Processing Gain Info

FCC ID: QAX-VPN350

Operational Description

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FCCID_269470

CISCO CONFIDENTIAL Mercury processing gain J. Friedmann add 3dB if unique theoretical codes for I & Q processing gain dB measured 10 log (chip (minus 1 dB for (add last two processing data rates modulation used symbol rates chip rate chip per bit per bit) implementation) columns) gain 11 1 mb/s BPSK 1 mbps 11 mbps (same code for I & Q) 10.7 dB 10.7 dB 10.8 dB 11 2 mb/s QPSK 1 mbps 11 mbps (same code for I & Q) 10.7 dB 10.7 dB 10.8 dB 8 5.5 mb/s CCK 1.375 mbps 8 mbps (8 for I & 8 for Q) 9 dB 2 dB 11 dB 10.7 dB 8 11 mb/s CCK 1.375 mbps 8 mbps (8 for I & 8 for Q) 9 dB 2 dB 11 dB 10.6 dB 9/25/00 1 PG_Mercury_th_writeup.xls

PRODUCT NAME: Cisco Merucry Radio NAME OF TEST: The Processing Gain of a Direct Sequence System. FCC Part 15.247 (e) specifies: The processing gain of a direct sequence system shall be at least 10 dB. Guidance on measurement by FCC The processing gain may be measured using the CW jamming margin method. The test consists of stepping a signal generator in 50khz increments across the passband of the system. At each point, the generator level required to the produce the recommended Bit Error Rate (10—5) is recorded. This is the jammer level. The output power of the transmitting unit is measured at the same point. The Jammer to Signal (J/S) ratio is then calculated. Discard the worst 20% of the J/S data points. Total losses in a system including transmitter and receiver, should be assumed to be no more than 2 dB. therefore, processing gain = S/N + Mj + Lsys Where : S/N = Signal to noise ratio required at the receiver output for 10—5 error rate of a ideal receiver for your demodulation scheme Mj = Jammer to signal ratio Lsys = System losses (2d4B max) Test results : for 1 mb data rate: S/N = 13 dB ; taken from Wireless Information Networks by Pahlavan & Levesque Mj = — 4.2 dB ; worst case jamming margin from tests in lab Lsys = 2.0 dB ; system losses therefore the processing gain at Imb is 13 dB — 4.2 dB + 2.0 dB = 10.8 dB for 2 mb data rate: S/N = 13 dB ; taken from Wireless Information Networks by Pahlavan & Levesque Mj = — 4.2 dB ; worst case jamming margin from tests in lab Lsys = 2.0 dB ; system losses therefore the processing gain at 2mb is 13 dB — 4.2 dB + 2.0 dB = 10.8 dB Cisco Confidential 2 4/13/00

for 5.5 mb data rate: S/N = 13.6 dB ; taken from Harris CCK encoding modulation Mj = — 4.4 dB ; worst case jamming margin from tests in lab (after 20% discard) Lsys = 2.0 dB ; system losses therefore the processing gain at 5.5mb is 13.6 dB — 4.4 dB + 2.0 dB = 11.2 dB for 11 mb data rate: S/N = 16.0 dB ; taken from Harris CCK encoding modulation MJ =— 7.4 dB ; worst case jamming margin from tests in lab (after 20% discarded) Lsys = 2.0 dB ; system losses therefore the processing gain at 11mb is 16.0 dB — 7.4 dB + 2.0 dB = 10.6 dB Cisco Confidential 3 4 /13/00


Document Created: 2002-09-11 09:58:49
Document Modified: 2002-09-11 09:58:49
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