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<head><title>How much RAW throughput can you get within a 3,500 Hz wide channel using OFDM?</title></head>
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<tr><th colspan=2><h2>How much RAW throughput can you get<br>in a 3,500 Hz wide channel using OFDM?</h2></th></tr>
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<tr><td colspan=2><b>Pushing the envelope using QPSK (2 marks and 2 spaces)</b></td></tr>
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<tr><td colspan=2><b>Ideal parameters</b></td></tr>
<tr><td>Modulation method:</td><td> QPSK (2 marks and 2 spaces)</td></tr>
<tr><td>Symbol Rate:</td><td> 44.5 baud</td></tr>
<tr><td>Guard band between tone steps:</td><td> 10 Hz </td></tr>
<tr><td>Tone channel width:</td><td> ~55 Hz</td></tr>
<tr><td>Actual "filter" bandpass:</td><td> 3,200 Hz</td></tr>
<tr><td>Max. Number of tones:</td><td> 60</td></tr>
<tr><td>RAW Throughput:</td><td> 5,340 bps</td></tr>
<tr><td colspan=2> </td></tr>
<tr><td colspan=2><b>Best Effort </b> </td></tr>
<tr><td>Modulation method:</td><td> QPSK (2 marks and 2 spaces)</td></tr>
<tr><td>Symbol Rate:</td><td> 50 baud</td></tr>
<tr><td>Guard band between tone steps:</td><td> 6 Hz </td></tr>
<tr><td>Tone channel width:</td><td> ~56 Hz</td></tr>
<tr><td>Actual "filter" bandpass:</td><td> 3,400 Hz (what you might obtain using an SDR-1000 radio)</td></tr>
<tr><td>Max. Number of tones:</td><td> 60</td></tr>
<tr><td>RAW Throughput:</td><td> 6,000 bps</td></tr>
<tr><td colspan=2> </td></tr>
<tr><td colspan=2><b>Pushing the envelope at a higher baud rate</b></td></tr>
<tr><td>Modulation method:</td><td> QPSK (2 marks and 2 spaces)</td></tr>
<tr><td>Symbol Rate:</td><td> 60 baud</td></tr>
<tr><td>Guard band between tone steps:</td><td> 6 Hz </td></tr>
<tr><td>Tone channel width:</td><td> ~66 Hz</td></tr>
<tr><td>Actual "filter" bandpass:</td><td> 3,400 Hz (what you might obtain using an SDR-1000 radio)</td></tr>
<tr><td>Max. Number of tones:</td><td> 51</td></tr>
<tr><td>RAW Throughput:</td><td> 6,120 bps</td></tr>
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<tr><td colspan=2><b>Pushing the envelope using QPSK (16-QAM? 4 marks and 4 spaces)</b></td></tr>
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<tr><td colspan=2><b>Ideal parameters</b></td></tr>
<tr><td>Modulation method:</td><td> 16-QAM (4 marks and 4 spaces)</td></tr>
<tr><td>Symbol Rate:</td><td> 44.5 baud</td></tr>
<tr><td>Guard band between tone steps:</td><td> 10 Hz </td></tr>
<tr><td>Tone channel width:</td><td> ~55 Hz</td></tr>
<tr><td>Actual "filter" bandpass:</td><td> 3,200 Hz</td></tr>
<tr><td>Max. Number of tones:</td><td> 60</td></tr>
<tr><td>RAW Throughput: </td><td> 10,680 bps</td></tr>
<tr><td colspan=2>Note that this will probably require a higher SNR (perhaps as much as 3-5 dB) than DQPSK so you will need to run higher power or use more of your RAW throughput for a more robust FEC.</td></tr>
<tr><td colspan=2> </td></tr>
<tr><td colspan=2><b>Best Effort </b> </td></tr>
<tr><td>Modulation method</td><td>: 16-QAM? (4 marks and 4 spaces)</td></tr>
<tr><td>Symbol Rate: </td><td> 50 baud</td></tr>
<tr><td>Guard band between tone steps:</td><td> 6 Hz</td></tr>
<tr><td>Tone channel width:</td><td> ~56 Hz</td></tr>
<tr><td>Actual "filter" bandpass:</td><td> 3,400 Hz (what you might obtain using an SDR-1000 radio)</td></tr>
<tr><td>Max. Number of tones:</td><td> 60</td></tr>
<tr><td>RAW Throughput:</td><td> 12,000 bps</td></tr>
<tr><td colspan=2>Note that this will probably require a higher SNR (perhaps as much as 3-5 dB) than DQPSK so you will need to run higher power or use more of your RAW throughput for a more robust FEC.</td></tr>
<tr><td colspan=2> </td></tr>
<tr><td colspan=2><b>Pushing the envelope at a higher baud rate</b></td></tr>
<tr><td>Modulation method:</td><td> 16-QAM? (4 marks and 4 spaces)</td></tr>
<tr><td>Symbol Rate:</td><td> 60 baud</td></tr>
<tr><td>Guard band between tone steps:</td><td> 6 Hz </td></tr>
<tr><td>Tone channel width:</td><td> ~66 Hz</td></tr>
<tr><td>Actual "filter" bandpass:</td><td> 3,400 Hz (what you might obtain using an SDR-1000 radio)</td></tr>
<tr><td>Max. Number of tones:</td><td> 51</td></tr>
<tr><td>RAW Throughput: </td><td> 12,240 bps</td></tr>
<tr><td colspan=2>Note that this will probably require a higher SNR (perhaps as much as 3-5 dB) than DQPSK so you will need to run higher power or use more of your RAW throughput for a more robust FEC.</td></tr>
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<tr><th>
<a href=http://www.its.bldrdoc.gov/fs-1052/52-appa.htm>FS-1052: Appendix A</a> <font color=darkgreen><b>39-TONE PARALLEL MODEM</b>
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