419 bandpass filters the non-orthogonal noise power outputted from the down-sampler 418. The filter 419 can be composed of an IIR (Infinite Impulse Response) or FIR (Finite Impulse Response) filters to attain an appropriate bandwidth.
In operation, the received signal being a PN despread baseband signal is multiplexed by an orthogonal code for the sync channel to be despread and converted into symbol unit signals at the spreader 411 and the accumulator 412. The converted symbol unit signals are multiplied, at the multiplier 414, by the same pattern as that used in the transmitter. An output of the multiplier 414 is provided in common to the delay 415 and the subtracter 416. The subtracter 416 then subtracts the present symbol from the previous symbol outputted from the delay 415 to calculate the difference between the two symbols. Here, the difference value outputted from the subtracter 416 becomes a non-orthogonal noise component,
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Which is inputted to the squarer 417 to calculate the non-orthogonal noise power. The square 417 squares the difference values for the I and Q-channels to generate the non-orthogonal noise power. The down-sampler 418 has the function of detecting an output of the squarer 417 in the unit of two symbols. An output of the down-sampler 418 is applied to the filter 419 which controls a bandwidth of the non-orthogonal noise component. The filter 419 bandpass filters the non-orthogona! noise component to output non-orthogonal noise power at periods of a specific duration.
FIG. 10 shows a receiver for measuring non-orthogonal noise power according to another embodiment of the present invention. A despreader 1011 despreads an orthogonally spread signal by multiplying a received signal by an orthogonal code assigned to a speftc channel. Specifically, the despreader 1011 despreads the received spread low rate channel signal by multiplying the received signal by an orthogonal code assigned to the specific channel. An accumulator 1012 accumulates the low rate channel signal output from the despreader 1011 in a unit of one symbol. Here, the accumulator 1012 accumulates the despread low rate channel symbols by accumulating the signal despread at one tow rate channel symbol duration in a unit of a high rate channel symbol duration. A specific pattern generator 1013 generates the same pattern as that of the pattern generator 405 in the transmitter. A multiplier 1014 multiplies an output of the accumulator 1012 by an output by an output of the pattern generator 1013. Here, the multiplier 1014 and the pattern generator 1013 constitute a pattern detector. An operation hereto is the same as that of the receiving device of FIG.4B.
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The despread symbols are provided to a delay 1015 and a gain controller 1018. The receiver of FIG. 10 includes delays capable of storing several despread symbols to store symbols as many as the last received repeated symbol NUM_ SYM . To receive symbols of the sync channel shown in FIG. 2, the receiver of FIG. 10 may include three delays 1015,1016 and 1017. In this case, the delays 1015, 1016 and 1017 each have three delay elements so that they can store three previous symbols with respect to a present symbol. Here, the number of the delay elements is equal to or Jower than a frequency of transmissions.
For convenience, a present despread symbol will be referred to as Xn, a one symbol previous symbol Xn-1. a two-symbol previous symbol Xn-2 and a three-symbol previous symbol Xn-3. In this manner, a k-symbol previous symbol previous symbol will be referred to an Xn-k. Then, a present input symbol and symbols stored in the delays 1015-1017 are multiplied at the gain controllers 1018-1022 by corresponding gain control values Cn-C3, respectively, and then added at an adder 1023. An output of the adder 1023 can be defined as

