WO1997005717A1 - Apparatus and method for rate determination in on-off variable-rate communication systems - Google Patents
Apparatus and method for rate determination in on-off variable-rate communication systems Download PDFInfo
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- WO1997005717A1 WO1997005717A1 PCT/US1996/010130 US9610130W WO9705717A1 WO 1997005717 A1 WO1997005717 A1 WO 1997005717A1 US 9610130 W US9610130 W US 9610130W WO 9705717 A1 WO9705717 A1 WO 9705717A1
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- WIPO (PCT)
- Prior art keywords
- rate
- metric
- selecting
- symbol energy
- computing
- Prior art date
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- 238000004891 communication Methods 0.000 title claims abstract description 21
- 238000000034 method Methods 0.000 title claims description 38
- 230000005540 biological transmission Effects 0.000 description 19
- 239000013598 vector Substances 0.000 description 12
- 230000008569 process Effects 0.000 description 10
- 230000000694 effects Effects 0.000 description 7
- 230000001413 cellular effect Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 230000007480 spreading Effects 0.000 description 4
- 230000008859 change Effects 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 238000013459 approach Methods 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000005094 computer simulation Methods 0.000 description 2
- 125000004122 cyclic group Chemical group 0.000 description 2
- 238000010187 selection method Methods 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 238000007476 Maximum Likelihood Methods 0.000 description 1
- 230000010267 cellular communication Effects 0.000 description 1
- 230000001427 coherent effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 238000000638 solvent extraction Methods 0.000 description 1
- 208000011580 syndromic disease Diseases 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
- H04B17/30—Monitoring; Testing of propagation channels
- H04B17/309—Measuring or estimating channel quality parameters
- H04B17/336—Signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR]
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
-
- 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
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
- H04B17/20—Monitoring; Testing of receivers
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
- H04W16/18—Network planning tools
Definitions
- the present invention relates to rate determination in variable rate communications systems, and more particularly, to rate determination in communications systems in which on-off or amplitude-modulated keying is used to implement the variable-rate transmission scheme.
- GSM Groupe Special Mobile
- ETSI European Telecommunications Standards Institute
- a voice activity detector in the digital speech encoder used to encode each user's voice disables the user's transmitter when he or she is not speaking.
- DTX discontinuous Transmission
- this technique offers the important benefit of reduced mobile station battery consumption, and nominally permits smaller radio frequency (RF) channel reuse distances (since the mean co-channel interference power is reduced), thereby increasing system capacity.
- RF radio frequency
- TIA Standard IS-95-A describes different tecnniques for achieving this on each of the forward link (base station to mobile station) and the reverse link (mobile station to base station), but only the method used on reverse link is relevant to this discussion.
- the mobile station (MS) partitions the 8kHz pulse code modulated (PCM) user voice signal (100) into 20ms segments or frames and then encodes those frames into information packets using a digital speech encoder (101).
- PCM pulse code modulated
- the exact specification of the digital speech encoder (101) appears in TIA Standard IS-96-A Speech Service Option Standard for Wideband Spread Spectrum Digital Cellular System.
- each frame is classified by a voice activity detector (107) associated with the digital speech encoder (101) as belonging to one of four distinct transmission rates. These are labeled here as “rate- /1", “rate-1/2", “rate-1/4", and “rate-1 /8". Again, a precise description of the voice activity detector (107) appears in TIA Standard IS-96-A. It is sufficient to state that the speech encoder (101) uses more information bits to encode frames which occur during active talk spurts, and fewer bits during silence periods. Rate-1/1 uses most information bits while rate-1/8 uses fewest. Bit usage for frames encoded at rates-1 /2 and -1/4 - which generally occur during transitions between active talk spurts and silence periods - lie somewhere between these limits.
- the result of the frame classification process is indicated to the digital speech encoder (101) by the rate indicator (108) generated by the voice activity detector (107).
- the rate-1/1 and rate-1/2 packets are then subject to block or cyclic coding (102) as specified in TIA Standard IS-95- A section 6.1.3.3.2.1 Reverse Traffic Channel Frame Quality Indicator.
