Crest Factor Reduction IP

Optimized for HetNet small cells and low power radios

Crest factor reduction (CFR) selectively reduces the peak-to-average ratio (PAR) of wideband digital signals, such as those used in third-generation (3G) code division multiple access (CDMA) or long term evolution (LTE) wireless applications.

CFR Diagram

The Lattice peak cancellation crest factor reduction (PC-CFR) IP core is part of the digital front end (DFE) suite of IP cores optimized for HetNet applications. The core is highly programmable and can be customized to achieve the desired resource vs performance trade off. The core is optimized for use with ECP3 FPGA family and achieves up to 4dB of PAR reduction for LTE signals.

Features

  • The Lattice PC-CFR IP supports between 1 to 4 antennas
  • The core can be configured for clock-to-sample ratios of 1, 2 or 4
  • Provides 1, 2 or 3 sequential detection and cancellation stages to remove peaks
  • Cancellation pulses may be real or complex
  • Pulse coefficients can be pre-configured at generation time through coefficient file or configured during operation through the Wishbone interface
  • Each filter stage can be independently configured with detection target peak threshold and cancellation pulse coefficients
  • Number of clip engines for each filter stage can be independently configured
  • The maximum cancellation pulse length is configurable.
  • The IP provides parallel or TDM (Time-Division Multiplexing) quadrature (I & Q) format for input/output mode
  • Configurable data width
  • Configurable coefficient width
  • Option for input/output gain

Block Diagram

Performance and Size

ECP51
User-Configurable Mode Data Width Coefficient Width Highspeed Mode Registers LUT4s Slices EBR MULT 18x18 fMAX (MHz)
1 Antenna, 1 Stage, 8 Clip engines 18 18 true 2988 2704 2193 5 10 223
1 Antenna, 2 Stage, 10 Clip engines 18 18 true 4672 4537 3535 7 14 223
1 Antenna, 3 Stage, 14 Clip engines 18 18 true 6800 6658 5166 10 20 223

1. Performance and utilization data are generated targeting a LFE5UM-85F-8MG756C device using Lattice Diamond 3.2 and Synplify Pro I- 2013.09L software. Performance may vary when using a different software version or targeting a different device density or speed grade within the ECP5 family.

LatticeECP31
User-Configurable Mode Data Width Coefficient Width Highspeed Mode Registers LUT4s Slices EBR MULT 18x18 fMAX (MHz)
1 Antenna, 1 Stage, 8 Clip engines 18 18 false 2750 2643 2029 5 18 259
1 Antenna, 2 Stage, 10 Clip engines 18 18 false 4321 4493 3313 7 24 263
1 Antenna, 3 Stage, 14 Clip engines 18 18 false 6338 6599 4870 10 34 266

1. Performance and utilization data are generated targeting a LFE3-70EA-9FN672C device using Lattice Diamond 3.2 and Synplify Pro I- 2013.09L software. Performance may vary when using a different software version or targeting a different device density or speed grade within the LatticeECP3 family.

Documentation

Quick Reference
TITLE NUMBER VERSION DATE FORMAT SIZE
CFR IP User Guide
IPUG109 1.1 6/1/2014 PDF 3.8 MB
DFE Demo User's Guide
UG68 1.0 9/1/2013 PDF 2.2 MB