Systems and methods for multiband delta sigma digitization

1. A digital network, comprising:

a central processing unit including a digitization interface configured to (i) digitize, using delta-sigma digitization, at least one wireless service for at least one radio access technology (RAT) into a delta-sigma digitized wireless service, and (ii) implement a noise transfer function corresponding to a signal band of the at least one wireless service;

a digital transport medium (i) in operable communication with the central processing unit, and (ii) configured to transmit the delta-sigma digitized wireless service from the central processing unit; and

a radio receiver disposed remotely from the central processing unit and including a filter corresponding to the noise transfer function of the digitization interface, the radio receiver configured to (i) operably receive the delta-sigma digitized wireless service from the central processing unit over the digital transport medium, (ii) filter the received delta-sigma digitized wireless service into a filtered digital signal, and (iii) convert the filtered digital signal into an analog radio frequency (RF) signal.

2. The network of claim 1 , wherein the digitization interface comprises a multiband delta-sigma analog-to-digital converter (ADC).

3. The network of claim 2 , wherein the central processing unit comprises a baseband processing unit (BBU) and the radio receiver comprises a remote radio head (RRH).

4. The network of claim 3 , wherein the digitization interface comprises a baseband processor, an RF up-converter, and a frequency domain multiplexer (FDM).

5. The network of claim 1 , wherein the digital transport medium comprises an optical fiber.

6. The network of claim 5 , wherein the digitization interface further comprises an electrical-to-optical interface at the optical fiber, and wherein the multiband delta-sigma ADC is disposed between the electrical-to-optical interface and the FDM.

7. The network of claim 6 , wherein the digitization interface further comprises a wavelength division multiplexing multiplexer disposed between the electrical-to-optical interface and the multiband delta-sigma ADC, and wherein the wavelength division multiplexing multiplexer is configured to receive the delta-sigma digitized wireless service from the BBU and at least one different digitized wireless service from a different BBU.

8. The network of claim 1 , wherein the central processing unit comprises a central unit and a distributed unit, and the radio receiver comprises a radio unit.

9. The network of claim 1 , wherein the filter comprises at least one of a passive filter, an active filter, and a programmable filter.

10. The network of claim 1 , further comprising at least one of a WiMAX, a Wi-Fi, a WiGig, a 3GPP, a 4G, a 5G, and a 5G-NR radio access technology (RAT) network.

11. A method for performing delta-sigma digitization of an aggregated signal, the aggregated signal including a plurality of different signal bands from a communication network, the method comprising the steps of:

oversampling the aggregated signal at rate equal to an oversampling rate times the Nyquist sampling rate, to generate an oversampled signal and quantization noise;

noise shaping the oversampled signal to implement a noise transfer function (NTF) and push the quantization noise into out-of-band frequency spectra corresponding to respective spectral portions between the plurality of different signal bands;

transmitting the noise shaped signal over a digital transport medium; and

filtering the transmitted noise shaped signal, received from the digital transport medium, using a filter corresponding to the NTF to remove the out-of-band quantization noise from the plurality of different signal bands.

12. The method of claim 11 , wherein the step of oversampling comprises a substep of quantizing the aggregated signal.

13. The method of claim 12 , wherein the substep of quantizing comprises one-bit quantization utilizing a binary signal.

14. The method of claim 12 , wherein the substep of quantizing comprises two-bit quantization utilizing four-level pulse amplitude modulation.

15. The method of claim 11 , wherein the plurality of different signal bands are contiguous.

16. The method of claim 15 , wherein the plurality of different signal bands comprise at least one of a long term evolution (LTE) carrier aggregation and a Wi-Fi channel bonding.

17. The method of claim 11 , wherein the plurality of different signal bands are non-contiguous.

18. The method of claim 11 , wherein the plurality of different signal bands originate from a same wireless radio access technology.

19. The method of claim 11 , wherein the plurality of different signal bands originate from different wireless radio access technologies.

20. The method of claim 11 , wherein the NTF corresponds to a null point of the quantization noise.