In Equation 2, gain control values are set to be C0+C1+....Ck*=: 0. Since the transmitter repeats data symbols several times before transmission, the value Yn of Equation 2 should be zero in a noise-less environment.
In the embodiment of FIG. 10, since k=3, Equation 2 can be rewritten as:
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The Yn value calculated at the last symbol of the above repetitive duration should be zero in the noise-less environment. However, when the received symbol includes a non-orthogonal noise component, the value Yn may have a non-zero value due to the non-orthogonal noise component. In this case, the non-orthogonal noise power required by the receiver can be calculated squaring the value Yn and averaging the squared value for a predetermined time.
Although a description has been made regarding a case where non-orthogonal noise power is calculated depending on only the Yn value in the embodiment of FIG. 10, it is also possible to measure the non-orthogonal noise power by calculating Yn' using other coefficients C0,' C1,' C2', C3' (Co,+ C1,+ C2+ C3-0). In this case, although complexity and calculations of the receiver increase, it is possible to measure the non-orthogonal noise power more accurately.
A squarer 1024 squares the value Yn output from the adder 1023 to detect energy of the non-orthogonal noise component. A down-sampler 1025 then down-samples noises among specific symbols, output form the squarer 1024. From an output of the squarer 1024, the down-sampler 1025 selects the specific symbols and the non-orthogonal noise power among the symbols. In this case, the down-sampler 1025 should not select the non-orthogonal noise components generated at the boundary of the low rate channel. A filter 1026 bandpass filters an output of the down-sampler 1025 to output the non-orthogonal noise power.
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With reference to FIG. 5, there is illustrated a baseband receiver which process complex signals including I and Q-channel components. For convenience, a detailed description of the baseband receiver will be avoided herein. The baseband receiver includes an automatic gain controller (AGC) 512, a searcher 514, M fingers 521-52M, and a combiner and SIR measurer 532.
The AGC controller 512 measurers energy of an input signal to generate a gain control signal for controlling a gain of an AGC amplifier. A searcher 514 searches for a high-power multipath component to which a finger is to be assigned after initial acquisition and cell search. The fingers 521-52M demodulate multipath components assigned by the searcher 514 and measure local SIRs of the demodulated multipath components. The combiner and SIR measurer 532 combines the local SIRs calculated by the fingers 521-52M to calculate an effective SIR of the overall receiver, thereby to determine a power control command.
In the SIR measuring and power control method, the respective fingers 521-52M in the receiver for the CDMA system which divides the forward link channels
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using orthogonal codes, despread the received signals with the orthogonal codes assigned to the corresponding channels to measure interference components, and calculate the local SIRs. The combiner and SIR measurer 532 then calculates the effective SIR of the receiver by combining the local SIRs of the respective fingers 521-52M. The effective SIR is compared with a threshold. Based on the comparison, when the SIR is higher than the threshold, a power-down command for decreasing the forward link is generated; when the SIR is lower than the threshold, a power-up command for increasing the forward link.
A. First Embodiment
With reference to FIG. 6, there is illustrated in detail a finger for measuring an SIR by measuring energy of input components. In FIG. 6, all the signals are complex signals.
Referring to FIG. 6, a multiplier 611 despreads an input signal by mixing the input signal with a PN sequence. A channel estimator 613 estimates strength and phase of a multipath channel response from the despread pilot signal. A complex conjugator 615 complex conjugates an output of the channel estimator 613. A multiplier 617 multiplies an output of the multiplier 611 by a Walsh code for the traffic channel, to extract the traffic channel data. An accumulator 619 accumulates traffic channel signal outputted from the multiplier 617 in the symbol unit to output an intended data component. A multiplier 621 multiplies an output of the complex
conjugator 615 by an output of the accumulator 619 to output data symbols to the
symbol combiner 532 .
A signal energy detector 623 squares the respective signal components
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outputted from the accumulator 619 (I2+Q2) to calculate the signal energy. A filter 625 filters the signal energy outputted from the signal energy detector 623 to output a received signal component of the corresponding finger.
Interference power is detected by a non-orthogonal noise measurer 630 having the same structure as in FIGs. 3 and 4. In FIG. 6, the non-orthogonal noise measurer 630 employs the configuration of FIG. 3. The non-orthogonal noise component measured by the non-orthogonal noise measurer 630 is provided to a demultiplier 627 which demultiplies (or divides) the non-orthogonal noise component by a signal component outputted from the filter 625 to generate a local SIR signal of the corresponding finger.
As described above, the finger of FIG. 6 calculates the symbol energy of the traffic channel, filters the calculated symbol energy and calculates the signal component. Further, the finger detects the non-orthogonal noise component according to the present invention and then, divides the non-orthogonal noise power by the signal power to calculate the local SIR.