- block or cyclic coding 102 as specified in TIA Standard IS-95- A section 6.1.3.3.2.1 Reverse Traffic Channel Frame Quality Indicator.
- channel coding (103) which is specified as a rate-1/3 convolutional code in TIA Standard IS-95-A section 6.1.3.1.3 Convolutional Encoding.
- the number of channel- encoded bits forming an encoded packet (104) is listed in Table 1.
- each encoded packet is further prepared for transmission by using 64-ary orthogonal modulation followed by direct sequence spreading using a 1.2288Mc/s user-specific pseudo-noise (PN) code (105) (see TIA Standard IS-95-A sections 6.1.3.1.6 Orthogonal Modulation and 6.1.3.1.9 Quadrature Spreading).
- PN pseudo-noise
- Table 1 since the modulation scheme is 64- ary orthogonal, 96 symbols (commonly referred to as Walsh symbols) are required to transmit rate-1/1 packets. Likewise, 48 symbols are required for rate-1/2 transmission, 24 symbols are required for rate-1/4 transmission, and 12 symbols are required for rate-1/8 transmission.
- TIA Standard IS-95-A specifies that the symbols be transmitted in bursts of 6 consecutive Walsh symbols.
- the TIA Standard IS-95-A sub-divides each 20ms traffic channel frame into 16 groups, known as "Power Control Groups" (PCG's), each capable of transmitting a single group of 6 Walsh symbols (see TIA Standard IS-
- Fig. 2 shows transmitter activity during a 20ms traffic channel frame (200) for each of the possible packet sizes or rates.
- shading of a PCG interval (201) implies that a burst of 6 direct sequence spread Walsh symbols was transmitted during that PCG.
- the selected packet rate is rate-1/1
- all 16 PCG's in a 20ms traffic channel frame will be active as shown by case (202) of Fig. 2.
- the MS transmitter will be active during only 8 PCG's as shown by case (203).
- a rate-1/4 packet will generate the active PCG's shown in case (204), while the rate-1/8 case is shown as case (205).
- the PCG's which are active in any given 20ms frame are determined from a pseudo-random PCG selection procedure driven by observations of the user-specific PN code during the traffic channel frame preceding the frame under analysis as described in TIA Standard IS-95-A section 6.1.3.1.7.2 Data Burst Randomizing Algorithm. Specifically, the last 14 bits of the user- specific PN code generated during the next to last PCG of the previous frame are stored, and used to select the PCG's that will be active, for each transmission rate, in the following frame.
- the position of the active PCG's in any particular traffic channel frame therefore depends on the time at which the frame is transmitted, the identity of the user, and the rate of the packet transmitted during that frame.
- the number of active PCG's remains unchanged for each rate - only the position of the active PCG's change pseudo-randomly with time and user identity.
- the base station (BS) receiver must re-generate the user-specific PN code used at the MS to perform direct sequence spreading. Accordingly, the BS receiver can also unambiguously identify the PCG's used to transmit a packet at any of the four possible rates. Further, since the PCG selection procedure depends only on the user-specific PN code sequence observed during the previous frame, the BS receiver can identify the active PCG's for the current frame at the start of the current frame. By using this method of variable-rate transmission, TIA Standard IS-95-A mobile stations are able to reduce battery consumption, and the average amount of interfering power presented to other IS-95-A mobile stations using the same carrier frequency.
- Prior methods of performing rate determination include the technique implemented in the Base Station Modem (BSM) chipset manufactured by Qualcomm Inc, of San Diego, CA for use in TIA Standard IS-95-A compliant base station receivers.
- BSM Base Station Modem
- the procedure begins by first converting (300,301) the received radio frequency (RF) waveform comprising each direct sequence spread Walsh symbol from an RF signal to a baseband signal sampled at the chip rate.
- RF radio frequency
- IF intermediate frequency
- baseband functions such as frequency conversion, automatic gain control, symbol sampling etc., but these need not be specified here in detail.
- Each transmitted Walsh symbol waveform is then recovered, after being corrupted by noise and distorted by the communication channel, by despreading (302) which requires correlation with the user-specific PN sequence (303) used to spread the transmitted Walsh symbols.
