# Presentation: 045759

## A Flexible Low Cost EMWIN-LRIT Receiver for the GOES-R Transition

**A Flexible Low Cost EMWIN-LRIT Receiver for the GOES-R Transition**

- Dr. Jeremy Roberson
- Dr. Esteban Vallés
- Mr. Kevin King
- Mr. Konstantin Tarasov
- Dr. Eugene Grayver

**Miami, FL****December 8-12. 2008**

## Overview

**Purpose**: To design a radio platform to ease the transition to GOES-R
**Approach**: Move as much processing from hardware to software
**Advantages: **
- Lower Cost and More Generic Hardware
- Smaller Form Factor
- Greater Flexibility
- Upgradeability
**Challenges**: High data rates
- GOES-R HRIT/EMWIN: 927 kb/s
**Final Product**
- Small hardware board < $100 in parts
- Software Radio Package with throughput of > 1.4 Mbps

## System Diagram

**LNB**

**S/W Receiver**
**+**
**Imager**

- 136 Mhz
-       –
- 140 Mhz

**1 meter dish **
**G/T= -0.3 dB/K**** **

**USB**

**“****The Aerospace Corporation’s IF Digitizer (AID)**

- PC

**IF**

## Software Radio: Leveraging Emerging Technology

- General Purpose Computing
- Multiple Core processors
- Cheaper, Faster, Smaller
- Software Radio Algorithms
- GNU Radio Open Source Frame Work
- COTS IF Digitizers
- Ettus Research’s Universal Software Radio Peripheral
- $400 - $700

## Software Receiver: Block Diagram

**Software Receiver: Block Diagram**

- Physical Layer

- Data Link Layer

- Derandomization

- Reed Solomon

- Demux Packets

- Decompress

- Frame Synch

**Executable 1: Software Radio**

- Images + Text

**Executable 2**

- Display
- Application
- GUI

- From USB

- Viterbi

- Phase Tracking

- Matched Filter

- Timing Tracking

- Mixer/AGC

- Filter

## Software Receiver: Frequency Drift

**Ideal Situation**

**LNB**

- EMWIN - I
-   137.225 Mhz

- IF

**Practical  Situation**

**LNB**

- EMWIN - I
-   137.225 Mhz  ± **50 khz**

- IF

## Software Receiver: Frequency Acquisition

**From USB**

**Mixer/AGC**

**Filter**

**Freq Acq**

**...**

**Frame Error**
**Detector**

**Image Files**

**Restart Freq Acq**

**Freq. Offset**

**Freq Reacq Time**
**~ 5 secs**

## Software Receiver: Capabilities

- Signals
- FSK (9.8 kbps)
- OQPSK (19.2 kbps)
- BPSK LRIT (293 kbps)
- * EMWIN/HRIT GOES R (927 kbps)
- Robustness
- Automatic Reacquisition system
- Current Speed Capability
- 1.4 Msymbols/second

- * This signal does not currently exist
-    We assume it’s the same as current LRIT at a higher rate

## Software Receiver: GOES-R Performance

**User’s** **LNA/LNB and Dish Requirements**
- 1 meter dish with G/T -0.3 dB/K
- LNA/LNB Output Eb/No: 4.6 dB
**EMWIN-LRIT Solution Specifications**
- Allowable Implementation Loss:  ≤ 2.0 dB
- * Measured-Computed Imp. Loss:** **1.8 dB
- Remaining System Link Margin: **2.2 dB**
- System carrier offset resilience: 50 kHz

- The Implementation loss does not include Reed-Solomon Decoding
- and assumes an AWGN channel model.

