Qin J Wang

US Patent:

6542551, Apr 1, 2003

Filed:

May 20, 1999

Appl. No.:

09/315475

Inventors:

Yuri Okunev - Southbury CT
Vitaly Drucker - Stamford CT
Qin Wang - Bristol CT
Yuri Goldstein - Southbury CT

Assignee:

PC Tel, Inc. - San Jose CA

International Classification:

H04B 1404

US Classification:

375242, 370523

Abstract:

The receiver of a PCM modem utilizes the V. 90 TRN training signal for detecting whether any of the six slots of the received signal may be subject to alternating robbed bit signaling (ARBS), and what the alternating robbed bit signaling pattern may be. This is accomplished by accumulating the received level over a plurality of frames for each slot and by comparing the received levels for each slot to an average level for that slot. If the difference between the received levels and the average levels exceeds a threshold, the slot is determined to be subject to ARBS. Where a slot is subject to ARBS, DIL sequence signals for frames of the alternating robbed bit signaling slot having LSB=0 and LSB=1 are accumulated separately (if available) in order to generate two translation tables (TRT , TRT ) for that slot. Where the DIL sequence is found only in the frames having the alternating robbed bit signaling slot having LSB=0 or having LSB=1, only one translation table can be generated. Different algorithms are provided for designing a constellation for the alternating robbed bit signaling slot depending on (a) whether two translation tables were generated for the slot, (b) whether the frame-to-TRT correspondence is known, and (c) where only one translation table is generated, whether the translation table generated was TRT or TRT.

US Patent:

6560277, May 6, 2003

Filed:

Feb 9, 2001

Appl. No.:

09/780200

Inventors:

Yuri Okunev - Southbury CT
Vitaly Drucker - Stamford CT
Qin Wang - Bristol CT
Yuri Goldstein - Southbury CT

Assignee:

PC Tel, Inc. - Milpitas CA

International Classification:

H04B 516

US Classification:

375222, 370523

Abstract:

A method for determining the encoding law of an incoming signal in a network which possibly contains an A- or -A conversion includes obtaining digital impairment learning (DIL) probing data, generating an ordered table of levels therefrom, using the table to find two functions, and using a logical analysis of the functions to determine the encoding law of the signal. A first function is a maximum from the values DL(i) and the threshold Th which are less than T(i), with T(i)=a+bi, and DL(i)=L(i+ )- L(i) with L(i) being the DIL signal corresponding to the transmitted Ucode=i. A second function Q is defined by: where DLm(i) is the median value of a windowed group of values for DL(i) where i ranges from i5 to i6, Ly=i6-i5-1, and S is a mean of a windowed group of slopes, wherein each slope relates to the difference between certain DLm(i) values.

US Patent:

6778597, Aug 17, 2004

Filed:

May 5, 2003

Appl. No.:

10/430178

Inventors:

Yuri Okunev - Southbury CT
Vitaly Drucker - Stamford CT
Qin Wang - Bristol CT
Yuri Goldstein - Southbury CT

Assignee:

PCTEL, Inc. - Chicago IL

International Classification:

H04B 516

US Classification:

375222, 370523

Abstract:

A method for determining the encoding law of an incoming signal in a network which possibly contains an A- or -A conversion includes obtaining digital impairment learning (DIL) probing data, generating an ordered table of levels therefrom, using the table to find two functions, and using a logical analysis of the functions to determine the encoding law of the signal. A first function is a maximum from the values DL(i) and the threshold Th which are less than T(i), with T(i)=a +bi, and DL(i)=L(i+16)-2L(i) with L(i) being the DIL signal corresponding to the transmitted Ucode=i. A second function Q is defined by: where DLm(i) is the median value of a windowed group of values for DL(i) where i ranges from i to i , Ly=i -i -1, and S is a mean of a windowed group of slopes, wherein each slope relates to the difference between certain DLm(i) values.

US Patent:

61782009, Jan 23, 2001

Filed:

Jan 28, 1999

Appl. No.:

9/238321

Inventors:

Yuri Okunev - Southbury CT
Vitaly Drucker - Stamford CT
Qin Wang - Bristol CT
Yuri Goldstein - Southbury CT

Assignee:

PCTEL, Inc. - San Jose CA

International Classification:

H04B 138
H04B 1404

US Classification:

375222

Abstract:

Modem constellations are designed by independently optimizing for each slot of a frame, the distances between constellation points used for that slot. A maximum number of points N(0) are chosen having at least the minimum distance d0 without exceeding a power limitation Plim. Using N(0), an attempt is made to increase the d0 in the constellation without exceeding Plim. Constellations may be further optimized by, where possible, decreasing N(0) in a particular constellation without affecting the total data rate of the frame. Thus, a maximum potentially achievable data rate Rmax is calculated given the number of points which are in each of the six constellations, and comparing Rmax to a standards-permitted data rate DR; and then, if Rmax exceeds DR, by decreasing N(0) in one or more constellations, provided the decrease in the number of points does not cause a recalculated Rmax to drop below DR. Further optimization is obtained by attempting to increase d0 in one or more slots by permitting that slot(s) to exceed Plim, provided the average power of the frame is not exceeded. This is accomplished by finding the slot with the maximum error probability, increasing d0 for that slot (while maintaining N(0)) to thereby exceed frame power limitations for that slot, and checking to see whether the changes to the constellation in that slot violates the average frame power limitations.

US Patent:

62721712, Aug 7, 2001

Filed:

Jan 28, 1999

Appl. No.:

9/238302

Inventors:

Yuri Okunev - Southbury CT
Vitaly Drucker - Stamford CT
Qin Wang - Bristol CT
Yuri Goldstein - Southbury CT

Assignee:

PC TEL, Inc. - San Jose CA

International Classification:

H04B 138
H04L 2706

US Classification:

375222

Abstract:

Methods are provided for determining whether any slots of a modem frame are subject to robbed bit signaling (RBS), and whether the robbed bit signaling is. beta. -codec robbed bit signaling. From an obtained DIL sequence, an ordered table of level values for each slot is generated. In determining whether any slots are RBS slots, distances between adjacent levels of the table for each slot are obtained and are compared to a "zero distance" threshold value in order to determine the number of distances which exceed the "zero distance" value. For each slot, the number of zero distances are compared to a threshold value, and if the number of zero distances exceeds the threshold value, the slot is declared to be a RBS slot. Zero distance thresholds for each slot are generated by finding a function of a maximum distance for that slot among the adjacent levels. In determining whether any RBS slots are. beta.