With reference to FIG. 7, there is illustrated in detail the symbol combiner and SIR measurer 532 when the fingers have the structure of FIG. 6. Referring to FIG. 7, an adder (or XOR gate) 711 combines data symbols outputted from the respective fingers 521-52M. An adder (or XOR gate) 712 adds the local SIRs SIR1-SIRM outputted from the respective fingers 521-52M to output a total SIR, which
is compared with a threshold to determine a power control command. That is, in the
symbol combiner and SIR measurer 532, the adder 712 adds the local SIRs
measured by the respective fingers 521-52M to measure an effective SIR of the
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overall mobile station receiver. Further, the effective SIR is compared with a threshold. In accordance with the comparison, when the effective SIR is higher than the threshold, a power-down command for the forward link is generated; when the effective SIR is lower than the threshold, a power-up command for the forward link is generated.
In an IS-95 forward link, a pilot channel is transmitted via a forward channel to assist in initial acquisition and data demodulation, and a traffic channel sends a power control command via a reverse link at periods of 1.2msec by puncturing-after-insertion.
A mobile station may measure the signal power based on a power control command transmitted via the forward link. In the above SIR measuring method, it is possible to calculate traffic channel power depending on only energy of the power control command upon detection of a traffic signal.
Although FIGs. 6 and 7 show the case where the measured local SIRs of the respective fingers are combined, it is also possible to measure the SIR after combining signals of the respective fingers at the signal combiner.
B. Second Embodiment
With reference to FIG. 8, there is illustrated in detail a finger for measuring an SIR. In this embodiment, a signal gain inputted to the symbol combiner is controlled according to interference measured by a non-orthogonal noise measurer.
Referring to FIG. 8, a multiplier 811 despreads an input signal by mixing the
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input signal with a PN sequence. A multiplier 812 multiplies a despread signal outputted from the multiplier 811 by an orthogonal code for the pilot channel to separate a pilot signal. A channel estimator 813 estimates strength and phase of a multipath channel response signal being demodulated by the finger from the output of the multiplier 811. A complex conjugator 815 complex conjugates an output of the channel estimator 813. A multiplier 823 multiplies an output of a demultiplier 821 by an output of the complex conjugator 815 and provides its output to the symbol combiner and SIR measurer 532,
A multiplier 817 multiplies the despread signal outputted from the multiplier 811 by an orthogonal code assigned to the traffic channel to separate a traffic channel signal. An accumulator 819 accumulates the traffic channel signal outputted from the multiplier 817 in the symbol unit to output an indented data component, which is provided to the demultiplier 821.
Also, the despread signal outputted from the multiplier 811 is applied to a non-orthogonal noise measurer 630, which measures the non-orthogonal noise power in the above described manner and provides the measured non-orthogonal noise power to the demultiplier 821. Here, the non-orthogonal noise measurer 630 may have the structure of FIG. 3 or 4.
The demultiplier 821 divides the traffic signal power outputted from the accumulator 819 by the non-orthogonal noise power outputted from the non-orthogonal noise power measurer 630, to generate a local SIR signal of the corresponding finger. The output of the demultiplier 821 is provided to the
multiplier 823.
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With reference to FIG. 9, there is illustrated a symbol combiner and SIR measurer 532 according to the second embodiment, which processes the outputs of the fingers having the structure of FIG. 8. Referring to FIG. 9, an adder (or XOR gate) 912 adds data values outputted from the fingers 521-52M, and a power detector 914 detects output power of the adder 912 and outputs the detected output power as an SIR value, which is compared with a threshold to generate a power control command for the forward link.
When measuring the SIR in FIG. 9, a mobile station can measure the signal power based on the power control command transmitted via the forward link. In the above SIR measuring method, it is possible to calculate the traffic channel power depending on only the power control command upon detection of a traffic signal.
In sum, the non-orthogonal noise components detected by the non-orthogonal noise measurer can be used as an SIR to be measured in a reception device. Further, for forward link power control, the SIR measured in the reception device is compared with a threshold to determine whether to increase or decrease the forward link power. The SIRs measured at the respective fingers can be used in controlling gains of the fingers.
Although the present invention has been described with reference to the cases where the novel non-orthogonal noise measurer is applied to an IS-95 sync channel, it is also possible to apply the novel non-orthogonal noise measurer even to a low rate traffic channel or a pilot channel repeating the same symbols, which have the similar characteristic to that of the IS-95 sync channel. In addition, the novel non-orthogonal noise measurer can be equally applied even to a 3rd generation