- Walsh symbol detection is then performed (304) using the well-known method of correlating the received Walsh symbol waveform against the set of 64 waveforms comprising the symbol alphabet in a 64-ary correlator (312).
- the precise details of this technique and its performance are very well known and are described in standard texts on digital communications, including Digital Communications by J.G. Proakis.
- the maximum likelihood method of identifying the transmitted Walsh symbol when no received signal phase reference is available is to select that correlator and corresponding symbol index which maximizes the magnitude of the complex-valued cross-correlation between the 64 possible symbol waveforms and the received waveform.
- This selection process is performed in the block marked 'Max' (313) in Fig. 3.
- the magnitude- square value of that maximum magnitude cross-correlation result is referred to here as the "maximum Walsh symbol energy" or MWSE and is shown being generated as output (315).
- the index (314) corresponding to the correlator which gave the maximum magnitude correlator output is then passed to the block deinterleaver (305) where the channel symbols comprising each Walsh symbol are deinterleaved and convolutionally decoded (306) using the well-known Viterbi algorithm.
- the deinterleaving and Viterbi decoding processes (305) and (306) are performed four times - once under the hypothesis that each possible packet transmission rate was used.
- Viterbi decoding (306) an estimate of the number of channel symbol errors present in the received packet is computed for each of the four possible rates by the well-known method of comparing the received channel encoded symbols with those obtained by convolutionally re-encoding the Viterbi decoder output for each rate.
- a 4-ary vector (308) containing the estimated number of symbol errors by rate is then passed to the rate determination function (309).
- the block or cyclic codes associated with rate-1/1 and rate-1/2 packets (referred to in TIA Standard IS-95-A as the Frame Quality Indicators) are decoded (307) and their syndromes or checksums (as defined in Error Control Coding by S. Lin, and D.J. Costello) made available to the rate determination function (309) as a 2-ary vector (310).
- Rate determination is then performed by partitioning the 6-ary decision space formed by the 4-ary symbol error count and 2-ary checksum vectors (309) and (310), and then estimating the transmitted rate by identifying the region of the decision space in which the 6-ary vector corresponding to the received packet lies. If the rate of the transmitted packet cannot be confidently established (i.e. it lies outside the decision regions of all four rates), the packet may be declared "erased". No further processing, such as speech decoding, is performed on such packets.
- FIG. 1 shows generally a prior art method of performing speech and channel coding, and modulation and direct sequence spreading of the reverse link traffic channel frame in a communication system having a variable-rate speech service option.
- FIG. 2 shows an example of the prior art power control group (PCG) structure of a particular frame of the reverse link traffic channel frame when the variable-rate speech service option is in use.
- PCG power control group
- FIG. 3 shows a prior art method of rate determination for the reverse link traffic channel packets.
- FIG 4 is a block diagram illustrating a preferred implementation of a rate determination apparatus in accordance with the present invention.
- FIG. 5 is a block diagram illustrating an alternate preferred implementation of a rate determination apparatus in accordance with the present invention.
- FIG. 4 shows the process of RF conversion (300,301) and despreading (302) used to recover the noisy orthogonal waveform corresponding to each transmitted Walsh symbol comprising a traffic channel frame. Also shown is the user-specific PN code generator (303) used to generate the despreading sequence, and the Walsh symbol detector (304) comprising the 64-ary correlator (312) and selector function (313). The Walsh symbol detector is shown generating the maximum Walsh symbol energy (MWSE) value (315).
- MWSE maximum Walsh symbol energy
- the MWSE for each received Walsh symbol is then passed to four accumulators (409-412), labeled in abbreviated fashion "R-l /1 Ace.” (409) through “R-l/8 Ace.” (412) for "rate-1/1 accumulator” (409), etc.
- the contents of these accumulators are uniformly set to zero at the start of each traffic channel frame.
- the adders (405-408) associated with each accumulator are gated by control signals from the PCG selector function (400), and only accumulate the MWSE when the corresponding PCG flag has logical value '1'.
- the PCG selector function (400) observes the output of the user-specific PN code generator over the previous traffic channel frame and identifies, according to the method defined by TIA Standard IS-95-A section 6.1.3.1.7.2 Data Burst Randomizing Algorithm, the PCG's which would be active in the current traffic channel frame for each possible transmitted rate.
