公开(公告)号：CA2399076A1

公开(公告)日：2001-08-09

申请号：CA2399076

申请日：2001-02-01

Applicant: MOTOROLA INC

Inventor： KIM DAE-YOUNG ,  MEHRABANZAD SEPEHR ,  MAURER PATRICK

IPC: H04L27/00 ,  H04B7/005 ,  H04B14/04 ,  H04L25/49 ,  H04M11/00 ,  H04B14/06 ,  H04L5/16 ,  H04L25/34 ,  H04B1/38

Abstract: In a PCM modem system in which equivalence classes are used to communicate information from a transmitter to a receiver, a method is provided to solve the problem of 180~ phase reversals in the communications channel which resu lt in a garbled transmission. This is accomplished by remapping the equivalence classes into a form that can be differentially encoded and decoded such that equivalence class identity is not lost during a phase reversal of the channe l. Referring to Figure 2, an incoming bit stream (10) is applied to a modulus converter (12) which is in turn coupled to a mapping block (14) which maps t he output of the modulus converter to the type of structure shown in Figure 1 i n which each equivalence class is provided with a label that includes a sign b it and magnitude bits.

公开(公告)号：CA2397971A1

公开(公告)日：2001-08-09

申请号：CA2397971

申请日：2001-02-01

Applicant: MOTOROLA INC

Inventor： PILOZZI JOHN ,  KIM DAE-YOUNG ,  MEHRABANZAD SEPEHR

IPC: H04L29/08 ,  H04L1/00 ,  H04L25/03 ,  H04M11/00 ,  H04B1/38 ,  H04L5/16

Abstract: In a full duplex PCM modem system (10) having an analog (12) and digital (18 ) modem, a method and apparatus is provided for on-the-fly reconfiguring of analog (12) or digital (18) modem transmitter parameters without switching back to a retrain or startup mode. In one embodiment, the transmitter parameters for the analog modem (12) are modified to take into account chann el impairments, in which modified precompensation parameters are sent from the digital modem (18) to the analog modem (12) without switching out of the dat a mode. In another embodiment, transmit power levels sensed at the analog mode m (12) which are non-optimal are adjusted by new parameters sent from the digital modem (18) without having to switch back to the startup mode. In a further embodiment, transmitter parameters in the digital modem (18) are reconfigured to provide more an increased downstream data rate from the digital modem (18) upon sensing improvement in the quality of the downstream channel without switching back to the startup mode.

公开(公告)号：AU6882498A

公开(公告)日：1998-10-30

申请号：AU6882498

申请日：1998-04-03

Applicant: MOTOROLA INC

Inventor： EYUBOGLU M VEDAT ,  KIM DAE-YOUNG ,  TUNG CHIEN-CHENG

IPC: H03M5/00 ,  H04B14/04 ,  H04L25/49 ,  H04L27/18 ,  H04K1/10

Abstract: A system transmits digital information bits, which are encoded into a predefined number of signed symbols per frame from a transmitter (40) over a network (46) to a receiver, wherein the transmitted signed symbols have a desired spectral shape; the digital information bits being divided into a first predetermined number of magnitude information bits and a second predetermined number of sign information bits per frame, the transmitter including: a magnitude mapping device (50) for mapping the magnitude information bits to the predefined number of symbols; a sign bit encoder (52) for encoding the sign information bits into the predefined number of encoded symbol sign bits per frame; and a signal point selector (54), responsive to the magnitude mapping device and the sign bit encoder, which combines the symbol magnitudes and the encoded symbol sign bits to form the predefined number of transmitted signed symbols per frame.

