Methods, decoder and encoder for handling a data stream for transmission between a remote unit and a base unit of a base station system

Patent metadata

Field	Value
Publication number	US-11329668-B2
Application number	US-201716954963-A
Country	US
Kind code	B2
Filing date	Dec 20, 2017
Priority date	Dec 20, 2017
Publication date	May 10, 2022
Grant date	May 10, 2022

Abstract

A method performed by an encoder of a base station system, for handling a data stream for transmission over a transmission connection between a remote unit and a base unit of the base station system, the remote unit being arranged to transmit wireless signals to, and receive from, mobile stations. The method comprises quantizing a plurality of IQ samples, converting the quantized plurality of IQ samples to IQ predictions, calculating per sample a difference between the quantized plurality of IQ samples and the IQ predictions in order to create IQ prediction errors. The method further comprises quantizing the IQ predictions or the IQ prediction errors, entropy encoding the IQ prediction errors and sending the entropy encoded IQ prediction errors over the transmission connection to a decoder of the base station system. The method can be performed by a decoder.

First claim

The invention claimed is:

1. A method performed by an encoder of a base station system of a wireless communication network, for handling a data stream for transmission over a transmission connection between a remote unit and a base unit of the base station system, the remote unit being arranged to transmit wireless signals to, and receive from, mobile stations, the data stream comprising a plurality of IQ samples comprising a first IQ sample and a second IQ sample, the method comprising:
quantizing the plurality of IQ samples by a first quantizer;
converting, by an encoder predictor, the quantized plurality of IQ samples to predictions of the plurality of IQ samples, the predictions comprising a prediction of the first IQ sample and a prediction of the second IQ sample;
calculating on a per IQ sample level, a difference between the quantized plurality of IQ samples and the predictions of the plurality of IQ samples, so that a difference between a quantized first IQ sample and the prediction of the first IQ sample, and a difference between a quantized second IQ sample and the prediction of the second IQ sample are calculated, in order to create a plurality of IQ prediction errors;
quantizing the predictions of the plurality of IQ samples before the calculating, or quantizing the plurality of IQ prediction errors after the calculating, by a second quantizer;
encoding, after the quantizing by the second quantizer, the plurality of IQ prediction errors with fewer bits than a number of bits of the plurality of IQ prediction errors, and
sending the encoded plurality of IQ prediction errors over the transmission connection to a decoder of the base station system.

2. The method according to claim 1 , wherein the first quantizer and the second quantizer have the same number of quantization levels.

3. The method according to claim 1 , wherein the first quantizer and the second quantizer have the same quantization step size.

4. The method according to claim 1 , wherein when any of the IQ prediction errors is outside a predetermined range, reducing the any IQ prediction error until the any IQ prediction error is within the predetermined range.

5. The method according to claim 4 , wherein the reducing comprises reducing the any IQ prediction error to modulo M, where M is a number of quantization levels of the first quantizer, which number of quantization levels is related to the predetermined range.

6. The method according to claim 1 , further comprising, when transmission of a new packet of the data stream is to begin, resetting a filter state of the encoder predictor to a predetermined state.

7. The method according to claim 1 , further comprising, in the first quantizer and in the second quantizer, the quantizing is performed by quantizing the first IQ sample to a basic value added with a first IQ-sample specific value, and quantizing the second IQ sample to the basic value added with a second IQ-sample specific value.

8. The method according to claim 7 , further comprising sending the basic value of the first quantizer over the transmission connection to the decoder.

9. The method according to claim 1 , further comprising:
de-quantizing the quantized plurality of IQ samples, quantized by the first quantizer, and wherein the converting is performed on the de-quantized quantized plurality of IQ samples.

10. A method performed by a decoder of a base station system of a wireless communication network, for handling a data stream received over a transmission connection between a remote unit and a base unit of the base station system, the remote unit being arranged to transmit wireless signals to, and receive from, mobile stations, the data stream comprising a plurality of IQ samples comprising a first IQ sample and a second IQ sample, the method comprising:
receiving, from an encoder of the base station system over the transmission connection, a plurality of encoded IQ prediction errors of the IQ samples of the data stream, comprising a first IQ prediction error and a second IQ prediction error;
decoding the received plurality of encoded IQ prediction errors into more bits than a number of bits of the plurality of encoded IQ prediction errors;
converting, in a feed-back loop by a decoder predictor, an output data stream of the decoder comprising the plurality of IQ samples, to predictions of the plurality of IQ samples comprising a prediction of the first IQ sample and a prediction of the second IQ sample;
adding the predictions of the plurality of IQ samples to the decoded plurality of IQ prediction errors on a per IQ sample level so that the prediction of the first IQ sample is added to a decoded first IQ prediction error and the prediction of the second IQ sample is added to a decoded second IQ prediction error, in order to create the plurality of IQ samples, and
quantizing, by a decoder quantizer, the predictions of the plurality of IQ samples before the adding, or quantizing the plurality of IQ samples after the adding.

11. The method according to claim 10 , wherein the quantizing comprises quantizing the predictions of the plurality of IQ samples or quantizing the plurality of IQ samples using a same number of quantization levels and quantization step size as used at a quantization performed by the encoder.

12. The method according to claim 10 , wherein when any of the plurality of quantized IQ samples is outside a predetermined range, reducing the any of the plurality of IQ samples until the any quantized IQ sample is within the predetermined range.

13. The method according to claim 12 , wherein the reducing comprises reducing the any of the plurality of IQ prediction errors to modulo M, where M is a number of quantization levels of the decoder quantizer, which number of quantization levels is related to the predetermined range.

14. The method according to claim 10 , when receiving information from the encoder that transmission of a new packet is to begin, resetting a filter state of the decoder predictor to a predetermined state.

15. The method according to claim 10 , wherein the quantizing is performed by quantizing the prediction of the first IQ sample or the first IQ sample to a basic value added with a first IQ-sample specific value, and quantizing the prediction of the second IQ sample or the second IQ sample to the basic value added with a second IQ-sample specific value.

16. The method according to claim 10 , further comprising:
de-quantizing the plurality of IQ samples.

17. A non-transitory computer-readable storage medium comprising instructions which, when executed by at least one processing circuitry of an encoder of a base station system for handling a data stream for transmission over a transmission connection between a remote unit and a base unit of the base station system, the data stream comprising a plurality of IQ samples comprising a first IQ sample and a second IQ sample, are capable of causing the encoder to perform operations comprising:
quantizing the plurality of IQ samples by a first quantizer;
converting, by an encoder predictor, the quantized plurality of IQ samples to predictions of the plurality of IQ samples, the predictions comprising a prediction of the first IQ sample and a prediction of the second IQ sample;
calculating, on a per IQ sample level, a difference between the quantized plurality of IQ samples and the predictions of the plurality of IQ samples, so that a difference between a quantized first IQ sample and the prediction of the first IQ sample, and a difference between a quantized second IQ sample and the prediction of the second IQ samp

Assignees

• Ericsson Telefon Ab L M

Inventors

• Berg Miguel
• Lu Chenguang
• Börjesson Per Ola
• Cederholm Daniel
• Trojer Elmar

Classifications

• Y02D30/70

  in wireless communication networks · CPC title

• H03M7/6041 Primary

  Compression optimized for errors · CPC title

• H04L25/4927

  using levels matched to the quantisation levels of the channel · CPC title

• H04L1/0014

  by adapting the source coding · CPC title

• H03M7/30

  Compression (speech analysis-synthesis for redundancy reduction G10L19/00; for image communication H04N); Expansion; Suppression of unnecessary data, e.g. redundancy reduction · CPC title