- the PCG selector (400) outputs 4 binary flags (401-404) labeled "rate-1/1 PCG flag" through "rate-1/8 PCG flag". These flags are logically '1' if and only if the Walsh symbol being demodulated by the detector (304) is a member of an active PCG for the rate associated with that flag.
- the rate-1 /2 PCG flag is logically '1' only during the shaded portions of the traffic channel frame corresponding to case (203).
- the rate-1 /4 PCG flag only has value '1' during the shaded periods of case (204), and so on. This process continues until all 96 Walsh symbols comprising a frame have been received. At the end of the frame, therefore, the accumulator labeled "R-l /1 Ace.” has accumulated 96 MWSE values, the "R-l/2 Ace.” has accumulated 48 MWSE values, the "R-l /4 Ace.” has accumulated 24 MWSE values, and "R-l/8 Ace.” has accumulated 12 MWSE values.
- each subtractor (417-420) is then fed to a selector (421) which identifies the maximum of the four subtractor (417-420) outputs. This uniquely identifies which of the accumulators (409-412) led to the maximum value at the selector (421).
- the estimated transmission rate (422) is then identified as that corresponding to the accumulator (409-412) which produced that maximum value at the selector (421).
- the estimated rate (422) is used to control operation of the deinterleaver (423) and Viterbi decoder (424). These devices execute only once to decode the received channel symbols according to the rate predicted by the estimated rate (422).
- the scalar values M-l/1 through M-l/8 (413-416) are established beforehand by computer simulation or by bench testing. They are, in-practice, generally constant throughout the duration of the traffic channel frame under analysis. They may, however, change in value at each Walsh symbol boundary, depending on other parameters associated with the base station receiver.
- a "rake" receiver to exploit the presence of multipath signal components in the communications channel. [Rake receivers are well known in the art and need not be described here.]
- each element (500) comprises at least a despreader (302) and 64- ary correlator (312). Note that more or less elements (500) than 4 may be used depending on the application.
- each element is assigned to a distinct multipath signal component, with differences in the observed delay of each multipath signal component compensated by the delay elements ⁇ 1 - ⁇ 4 . (502-505).
- Each despread multipath signal component is then passed through a 64-ary correlator (312) of the same type as that described above.
- a 64-ary vector is then formed at the output of each correlator (312), where the i-th element of the 64-ary vector is the magnitude-square of the i-th correlator output.
- 4 such vectors are combined (522) by simple vector addition.
- the maximum Walsh symbol energy (MWSE) (315) is then identified (523) as the maximum-valued element of the resulting combined 64-ary vector, with the MWSE (315) subsequently used for rate-determination in the manner shown in Fig. 4.
- each multipath component may vary, however, with time. Accordingly, the number of elements (500) that are operating on multipath components which contribute significantly to the vector combining process (522) may change.
- the RF converter (301) incorporates an automatic gain control stage, the relative contribution of each element (500) can be estimated using a simple signal-noise ratio (SNR) estimator (501) such as that shown in Fig. 5.
- SNR estimator operates by comparing the MWSE (506-509) of the individual 64-ary vectors at the output of each element's correlator (312) to a threshold T (510).
- the MWSE (506-509) of a particular element exceeds T (510), the corresponding 64-ary vector at the 64-ary correlator output of that element is included in the combining process (522), else it is excluded.
- An in-lock indicator for each element is shown in Fig. 5 as the binary lock flags L1-L4 (515-518).
- a counter which accumulates the number of elements currently in-lock by observing L1-L4 (515-518). This count (520) is used to obtain the row address of a 4x4 lookup table (521).
- the columns of the table contain the values of M-l/1 (413) through M-l /8 (416) to be used according to the number of element in lock.
- the contents of the lookup table are established beforehand by computer simulation or by bench testing.
- the estimated rate (430) need not be exclusively determined from the metrics available at output of subtractors (417- 420) in Fig. 4. Instead these metrics could be used as supplementary information for rate determination based upon, for example, symbol error rate or path metric information derived from the Viterbi decoder. It is also clear that the technique may readily be extended to estimate the rate of a variable-rate transmission derived from a information source other than speech. This might include variable- rate data transmission.
