Systems and methods for delta-sigma digitization

Patent metadata

Field	Value
Publication number	US-10652056-B2
Application number	US-201916391061-A
Country	US
Kind code	B2
Filing date	Apr 22, 2019
Priority date	Nov 14, 2017
Publication date	May 12, 2020
Grant date	May 12, 2020

Abstract

A baseband processing unit includes a baseband processor configured to receive a plurality of component carriers of a radio access technology wireless service, and a delta-sigma digitization interface configured to digitize at least one carrier signal of the plurality of component carriers into a digitized bit stream, for transport over a transport medium, by (i) oversampling the at least one carrier signal, (ii) quantizing the oversampled carrier signal into the digitized bit stream using two or fewer quantization bits.

First claim

What is claimed is:

1. A delta-sigma digitization interface for digitizing an input analog signal into a digitized bit stream, comprising:
a sampling unit configured to sample the input analog signal at a predetermined sampling rate to produce a sampled analog signal;
a segmentation unit configured to segment the sampled analog signal into a plurality of separate data pipelines;
a delta-sigma analog-to-digital converter (ADC) configured to individually quantize a respective signal segment contained within each of the plurality of data pipelines into a digitized bit stream segment according to a predetermined number of quantization bits;
a cascading unit configured to combine the respective quantized signal segments into a single digitized output stream; and
an output port for transmitting the single digitized output stream to a transport medium as the digitized bit stream,
wherein the predetermined number of quantization bits is one, and
wherein the delta-sigma ADC is further configured to perform one-bit quantization according to a binary quantization protocol.

2. The interface of claim 1 , wherein the delta-sigma ADC comprises a field programmable gate array (FPGA).

3. The interface of claim 1 , wherein the binary quantization protocol comprises on-off keying.

4. The interface of claim 2 , wherein the sampling unit comprises an FPGA mezzanine card (FMC).

5. The interface of claim 4 , wherein the FMC is configured to sample the input analog signal at 5 GSa/s.

6. A delta-sigma digitization interface for digitizing an input analog signal into a digitized bit stream, comprising:
a sampling unit configured to sample the input analog signal at a predetermined sampling rate to produce a sampled analog signal;
a segmentation unit configured to segment the sampled analog signal into a plurality of separate data pipelines;
a delta-sigma analog-to-digital converter (ADC) configured to individually quantize a respective signal segment contained within each of the plurality of data pipelines into a digitized bit stream segment according to a predetermined number of quantization bits;
a cascading unit configured to combine the respective quantized signal segments into a single digitized output stream;
an output port for transmitting the single digitized output stream to a transport medium as the digitized bit stream; and
an input buffer logically disposed between the segmentation unit and the delta-sigma ADC,
wherein the input buffer is configured to distribute contiguous data portions of the sampled analog signal in sequential order to respective ones of the plurality of data pipelines.

7. The interface of claim 6 , wherein the input buffer comprises an input first-in-first-out unit (FIFO) for each of the plurality of data pipelines.

8. The interface of claim 7 , wherein the input FIFO utilizes at least 10-bits to store each sample of the sampled analog signal in the input buffer.

9. The interface of claim 8 , wherein the input FIFO is configured to store W samples, where W represents a positive integer, wherein the input FIFO has a size of at least 10 W bits, and wherein each of the W samples is stored in a 10-bit buffer.

10. The interface of claim 6 , further comprising an output buffer including a separate output first-in-first-out unit (FIFO) for each of the plurality of data pipelines.

11. The interface of claim 10 , wherein the output FIFO utilizes at least 1-bit to store segments of the sampled analog signal in the output buffer.

12. The interface of claim 11 , further comprising an input FIFO, wherein a size of the output FIFO is one tenth of the size of the input FIFO.

13. The interface of claim 2 , wherein a clock rate of the FPGA for each of the plurality of data pipelines is approximately 156.25 MHz or less.

14. The interface of claim 2 , wherein the FPGA is disposed within a distributed unit (DU) of a communication network.

15. The interface of claim 1 , wherein the input analog signal comprises at least one of a 5G new radio (5GNR) signal and a long term evolution (LTE) signal.

16. A method of optimizing a delta-sigma analog-to-digital converter (ADC) architecture for a field programmable gate array (FPGA), comprising the steps of:
simulating a performance of the delta-sigma ADC according to a first floating-point calculation using floating-point coefficients of the delta-sigma ADC;
approximating key coefficients from a floating-point format to a fixed-point format;
performing a second floating-point calculation of the delta-sigma ADC performance using the approximated key fixed-point coefficients;
performing a first fixed-point calculation of the delta-sigma ADC performance for a continuous input data stream using fixed-point coefficients obtained from performance of the second floating-point calculation;
performing a second fixed-point calculation of the delta-sigma ADC performance, wherein the continuous input data stream is segmented into a plurality of separate data blocks, and wherein the second fixed-point calculation is individually performed on each separate segmented data block; and
evaluating performance of the FPGA having a logical structure based on the performance of the second fixed-point calculation individually performed on each of the plurality of separate data blocks.

17. The method of claim 16 , wherein the steps of performing the first and second fixed-point calculations are individually repeated until a calculated degradation of the delta-sigma ADC performance is within a predetermined acceptable value.

18. The method of claim 16 , wherein the logical structure comprises a pipeline architecture, and further comprising, after the step of evaluating, a step of determining whether the operational speed of each pipeline in the pipeline architecture meets an operational speed time constraint of the FPGA.

19. The interface of claim 1 , wherein the delta-sigma ADC comprises a processor and a memory, and wherein the memory contains computer-executable instructions that, when executed by the processor, cause the delta-sigma ADC to implement a delta-sigma algorithm.

20. The interface of claim 1 , wherein the delta-sigma ADC comprises an application specific integrated circuit (ASIC) configured to implement a delta- sigma algorithm.

Assignees

• Cable Television Laboratories Inc

Inventors

• Wang Jing
• Campos Luis Alberto
• Jia Zhensheng

Classifications

• H04Q11/00

  Selecting arrangements for multiplex systems (multiplex systems H04J) · CPC title

• H04W88/085

  Access point devices with remote components · CPC title

• H03M3/45

  with distributed feedforward inputs, i.e. with forward paths from the modulator input to more than one filter stage · CPC title

• H03M3/496

  Details of sampling arrangements or methods · CPC title

• H03M3/402

  Arrangements specific to bandpass modulators · CPC title