Systems and methods for a fronthaul network
Various embodiments provide for systems, methods, or apparatuses that provide a fronthaul architecture that facilitates high fidelity and low latency communication between a radio processing unit, such as a baseband unit (BBU), which may be located a central office (CO), and a remote transceiver, which may comprise a remote radio head (RRH) or a remote radio unit (RRU), which may be located at remote cell site.
1. A method comprising:
receiving at a remote station a first radio frequency signal from a prior station, the remote station including a radio transmitter operating at a radio transmitter frequency, the first radio frequency signal being at a first radio frequency, the prior station having added prior analog pre-distortion to a prior radio frequency signal, the prior radio frequency signal having a prior radio frequency, the first radio frequency signal being based on the prior radio frequency signal, the prior radio frequency being at or near the radio transmitter frequency of the radio transmitter at the remote station;
downconverting a first intermediate signal to a second radio frequency signal at the radio transmitter frequency, the first intermediate signal being based on the first radio frequency signal and being at the first radio frequency;
adding analog pre-distortion on a second intermediate signal based on a first control signal to produce a first pre-distorted radio frequency signal at the radio transmitter frequency, the second intermediate signal being based on the second radio frequency signal;
amplifying a third intermediate signal to a first amplified radio frequency signal at the radio transmitter frequency, the third intermediate signal being based on the first pre-distorted radio frequency signal, the first control signal being based on the first amplified radio frequency signal; and
transmitting by the radio transmitter a fourth intermediate signal, the fourth intermediate signal being based on the first amplified radio frequency signal and being at the radio transmitter frequency.
2. The method of claim 1 , wherein the radio transmitter comprises a remote radio head (RRH).
3. The method of claim 1 , wherein the first radio frequency comprises a microwave or millimeter wave frequency.
4. The method of claim 1 , wherein the radio transmitter frequency relates to cellular communications.
5. The method of claim 1 , wherein the radio transmitter frequency includes a Long-Term Evolution (LTE) frequency.
6. The method of claim 1 , wherein the first radio frequency signal is received from a central fronthaul module.
7. The method of claim 1 , wherein the first radio frequency signal is generated by a process of:
receiving, at a central fronthaul module, a backhaul baseband signal comprising data from a baseband unit, the backhaul baseband signal being received over a wired Common Public Radio Interface (CPRI) interconnection coupling the central fronthaul module to the baseband unit;
converting the backhaul baseband signal to the prior radio frequency signal having the prior radio frequency;
pre-distorting, using an analog pre-distorter, a fifth intermediate signal to produce a second pre-distorted radio frequency signal, the fifth intermediate signal being based on the prior radio frequency signal and being at the prior radio frequency;
upconverting a sixth intermediate signal to a fourth radio frequency signal at the first radio frequency, the sixth intermediate signal being based on the second pre-distorted radio frequency signal;
amplifying a seventh intermediate signal to a second amplified radio frequency signal having the first radio frequency, the seventh intermediate signal being based on the fourth radio frequency signal; and
transmitting the first radio frequency signal, the first radio frequency signal being based on the second amplified radio frequency signal.
8. A system on a remote station, the system comprising:
a radio transmitter operating at a radio transmitter frequency;
a receiver module configured to receive a first radio frequency signal from a prior station, the first radio frequency signal being at a first radio frequency, the prior station having added prior analog pre-distortion to a prior radio frequency signal, the prior radio frequency signal having a prior radio frequency, the first radio frequency signal being based on the prior radio frequency signal, the prior radio frequency being at or near the radio transmitter frequency of the radio transmitter at the remote station;
a downconversion module configured to downconvert a first intermediate signal to a second radio frequency signal at a second radio frequency, the first intermediate signal being based on the first radio frequency signal and being at the first radio frequency;
a pre-distortion module configured to add analog pre-distortion on a second intermediate signal based on a first control signal to produce a first pre-distorted radio frequency signal at the radio transmitter frequency, the second intermediate signal being based on the second radio frequency signal;
a power amplifier configured to amplify a third intermediate signal to a first amplified radio frequency signal at the radio transmitter frequency, the third intermediate signal being based on the first pre-distorted radio frequency signal, the first control signal being based on the first amplified radio frequency signal; and
a transmission module configured to transmit by the radio transmitter a fourth intermediate signal, the fourth intermediate signal being based on the first amplified radio frequency signal and being at the radio transmitter frequency.
9. The system of claim 8 , wherein the radio transmitter comprises a remote radio head (RRH).
10. The system of claim 8 , wherein the first radio frequency comprises a microwave or millimeter wave frequency.
11. The system of claim 8 , wherein the radio transmitter frequency relates to cellular communications.
12. The system of claim 8 , wherein the radio transmitter frequency includes a Long-Term Evolution (LTE) frequency.
13. The system of claim 8 , wherein the receiver module receives the first radio frequency signal from a central fronthaul module.
14. The system of claim 8 , wherein the first radio frequency signal is generated by a process of:
receiving, at a central fronthaul module, a backhaul baseband signal comprising data from a baseband unit, the backhaul baseband signal being received over a wired Common Public Radio Interface (CPRI) interconnection coupling the central fronthaul module to the baseband unit;
converting the backhaul baseband signal to the prior radio frequency signal having the prior radio frequency;
pre-distorting, using an analog pre-distorter, a fifth intermediate signal based on a second control signal to produce a second pre-distorted radio frequency signal, the fifth intermediate signal being based on the prior radio frequency signal and being at the prior radio frequency;
upconverting a sixth intermediate signal to a fourth radio frequency signal at the first radio frequency, the sixth intermediate signal being based on the second pre-distorted radio frequency signal;
amplifying a seventh intermediate signal to a second amplified radio frequency signal having the first radio frequency, the seventh intermediate signal being based on the fourth radio frequency signal, the second control signal being based on the second amplified radio frequency signal; and
transmitting the first radio frequency signal, the first radio frequency signal being based on the second amplified radio frequency signal.
15. The system of claim 8 , wherein the first radio frequency signal is generated by a central fronthaul module comprising:
a conversion module configured to:
receive a backhaul baseband signal comprising data from a baseband unit, the backhaul baseband signal being received over a wired Common Public Radio Interface (CPRI) interconnection coupling the central fronthaul module to the baseband unit; and
convert the backhaul baseband signal to the prior radio frequency signal having the prior radio frequency;
an analog pre-distortion module configured to pre-distort a fifth intermediate signal based on a second control signal to produce a second pre-distorted radio frequency signal, the fifth intermediate signal being based on the prior radio frequency signal and being at the prior radio frequency;
an upconversion module configured to upconvert a sixth intermediate signal to a fourth radio frequency signal at the first radio frequency, the sixth intermediate signal being based on the second pre-distorted radio frequency signal;
a power amplifier configured to amplify a seventh intermediate signal to a second amplified radio frequency signal having the first radio frequency, the seventh intermediate signal being based on the fourth radio frequency signal, the second control signal being based on the first amplified radio frequency signal; and
a transmission module configured to transmit the first radio frequency signal, the first radio frequency signal being based on the second amplified radio frequency signal.