PCM upstream data transmission server
AssigneeTexas Instruments Incorporated
InventorCory Samuel Modlin
Life of this patent
Estimating the term…
Abstract
A method for designing an equalizer and tracking performance for upstream PCM in a digital communications network is described. The invention optimizes upstream data rate rates for data transmissions in a network between a client modem a server modem. During training, the upstream channel impulse response is identified compensating for any robbed bit signalling. The upstream transmit equalizer is computed in closed form based on the identified channel. An equalizer in the receiver is also used to track timing and channel variations. The invention approximates bit error rate performance by looking for code violations in the trellis code decoder and tracking their frequency. The bit error rate is used to determine if the current modem parameters need to be re-designed.
Claims19
A method for pulse code modulation upstream data transmissions in a network between a client modem and a server modem, comprising:
- performing channel identification;
- and
- calculating the client modem transmit upstream equalizer in closed form using a decision-feedback filter solution that jointly optimizes the amount of intersymbol interference and the transmit power.
A method for assessing the bit error rate performance in a network between a client modem and a server modem, comprising:
- approximating the bit error rate by observing discrepancies in the trace-back path in the Viterbi decoder as the current sample time is updated.
A method for pulse code modulation upstream data transmissions in a network between a client modem and a server modem, comprising:
- compensating for timing drift in a client modem transmitter and small channel variations using a receiver data mode equalizer in said server modem.
A method for pulse code modulation upstream data transmissions in a network between a client modem a server modem, comprising:
- performing channel identification;
- equalizing said transmissions using a closed form upstream data mode equalizer in said client modem based on said channel identification;
- detecting errors in said transmissions with an trellis code decoder;
- using a receiver data mode equalizer to compensate for timing drift and channel variations in said client modem transmitter.
The method of 18, wherein:
- said receiver equalizer uses a filter to compensate for timing drift of said client transmitter and small variations in the channel.
Dependencies are inferred from the claim text.