CDMA communication system.
As described above, the novel CDMA communication system measures non-orthogonal noise power using a forward channel with no specific information or a low rate channel. This provides an effective non-orthogonal noise measuring method for a 3rd generation CDMA communication system, and the novel non-orthogonal noise measuring method can be applied to the IS-95 communication system without a modification in channel structure. In addition, the novel non-orthogonal noise measuring method can measure an accurate non-orthogonal noise component using all the orthogonal codes. So, it is possible to increase a performance of a reception device by increasing an accuracy of an SIR.
While the invention has been shown and described with reference to a certain preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
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WE CLAIM
1. A non-orthogonal noise detecting device for a code division multiple
access (CDMA) communication system, comprising:
a despreader for dispreading multiple channel signals including a specific channel with an orthogonal code assigned to the specific channel repeating at least two same second symbols at a given first symbol duration, to generate despread repeated symbols;
a difference signal generator for receiving the despread second symbols, and generating a difference signal between a presently received second symbol and a previously received second symbol; and
a noise detector for converting the difference signal to an energy value to generate
a non-orthogonal noise signal.
2. The non-orthogonal noise detecting device as claimed in claim 1, wherein
the despreader comprises:
an orthogonal demodulator for dispreading the received channel signal with an orthogonal code assigned to a channel for transmitting the first symbol, and
an accumulator for accumulating the symbols orthogonally modulated for the first symbol duration in a unit of the second symbol.
3. The non-orthogonal noise detecting device as claimed in claim 2, wherein
the difference signal generator comprises
a delay for delaying the second symbols output from the despreader; and
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a subtracter for subtracting the second symbols output from the despreader from the delayed second symbols to generate the non-orthogonal noise component.
4. The non-orthogonal noise detecting device as claimed in claim 3, wherein the
noise detector comprises:
a squarer for converting an output of the difference signal generator to an energy component; and
a filter for filtering an output of the squarer in a noise band to generate the non-orthogonal noise signal.
5. The non-orthogonal noise detecting device as claimed in claim 1,
comprising a down-sampler connected to the noise detector, for down-sampling the non-orthogonal noise signal so as not to select an output generated at a boundary duration of the first symbol as a non-orthogonal noise.
6. The non-orthogonal noise detecting device as claimed in claim 5, wherein
the first symbol is a sync channel and the second symbol is a traffic channel
symbol.
7. A non-orthogonal noise detecting device for a CDMA communication system,
comprising:
a despreader for dispreading a received signal with an orthogonal code for a sync channel.
an accumulator for accumulating the despread sync channel signal in a unit of
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traffic channel symbol duration.
a difference signal generator for delaying an output of the accumulator in a unit of traffic channel symbol duration and calculating a difference between the delayed traffic duration symbol signal and the despread traffic-duration symbol signal;
a non-orthogonal noise detector for converting the difference signal to an energy component to generate a non-orthogonal noise component; and
a down-sampler for receiving the non-orthogonal noise and down-sampling the received non-orthogonal signals so as not to select an output generated at a boundary of the sync channel symbol as a non-orthogonal noise, non
8. A non-orthogonal noise detecting device for a CDMA communication
system, comprising:
a despreader for despreadign multiple channel signals including a specific channel with an orthogonal code assigned to the specific channel repeating the same data, to generate despread repeated symbols;
a difference signal generator for receiving the despread repeated symbols, and detecting a difference between a presently received symbol and a previously received symbol; and
a noise detector for converting the difference signal to an energy component to
generate a non-orthogonal noise signal.
9. The non-orthogonal noise detecting device as claimed in claim 8, further
comprising a down-sampler connected to the noise detector, for down-sampling the non-
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orthogonal noise signals.
10. The non-orthogonal noise detecting device as claimed in claim 9, wherein
the channel repeating the same data is a pilot channel.
11. A non-orthogonal noise detecting method for a CDMA communication
system, comprising the steps of:
dispreading multiple channel signals including a specific channel with an orthogonal code assigned to the specific channel repeating at least two same second symbols at a given first duration, to generate despread repeated symbols;
receiving the despread second symbols, and generating a difference signal between a presently received second symbol and a previously received second symbol; and
converting the difference signal to an energy value to generate a non-orthogonal noise signal.
12. The non-orthogonal noise detecting method as claimed in claim 11,
wherein the dispreading step comprises the steps of:
dispreading the received channel signal with an orthogonal code assigned to a channel for transmitting the first symbol, and
accumulating the symbols orthogonally modulated for the first symbol duration in a unit of the second symbol.
13. The non-orthogonal noise detecting method as claimed in claim 12,
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wherein the difference signal generating step comprises the steps of:
delaying the second symbols; and
subtracting the second symbols from the delayed second symbols to generate the non-orthogonal noise component.
14. The non-orthogonal noise detecting device as claimed in claim 11, further
comprising the step of down-sampling the non-orthogonal noise signal so as not to select
an output generated at a boundary duration of the first symbol as a non-orthogonal noise.
15. The non-orthogonal noise detecting device as claimed in claim 11, wherein
the first symbol is a sync channel symbol and the second is a traffic channel
symbol.
16. A non-orthogonal noise detecting method for a CDMA communication
system, comprising the steps of:
dispreading multiple channel signals including a specific channel with an orthogonal code assigned to the specific channel repeating the same data, to generate dispread repeated symbols;
receiving the despread repeated symbols, and detecting a difference between a presently received symbol and a previously received symbol; and
converting the difference signal to an energy component to generate a non-orthogonal noise signal.
17. The non-orthogonal noise detecting method as claimed in claim 16, further
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comprising the step of down-sampling the non-orthogonal noise signals
18. A non-orthogonal noise detecting device for a CDMA communication
system, comprising:
3 channel coder(402) for coding a specific traffic channel signal being
transmitted at a lower rate as compared with other channel signals;
a pattern inserter(405, 406) for inserting a specific pattern in an output of the
channel coder;
a base station device(408) including a spreader for spreading an output of the
pattern inserter with an orthogonal code for a corresponding channel;
a despreader(411) for despreading multiple channel signals including a specific
channel with an orthogonal code assigned to the specific channel repeating at
least two same second symbols at a given first symbol duration, to generate
despread repeated symbols;
a pattern renover(413, 414) for removing the specific pattern from the despread
signal;
a difference signal generator(415, 416) for receiving the pattern-removed second
symbols, and generating a difference signal between a presently received second
symbol and a previously received second symbol; and
a noise detector{417) for converting the difference signal to an energy value to
generate a non-orthogonal noise signal,
19. The non-orthogonal noise detecting device as claimed in claim 18, further
comprising a down-sampler for down-sampling the non-orthogonal noise signal
so as not to seiect an output generated at a boundary duration of the first
symbol as a non orthogonal noise.

