Abdul-Aziz.M Al-Yami Khurram Masood Case Study: Phase III Transmitter Receiver Simulation

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

Frequency bands and data rates 9/23/20153

4 Frequency bands and data rates

5 PHY – 2.4 GHz Mode Each symbol (i.e. 4 bits) is represented by one of chip sequences First 8 sequences are cyclic shifts of one 32-chip sequence, last 8 are cyclic shifts of another sequence (see next slide)

6 … … PHY – 2.4 GHz Mode

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

8 PHY – 2.4 GHz Mode Offset-QPSK with half-sine pulse shaping

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 –One to (zero’s complement) BPSK modulation with raised cosine pulse shaping with roll-off = 1.0 (100 % excess bandwidth)

2450 MHz DSSS PHY with O-QPSK  A 2450 MHz DSSS PHY employing O-QPSK modulation provides  250 kbps data rate 9/23/201510

BER vs SNR 9/23/201511

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

BER vs SNR 9/23/201513

Semi-analytic Simulation (No ISI) 9/23/ Delay Estimation

Semi-analytic Simulation (No ISI) 9/23/ Eye diagram

Semi-analytic Simulation (No ISI) 9/23/ Noise estimation

Semi-analytic Simulation (No ISI) 9/23/ BER vs SNR

Semi-analytic Simulation (with ISI) 9/23/ Delay Estimation

Semi-analytic Simulation (with ISI) 9/23/ Eye diagram

Semi-analytic Simulation (with ISI) 9/23/ Noise estimation

Semi-analytic Simulation (with ISI) 9/23/ BER vs SNR