公开(公告)号：EP1042861A4

公开(公告)日：2004-07-21

申请号：EP98959517

申请日：1998-11-19

Applicant: MOTOROLA INC

Inventor： KIM DAE-YOUNG

IPC: H04L1/00 ,  H04B3/46 ,  H04B14/04 ,  H04J3/12 ,  H04L25/03 ,  H04L25/48 ,  H04L25/49

CPC classification number: H04J3/125 ,  H04B14/04 ,  H04L25/4927

Abstract: A device an method for detecting digital impairments affecting an upstream pulse code modulation (PCM) channel in a digital communication network (36), involves: receiving, by a digital PCM modem (38) interconnected to the digital communication network (36), a random sequence of digital values selected from a constellation of digital values transmitted over the upstream PCM channel of the digital communication network (36); establishing distributions of the received digital values, each distribution corresponding to one of a plurality of time intervals; and deriving from the distributions the types of robbed bit signaling and digital loss affecting the upstream PCM channel of the digital communication network (36) for each time interval.

公开(公告)号：EP1256183A4

公开(公告)日：2003-07-02

申请号：EP01905357

申请日：2001-02-01

Applicant: MOTOROLA INC

Inventor： MEHRABANZAD SEPEHR ,  KIM DAE-YOUNG ,  PILOZZI JOHN

IPC: H04L29/08 ,  H04L1/00 ,  H04L25/03 ,  H04M11/00 ,  H04B1/38 ,  H04L5/14 ,  H04L5/16 ,  H04L25/49

CPC classification number: H04L25/03343 ,  H04L1/0001 ,  H04L2025/03808

Abstract: In a full duplex PCM modem system (10) having an analog (12) and digital (18) modem, a method and apparatus is provided for on-the-fly reconfiguring of analog (12) or digital (18) modem transmitter parameters without switching back to a retrain or startup mode. In one embodiment, the transmitter parameters for the analog modem (12) are modified to take into account channel impairments, in which modified precompensation parameters are sent from the digital modem (18) to the analog modem (12) without switching out of the data mode. In another embodiment, transmit power levels sensed at the analog modem (12) which are non-optimal are adjusted by new parameters sent from the digital modem (18) without having to switch back to the startup mode. In a further embodiment, transmitter parameters in the digital modem (18) are reconfigured to provide more an increased downstream data rate from the digital modem (18) upon sensing improvement in the quality of the downstream channel without switching back to the startup mode.

公开(公告)号：BR9814510A

公开(公告)日：2004-04-20

申请号：BR9814510

申请日：1998-11-13

Applicant: MOTOROLA INC

Inventor： KIM DAE-YOUNG ,  HUMBLET PIERRE A

IPC: H04L27/04 ,  H04B14/04 ,  H04L25/03 ,  H04L25/49

Abstract: A transmitter in an analog pulse code modulation (PCM) modem (12) which transmits analog levels over an analog channel (18) to produce constellation points at a quantization device (26), wherein the constellation points correspond to groups of data bits to be transmitted to a digital PCM modem (28), the transmitter includes: a transmitter device which selects for each group of data bits to be transmitted a constellation point corresponding to the group of data bits and transmits over the analog channel a level that will produce at the input to the quantization device the selected constellation point; wherein the constellation points are chosen from a transmit constellation consisting of a plurality of non-uniformly spaced constellation points that have substantially equivalent, minimized error probability, constellation point to constellation point.

公开(公告)号：CA2317554C

公开(公告)日：2003-08-05

申请号：CA2317554

申请日：1998-11-19

Applicant: MOTOROLA INC

Inventor： KIM DAE-YOUNG

IPC: H04L1/00 ,  H04B3/46 ,  H04B14/04 ,  H04J3/12 ,  H04L25/03 ,  H04L25/48 ,  H04L25/49 ,  H03D1/04 ,  H04L7/00 ,  H04B1/38

Abstract: A device an method for detecting digital impairments affecting an upstream pulse code modulation (PCM) channel in a digital communication network (36), involves: receiving, by a digital PCM modem (38) interconnected to the digit al communication network (36), a random sequence of digital values selected fro m a constellation of digital values transmitted over the upstream PCM channel of the digital communication network (36); establishing distributions of the received digital values, each distribution corresponding to one of a plurali ty of time intervals; and deriving from the distributions the types of robbed b it signaling and digital loss affecting the upstream PCM channel of the digital communication network (36) for each time interval.

