WHITE PAPER
COTS Software Defined Radio for 5G Development
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Theory Side-Bar: Maximum Data Transport Requirements
Example 1
A remote RRH with two antennas and a 5MHz LTE channel
BW will have the following data transfer requirements:
a. The 5MHz channel requires at least 10MHz sampling,
or 10 MSPS to capture the information. There are two
bytes per 16-bit sample, and two samples for I&Q.
b. SRmax = 10 MS/s x 2 bytes/S x 2 for I&Q = 40Mbytes/s
x 8 bits/byte = 320 Mb/s per antenna
c. Two antenna inputs = 320 Mb/s x 2 = 640 Mb/s
of data throughput and no issue for a CPRI
port with a 10 to 25 Gb/s capacity
Example 2
A new 5G link with a 100MHz channel and 8 antenna
inputs increases the data transfer requirement
to ≈ 52 Gb/s requiring multiple CPRI ports.
(Calculations ignore encoding variations).
SOFTWARE
Depending upon the desired level of control, either BSP
routines need to be created for the new IP and ARM
processors, or the ARM processors in conjunction with the
FPGA can be programmed to operate autonomously.
CONCLUSION
The purpose of this article was to familiarize a traditional radio
engineer about the latest hardware, firmware, software, and
design tools available from COTS vendors to create an SDR
system that can be used for a 5G development platform. These
SDR platforms provide superior signal integrity performance,
high test repeatability and modular assemblies that adjust
to constantly changing 5G design requirements. Future 5G
implementations will require many development platforms
for experimentation and the use of a COTS system as a
starting point will ensure an accelerated time-to-market.
