Radio access networks

Patent metadata

Field	Value
Publication number	US-9380466-B2
Application number	US-201313762284-A
Country	US
Kind code	B2
Filing date	Feb 7, 2013
Priority date	Feb 7, 2013
Publication date	Jun 28, 2016
Grant date	Jun 28, 2016

Abstract

Among other things, a communication system comprising remote units and a controller is described. The remote units exchange radio frequency (RF) signals with mobile devices. At least some of the RF signals comprise information destined for, or originating from, a mobile device. The controller comprises one or more modems and is connected to an external network. At least one of the modems is a baseband modem and is configured to pass first data corresponding to the information. The controller is separated from the remote units by an intermediate network over which second data corresponding to the information is carried in frames between the controller and the remote units. The second data comprises baseband data and at least some of the baseband data is compressed in a frequency domain. The remote units and the controller are configured to compress the baseband data for transmission over the intermediate network.

First claim

What is claimed is:

1. A communication system comprising:
remote units to exchange radio frequency (RF) signals with mobile devices, at least some of the RF signals comprising information destined for, or originating from, a mobile device among the mobile devices; and
a controller comprising one or more modems and connected to an external network, at least one of the modems being a baseband modem and being configured to pass first data corresponding to the information;
wherein the controller is separated from the remote units by an intermediate network over which second data corresponding to the information is carried in frames between the controller and the remote units, wherein the network comprises a switched Ethernet network,
wherein the second data comprises baseband data, and at least some of the baseband data is compressed in a frequency domain, and
wherein the remote units and the controller are configured to compress the baseband data for transmission over the intermediate network.

2. The communication system of claim 1 , wherein a rate of transmission of the baseband data over the intermediate network is at most 1 Gb/s.

3. The communication system of claim 1 , wherein the baseband data is represented by complex-valued signals having real and imaginary components, and the controller is configured to compress the baseband data by quantizing the complex-valued signals in the frequency domain to produce quantized baseband data, and to transmit binary data representative of the quantized baseband data to the remote units.

4. The communication system of claim 3 , wherein the remote units are configured to reconstruct the quantized baseband data upon receipt of the compressed baseband data.

5. The communication system of claim 4 , wherein the remote units are configured to apply an inverse fast Fourier transform on the reconstructed baseband data.

6. The communication system of claim 3 , wherein the controller is configured to quantize the baseband data in the frequency domain using a quantizer having a fixed rate and a fixed step size.

7. The communication system of claim 6 , wherein the controller is configured to quantize independently the real and imaginary components of the baseband data in the frequency domain.

8. The communication system of claim 6 , wherein the controller is configured to send information about the fixed rate and the fixed step size to the remote units when the remote units and the controller are connected.

9. The communication system of claim 3 , wherein the controller is configured to quantize the baseband data in the frequency domain using a quantizer having a fixed rate and an adjustable step size.

10. The communication system of claim 9 , wherein the controller is configured to send side information about the fixed rate and a step size to a remote unit once per subframe, the remote unit being among the remote units.

11. The communication system of claim 3 , wherein the controller is configured to quantize the baseband data in the frequency domain using a quantizer having a rate and a step size, the rate and the step size both being adjustable.

12. The communication system of claim 11 wherein the controller is configured to adjust the step size according to energy of the quantized baseband data.

13. The communication system of claim 11 , wherein the controller is configured to adjust the rate according to a modulation and coding scheme of the baseband data.

14. The communication system of claim 11 , wherein the RF signals are compatible with the long term evolution (LTE) standard.

15. The communication system of claim 14 , wherein the controller is configured to send side information about the rate of the quantizer to a remote unit for each of plural resource element groups (REG) and physical resource blocks (PRB) in each orthogonal frequency-division multiplexing (OFDM) symbol of a subframe, the remote unit being among the remote units.

16. The communication system of claim 14 , wherein the controller is configured to compress the baseband data by not sending to the remote units any data for unused resource element groups (REGs) or physical resource blocks (PRBs) in each orthogonal frequency-division multiplexing (OFDM) symbol of the baseband data.

17. The communication system of claim 1 , wherein the baseband data in the frequency domain belongs to, or is derived from, a discrete-amplitude signal constellation, and wherein the controller is configured to compress the baseband data without quantization by sending binary data representing the discrete-amplitude signals to the remote units.

18. The communication system of claim 17 , wherein the discrete-amplitude signal constellation comprises a quadrature amplitude modulation (QAM) signal constellation.

19. The communication system of claim 17 , wherein the RF signals carry orthogonal frequency-division multiplexing (OFDM) symbols, and the controller is configured to send the binary data to the remote units in the same order as the corresponding OFDM symbols are to be transmitted by the remote units over the air to the mobile devices.

20. The communication system of claim 1 , wherein the remote units are configured to compress the baseband data by quantizing the baseband data in the frequency domain to produce quantized baseband data, and to transmit binary data representative of the quantized baseband data to the controller, the remote unit being among the remote units.

21. The communication system of claim 20 , wherein a remote unit is configured to receive data in time domain from the mobile device and to apply a fast Fourier transform to the data in the time domain to produce the baseband data in the frequency domain, the remote unit being among the remote units.

22. The communication system of claim 20 , wherein a remote unit is configured to quantize the baseband data in the frequency domain using a quantizer having a fixed rate and a fixed step size, the remote unit being among the remote units.

23. The communication system of claim 20 , wherein a remote unit is configured to quantize the baseband data in the frequency domain using a quantizer having a fixed rate and an adjustable step size, the remote unit being among the remote units.

24. The communication system of claim 23 , wherein the frames of the baseband data comprise orthogonal frequency-division multiplexing (OFDM) symbols and the remote unit is configured to select a step size based on an average energy of the quantized baseband data.

25. The communication system of claim 24 , wherein the average energy is an average of energies of baseband data that belong to a long term evolution (LTE) channel.

26. The communication system of claim 23 , wherein the remote unit is configured to select a step size based on a distribution of the baseband data in the frequency domain.

27. The communication system of claim 23 , wherein the remote unit is configured to send side information about the quantizer to the controller for the controller to reconstruct the received quantized baseband data.

28. The communication system of claim 20 , wherein a remote unit is configured to quantize the baseband data in the frequency domain using a quantizer having a rate and a step size, the rate and the step size both being adjustable, the remote unit being among the remote units.

29. The communication system of claim 28 , whe

Assignees

• Airvana Lp
• Commscope Technologies Llc

Inventors

• Eyuboglu Vedat
• Barabell Arthur J

Classifications

• H04W72/23

  in the downlink direction of a wireless link, i.e. towards a terminal · CPC title

• H04W72/21

  in the uplink direction of a wireless link, i.e. towards the network · CPC title

• H04W72/54

  based on quality criteria · CPC title

• H04B7/04

  using two or more spaced independent antennas · CPC title

• H04W74/0833

  Random access procedures, e.g. with 4-step access · CPC title