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Published byElfreda Willis Modified over 9 years ago
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Abdul-Aziz.M Al-Yami Khurram Masood Case Study: Phase III Transmitter Receiver Simulation
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Physical Layer (PHY) The standard specifies the following four PHYs: 1.An 868/915 MHz direct sequence spread spectrum (DSSS) PHY employing binary phase-shift keying (BPSK) modulation 2.An 868/915 MHz DSSS PHY employing offset quadrature phase- shift keying (O-QPSK) modulation 3.An 868/915 MHz parallel sequence spread spectrum (PSSS) PHY employing BPSK and amplitude shift keying (ASK) modulation 4.A 2450 MHz DSSS PHY employing O-QPSK modulation 9/23/20152
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Frequency bands and data rates 9/23/20153
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4 Frequency bands and data rates
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5 PHY – 2.4 GHz Mode Each symbol (i.e. 4 bits) is represented by one of 16 32- chip sequences First 8 sequences are cyclic shifts of one 32-chip sequence, last 8 are cyclic shifts of another sequence (see next slide)
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6 … … PHY – 2.4 GHz Mode
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7 Chip modulation is offset-QPSK, in which the Q-branch signal is delayed by one chip period ( T c ) with respect to the I-branch signal Pulse shape is half-sine with period 2 T c
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8 PHY – 2.4 GHz Mode Offset-QPSK with half-sine pulse shaping
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9 PHY – 868/915 MHz Mode Raw bits are differentially encoded –XOR between current bit and the previous encoded bit Each coded bit mapped to a 15-chip PN sequence –Zero to 1 1 1 1 0 1 0 1 1 0 0 1 0 0 0 –One to 0 0 0 0 1 0 1 0 0 1 1 0 1 1 1 (zero’s complement) BPSK modulation with raised cosine pulse shaping with roll-off = 1.0 (100 % excess bandwidth)
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2450 MHz DSSS PHY with O-QPSK A 2450 MHz DSSS PHY employing O-QPSK modulation provides 250 kbps data rate 9/23/201510
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BER vs SNR 9/23/201511
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869/915 MHz DSSS PHY with BPSK 868/915 MHz BPSK PHY, provides 20 kb/s in the 868 MHz band and 40 kb/s in the 915 MHz band 9/23/201512
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BER vs SNR 9/23/201513
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Semi-analytic Simulation (No ISI) 9/23/201514 Delay Estimation
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Semi-analytic Simulation (No ISI) 9/23/201515 Eye diagram
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Semi-analytic Simulation (No ISI) 9/23/201516 Noise estimation
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Semi-analytic Simulation (No ISI) 9/23/201517 BER vs SNR
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Semi-analytic Simulation (with ISI) 9/23/201518 Delay Estimation
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Semi-analytic Simulation (with ISI) 9/23/201519 Eye diagram
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Semi-analytic Simulation (with ISI) 9/23/201520 Noise estimation
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Semi-analytic Simulation (with ISI) 9/23/201521 BER vs SNR
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