公开(公告)号：AU3473701A

公开(公告)日：2001-08-14

申请号：AU3473701

申请日：2001-02-01

Applicant: MOTOROLA INC

Inventor： PILOZZI JOHN ,  KIM DAE-YOUNG ,  MEHRABANZAD SEPEHR ,  LIU JACK ,  AHMED S ARIF ,  PARIZHSKY VLADIMIR

IPC: H04L7/00 ,  H04L25/49

Abstract: A system and method for adjusting the phase of the analog signal produced by an analog modem connected to a digital modem over a telephone network. The digital portion of the telephone network is locked to the network clock, and the modems have no control over the sampling timing or rate as the analog signal is sampled and quantized by a codec. If the analog signal is shifted in phase relative to the network clock, then the codec may be sampling at unresolvable points on the analog signal, thereby causing errors and a decrease in the usable bandwidth for transmitting data. The analog modem symbol frequency is locked to the clock of the digital network using loop-back timing. A phase estimate is computed using the quantized samples of a known reference signal. Next, a "phase offset" is calculated by comparing the phase estimate to an optimum phase value. Then the digital modem sends the calculated phase offset information to the analog modem. The analog modem then delays its transmitted signal by the phase offset. After the phase of the analog modem's transmitter is adjusted, the analog signal reaches the codec at the phase desired by the digital modem.

公开(公告)号：AU3324901A

公开(公告)日：2001-08-14

申请号：AU3324901

申请日：2001-02-01

Applicant: MOTOROLA INC

Inventor： KIM DAE-YOUNG ,  MEHRABANZAD SEPEHR ,  PILOZZI JOHN

IPC: H04L25/03 ,  H04B3/04 ,  H04B3/06 ,  H04B7/005 ,  H04L25/49 ,  H04B1/38 ,  H04B14/04 ,  H04B1/10 ,  H04B1/00

Abstract: A method and apparatus is provided for controlling the transmit power of an analog modem when the transmit power level does not match the desired transmit power level, thus conforming to FCC regulations on transmit power and/or eliminating non-linearities associated with higher than required power levels and loss of signal-to-noise ratio and concomitant at loss of data rate if the transmit power levels are less than that desired. In one embodiment, the power level at the analog modem is sensed to ascertain if it is not at the desired transmit power level, with adjustment being provided by transmitting the desired change in the transmit power level to the digital modem, whereupon mapping parameters are redefined by adjusting the number of equivalence classes, thus to adjust transmit power at analog modem.

公开(公告)号：AU3322401A

公开(公告)日：2001-08-14

申请号：AU3322401

申请日：2001-02-01

Applicant: MOTOROLA INC

Inventor： PILOZZI JOHN ,  KIM DAE-YOUNG ,  MEHRABANZAD SEPEHR ,  MAURER PATRICK ,  LIU JACK ,  AHMED S ARIF ,  PARIZHSKY VLADIMIR

IPC: H04J3/00 ,  H04B14/04 ,  H04J3/12 ,  H04L25/49 ,  H04M7/06 ,  H03M13/25 ,  H04L23/02

Abstract: A system and method for shifting the relative phases of a PCM data frame and a network RBS frame by one or more symbols is disclosed. The method includes determining whether or not RBS is present. If RBS is present, the slots affected by RBS are identified. Next it is determined what data slots, if any, are affected by encoding. The PCM data frame is shifted so the RBS constraint and the encoding constraint do not coincide at any particular data slot. For one particular PCM upstream modulation scheme, the digital modem adjusts the relative phases of the data-mode frame and network RBS frame such that a minimum number of trellis-modified symbols fall on network RBS affected slots. This information is transmitted to an analog modem. The amount of shift can be conveyed to an analog modem in the same data sequence used to send upstream constellation sets and mapping parameters during an initial training sequence. The present invention improves the performance of any PCM modem that employs a data frame structure in which not all symbols are subject to the same constraints, for example, due to trellis coding.