20. The non-orthogonal noise detecting device as claimed in claim 19, wherein
the first symbol is a sync channel symbol and the second is a traffic channel
symbol.
21. A non-orthogonal noise detecting device for a CDMA communication
system, comprising:
a despreader for dispreading multiple channel signals including a specific channel with an orthogonal code assigned to the specific channel repeating k same second symbols at a given first symbol duration, to generate despread repeated symbols; a non-orthogonal noise operator for delaying the despread second symbols by k-1, applying a predetermined gain control value to the present symbol and the (k-1) delayed second symbols, and operating the gain-controlled second symbols to generate a non-orthogonal noise component;
a noise detector for converting the difference signal to an energy value to generate a non-orthogonal noise signal.
22. The non-orthogonal noise detecting device as claimed in claim 21, wherein
the despreader comprises:
an orthogonal demodulator for dispreading the received channel signal with an orthogonal code assigned to a channel for transmitting the first symbol; and an accumulator for accumulating the symbols orthogonally modulated for the first symbol duration in a unit of the second symbol.
23. The non-orthogonal noise detecting device as claimed in claim 22, wherein
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the non-orthogonal noise operator comprises:
(K-l) delays connected in cascade, for delaying the second symbols output from the despreader;
gain controllers for multiplying the received second symbol and the (k-l) delayed second symbols by predetermined corresponding gain control values, wherein the sum of the gain control values become zero; and
an adder for adding outputs of the gain controllers to generate the non-orthogonal noise component.
24. The non-orthogonal noise detecting device as claimed in claim 21 or 23,
farther comprising a down-sampler connected to the noise detector, for down-sampling the non-orthogonal noise signal so as not to select an output generated at a boundary duration of the first symbol as a non-orthogonal noise.
25. The non-orthogonal noise detecting device as claimed in claim 24, wherein
the first symbol is a sync channel symbol and the second symbol is a traffic channel symbol.
26. A non-orthogonal noise detecting method for a CDMA communication
system, comprising:
despreading multiple channel signals including a specific channel with an orthogonal code assigned to the specific channel repeating k same second symbols at a given first symbol duration, to generate desperead repeated symbols;
delaying the despread second symbols by k-l, applying a predetermined gain
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control value to the present symbol and the (k-1) delayed second symbols, and operating the gain-controlled second symbols to generate a non-orthogonal noise component;
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converting the difference signal to an energy value to generate a non-orthogonal noise signal.
A non-orthogonal noise detecting device for a CDMA communication system. In the device, a despreader 311, despreads multiple channel signals including a specific channel with an orthogonal code assigned to the specific channel repeating at least two same second symbols at a given first symbol duration, to generate despread repeated symbols. A difference signal generator 317 receives the despread second symbols, and generates a difference signal between a presently received second symbol and a previously received second symbol. A noise detector 323 converts the difference signal to an energy value to generate a non-orthogonal noise signal.