- the present invention provides a power and computation efficient apparatus and method for rate determination which does not negatively impact perceptual audio quality.
- further advantages and modifications will readily occur to those skilled in the art.
- the invention in its broader aspects, is therefore not limited to the specific details, representative apparatus, and illustrative examples shown and described herein.
- Various modification and variation can be made to the above specification without varying from the scope or spirit of the invention, and it is intended that the present invention cover all such modifications and variations provided they come within the scope of the following claims and their equivalents.
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Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
KR1019970701918A KR970706665A (en) | 1995-07-25 | 1996-06-12 | APPARATUS AND METHOD FOR RATE DETERMINATION IN VARIABLE VARIABLE-RATE COMMUNICATION SYSTEMS |
JP50758397A JP3251591B2 (en) | 1995-07-25 | 1996-06-12 | Apparatus and method for rate determination in on / off variable rate communication system |
FI970963A FI115177B (en) | 1995-07-25 | 1997-03-06 | Apparatus and Method for Determining Speed in Variable Speed Communication Systems Using Interrupt Keying |
SE9701032A SE518954C2 (en) | 1995-07-25 | 1997-03-21 | Device and method for speed determination in variable speed on / off communication systems |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US50616795A | 1995-07-25 | 1995-07-25 | |
US08/506,167 | 1995-07-25 |
Publications (1)
Publication Number | Publication Date |
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WO1997005717A1 true WO1997005717A1 (en) | 1997-02-13 |
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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PCT/US1996/010130 WO1997005717A1 (en) | 1995-07-25 | 1996-06-12 | Apparatus and method for rate determination in on-off variable-rate communication systems |
Country Status (6)
Country | Link |
---|---|
JP (1) | JP3251591B2 (en) |
KR (1) | KR970706665A (en) |
CA (1) | CA2200599A1 (en) |
FI (1) | FI115177B (en) |
SE (1) | SE518954C2 (en) |
WO (1) | WO1997005717A1 (en) |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2343346A (en) * | 1998-08-31 | 2000-05-03 | Samsung Electronics Co Ltd | Determining the rate of received data in a variable rate communication system |
GB2305088B (en) * | 1995-09-04 | 2000-05-17 | Oki Electric Ind Co Ltd | Method and device for performing signal decision in a communication system |
GB2344731A (en) * | 1995-09-04 | 2000-06-14 | Oki Electric Ind Co Ltd | Identifying signal code rate in a communication system |
WO2000077995A1 (en) * | 1999-06-10 | 2000-12-21 | Qualcomm Incorporated | Method and apparatus for using frame energy metrics to improve rate determination |
EP1114530A1 (en) * | 1999-07-08 | 2001-07-11 | Samsung Electronics Co., Ltd. | Data rate detection device and method for a mobile communication system |
KR100371293B1 (en) * | 1999-12-08 | 2003-02-07 | 닛본 덴기 가부시끼가이샤 | Wireless communication device and method of predicting a frame rate in a cdma communication system |
WO2003065613A1 (en) * | 2002-01-31 | 2003-08-07 | Qualcomm Incorporated | Discontinuous transmission (dtx) detection |
US6934321B2 (en) | 2000-05-09 | 2005-08-23 | Nec Corporation | W-CDMA transmission rate estimation method and device |
US7228491B2 (en) | 2002-12-18 | 2007-06-05 | Sony Ericsson Mobile Communications Japan, Inc. | Signal processing device and signal processing method |
US7457324B2 (en) | 2000-02-23 | 2008-11-25 | Ntt Docomo, Inc. | Multi-carrier CDMA radio transmitting method and apparatus, and channel estimation method and apparatus for multi-carrier CDMA radio transmitting system |
US8462875B2 (en) | 2009-07-20 | 2013-06-11 | Mitsubishi Electric Corporation | Timing regenerating device |
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-
1996