## Demonstration: Setup

**LNB**

- 136 Mhz
-       –
- 140 Mhz

**Werner Labs**
**3 foot by 2 foot Dish**
**G/T~ -0.3 dB/K**** **

**USB**

**AID**

**IF**

## Demonstration: Data Capture

**Spectrum**

**Tracked Data Samples**

- EMWIN-I
- FSK Signal

- LRIT
- BPSK Signal

- EMWIN-N
- OQPSK Signal

## Demonstration: Fast Playback

- Derandomization

- Reed Solomon

- Demux Packets

- Decompress

- Frame Synch

- Images

- Viterbi

- Phase Tracking

- Matched Filter

- Timing Tracking

- Mixer/AGC

- Filter

- From USB

- Record to File

**Capture Phase**

**Fast Playback Phase**

- From Recorded File

## Hardware: Aerospace IF Digitizer (AID)

**USB**

**ADC**

## Hardware: Aerospace IF Digitizer

**FPGA**

**USB**

**ADC**

**Filter**

**AGC**

- Total Cost < $100

- $15

- Filter is the only
-  System Dependent
- Component

- Powered by USB

## Hardware: External Casing

- Automatic Power Meter

## Summary of User Impact

**Capability**
- Symbol rate			1.4 Mega-symbols/s
- Waveform			LRIT, EMWIN-I, EMWIN-N, EMWIN/HRIT-R
**Flexibility**
- Handles all IF frequencies of interest (AID)
- Handles all modulation types (FSK, OQPSK, BPSK)
- All Modulation parameters controlled in software
**The Future**
- Leverages Computing Technology
- Leverages Open Source Software Community
- Leverages emerging COTS technology
**Hardware Cost**
- Custom AID		<$100 (Parts Only)
- COTS Digitizer  		$775 (Full Retail)

## BACKUP SLIDES

## Thank you !

- Questions ?

**“****All trademarks, service marks, and trade names are the property of their respective owners”**

## Simulated BER System Performance 

- LRIT BER System Performance compared to Theoretical

- 2 dB Implementation
- Loss

## GNU radio framework

- Similar to Object Oriented version of simulink
- Basic communication blocks
- Information flow system
- Streaming data
- Ring buffers between blocks
- Linux environment adapted to windows VS 2003
- Open Source block repository
- Ideal framework for real-time receiver design
- Disadvantage: Most blocks slow without optimization

## GNU Radio Optimizations

- Without optimization, 100 kbits/second
- First optimization
- Intel compiler with new project settings
- Second optimization
- Used Intel specific functions from Intel Performance Primitive Library
- Third optimization
- Flexible decimation in hardware
- Removed software decimators and resamplers
- 900 kbps possible using 2 samples per symbol

## IF Board Block Diagram

- Parts Cost: < $100
- IF Range: 134 Mhz – 146 Mhz
- Downsampling Range: 4-256
- Bandwidth: – Up to 10 Mhz
- Symbol Rate Range: 0 - 8 Msymbols/sec

## L-Band Hardware

**L-Band Hardware**

- Parts Cost: < $100
- RF Range: 1460 Mhz – 2090 Mhz
- Downsampling Range: 4-256
- Bandwidth: – Up to 10 Mhz
- Symbol Rate Range: 0 - 8 Msymbols/sec

## Throughput Verification

- Signal
- Generator

- 137.5 Mhz
- with Viterbi

- IF

- USB

**S/W Receiver**
**+**
**Imager**

- PC

- Throughput Verification Method 1

**S/W Receiver**
**+**
**Imager**

- PC

- From Recorded File

- Throughput Verification Method 1

## Software Receiver: Multiple Cores 

- MultiCore
- CPU

- Thread 1

- Thread 2

- Core 1

- Core 2

- Single
- CPU

- Thread 1

- Thread 2

- Single
- Core

***1.4 Megasymbols/second**

- *860 ksymbols/s

_**Thread 1**_
- Filter
- Mixer
- AGC
- Phase Tracking
- Matched Filter
- Timing Tracking

_**Thread 2**_
- Viterbi
- Frame Synch
- Reed Solomon

## Decimation and Filtering

- LRIT signal 137.5 Mhz, 293.833 ksym/s
- ADC @ 64 Msps
- 2.1781 samples/symbol
- Image at 9.5 Mhz
- Fc = 9.5 Mhz
- Decimation = 108 -> 2.0168 Samples/symbol

**108**

**X**

- 9.5 Mhz

- Fs = 64e6/2M