Documents:

00546-cal-1999-abstract.pdf

00546-cal-1999-claims.pdf

00546-cal-1999-correspondence.pdf

00546-cal-1999-description(complete).pdf

00546-cal-1999-drawings.pdf

00546-cal-1999-form-1.pdf

00546-cal-1999-form-18.pdf

00546-cal-1999-form-2.pdf

00546-cal-1999-form-3.pdf

00546-cal-1999-form-5.pdf

00546-cal-1999-g.p.a.pdf

00546-cal-1999-letters patent.pdf

00546-cal-1999-priority document others.pdf

00546-cal-1999-priority document.pdf

00546-cal-1999-reply f.e.r.pdf

546-CAL-1999-FORM-27.pdf


Patent Number 202472
Indian Patent Application Number 546/CAL/1999
PG Journal Number 08/2007
Publication Date 23-Feb-2007
Grant Date 23-Feb-2007
Date of Filing 14-Jun-1999
Name of Patentee SAMSUNG ELECTRONICS CO., LTD,
Applicant Address 416,MAETAN-DONG ,PALDAL-GU, SUWON-CITY KYUNGKI-DO
Inventors:
# Inventor's Name Inventor's Address
1 HI-CHAN MOON 391, PUNGNAP-DONG ,SONGPA-GU SEOUL
2 JONG-HAN KIM BYEOKSAN APT.,202-1103,JUKJEON-RI, SUJI-UP YONGIN-SHI, KYONGGI-DO
PCT International Classification Number H 04 B 1/69
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 22215/1998 1998-06-13 Republic of Korea