- 1996-06-12 JP JP50758397A patent/JP3251591B2/en not_active Expired - Fee Related
- 1996-06-12 CA CA002200599A patent/CA2200599A1/en not_active Abandoned
- 1996-06-12 WO PCT/US1996/010130 patent/WO1997005717A1/en active IP Right Grant
- 1996-06-12 KR KR1019970701918A patent/KR970706665A/en not_active Application Discontinuation
-
1997
- 1997-03-06 FI FI970963A patent/FI115177B/en not_active IP Right Cessation
- 1997-03-21 SE SE9701032A patent/SE518954C2/en not_active IP Right Cessation
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Cited By (21)
Publication number | Priority date | Publication date | Assignee | Title |
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GB2305088B (en) * | 1995-09-04 | 2000-05-17 | Oki Electric Ind Co Ltd | Method and device for performing signal decision in a communication system |
GB2344731A (en) * | 1995-09-04 | 2000-06-14 | Oki Electric Ind Co Ltd | Identifying signal code rate in a communication system |
GB2344731B (en) * | 1995-09-04 | 2000-07-26 | Oki Electric Ind Co Ltd | Performing signal decision in a communication system |
GB2343346B (en) * | 1998-08-31 | 2000-11-08 | Samsung Electronics Co Ltd | Method and apparatus for determining rate of data transmitted at variable rates |
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GB2343346A (en) * | 1998-08-31 | 2000-05-03 | Samsung Electronics Co Ltd | Determining the rate of received data in a variable rate communication system |
WO2000077995A1 (en) * | 1999-06-10 | 2000-12-21 | Qualcomm Incorporated | Method and apparatus for using frame energy metrics to improve rate determination |
US6389067B1 (en) * | 1999-06-10 | 2002-05-14 | Qualcomm, Inc. | Method and apparatus for using frame energy metrics to improve rate determination |
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US6792041B1 (en) | 1999-07-08 | 2004-09-14 | Samsung Electronics Co., Ltd. | Data rate detection device and method for a mobile communication system |
EP1114530A1 (en) * | 1999-07-08 | 2001-07-11 | Samsung Electronics Co., Ltd. | Data rate detection device and method for a mobile communication system |
EP1114530A4 (en) * | 1999-07-08 | 2003-03-12 | Samsung Electronics Co Ltd | Data rate detection device and method for a mobile communication system |
KR100371293B1 (en) * | 1999-12-08 | 2003-02-07 | 닛본 덴기 가부시끼가이샤 | Wireless communication device and method of predicting a frame rate in a cdma communication system |
US6888810B2 (en) | 1999-12-08 | 2005-05-03 | Nec Corporation | Wireless communication device and method of predicting a frame rate in a CDMA communication system |
US7457324B2 (en) | 2000-02-23 | 2008-11-25 | Ntt Docomo, Inc. | Multi-carrier CDMA radio transmitting method and apparatus, and channel estimation method and apparatus for multi-carrier CDMA radio transmitting system |
US7492794B2 (en) | 2000-02-23 | 2009-02-17 | Ntt Docomo, Inc. | Channel estimation method and apparatus for multi-carrier radio transmitting system |
US6934321B2 (en) | 2000-05-09 | 2005-08-23 | Nec Corporation | W-CDMA transmission rate estimation method and device |
US6782059B2 (en) | 2002-01-31 | 2004-08-24 | Qualcomm Incorporated | Discontinuous transmission (DTX) detection |
WO2003065613A1 (en) * | 2002-01-31 | 2003-08-07 | Qualcomm Incorporated | Discontinuous transmission (dtx) detection |
US7228491B2 (en) | 2002-12-18 | 2007-06-05 | Sony Ericsson Mobile Communications Japan, Inc. | Signal processing device and signal processing method |
US8462875B2 (en) | 2009-07-20 | 2013-06-11 | Mitsubishi Electric Corporation | Timing regenerating device |
Also Published As
Publication number | Publication date |
---|---|
FI970963A0 (en) | 1997-03-06 |
SE518954C2 (en) | 2002-12-10 |
JP3251591B2 (en) | 2002-01-28 |
CA2200599A1 (en) | 1997-02-13 |
JPH10507333A (en) | 1998-07-14 |
SE9701032D0 (en) | 1997-03-21 |
FI115177B (en) | 2005-03-15 |
FI970963A (en) | 1997-03-06 |
KR970706665A (en) | 1997-11-03 |
SE9701032L (en) | 1997-05-23 |
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