802.11b CCK BER and PER Performance

Introduction

WLAN_80211b_PER_prj design examples are described in this chapter.

• WLAN_80211b_5_5Mbps_AWGN_System.dsn: BER and PER performance for 802.11b 5.5 Mbps systems with CCK modulation under AWGN channel.
• WLAN_80211b_11Mbps_AWGN_System.dsn: BER and PER performance for 802.11b 11 Mbps systems with CCK modulation under AWGN channel.

For any digital communication system, the relationship between received signal power to noise-power spectral density P _s /N ₀ and received bit energy to noise-power spectral density E _b /N ₀ is as follows:

where Rb = data rate(bits/s), and solving for N _o in dBm/Hz, we can obtain,

So, in WLAN_80211b_PER_prj, we can achieve NDensity according to above function.

BER and PER Performance, AWGN Channel 5.5 Mbps

WLAN_80211b_5_5Mbps_AWGN_System.dsn

Features

• Data rate = 5.5Mbps, modulation = CCK
• Carrier frequency offset between transmitter and receiver is 50 kHz
• BER and PER vs. Eb/N0 on AWGN channel curves are displayed

Description

This design shows system performance of 802.11b with 5.5Mbps data rate and CCK modulation on an AWGN channel. A burst length of 500 bytes is simulated.
The top-level schematic is shown in the following figure. This design contains SignalSource, Noise, Receiver, and BERPER subnetworks. SignalSource parameters are contained in Signal_Generation_VARs; Noise and BERPER parameters are contained in RF_Channel_Measurement_VARs; Receiver parameters are contained in the Receiver_VARs.

WLAN_80211b_5_5Mbps_AWGN_System.dsn Schematic

The SignalSource subnetwork (see the following figure) generates a signal source based on user settings.

Signal Source Subnetwork Schematic

The Receiver subnetwork (see the following figure) receives an RF signal and demodulates the signal as bit streams; it also detects the start of frame and completes the transition from received sequences to frequency offset estimation sequences, estimates the frequency offset caused by the carrier differences between transmitter and receiver. A decision feedback equalized is implemented to equalize the received signal and remove the fixed rotation caused by frequency offset. The equalized signal is then fed into the CCK demodulator and demodulated into bit streams.

Receiver Subnetwork Schematic

The BERPER subnetwork, (see the following figure) measures system BER and PER.

BERPER Subnetwork Schematic

Simulation Results

Simulation results displayed in WLAN_80211b_5_5Mbps_AWGN_System.dds are shown in the following figure.

Reference data points are shown in page Equations.

Simulation Results

Benchmark

• Hardware platform: Pentium IV, 1.8 GHz, 512 MB memory
• Software platform: Windows XP, ADS 2003A
• Data points: Eb/N0 values is set from 7 to 10 dB
• Simulation time: 1.5 hours

References

1. IEEE Standard 802.11b-1999, "Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: High-speed Physical Layer Extension in the 2.4GHz Band," 1999.
2. Intersil, "Direct Sequence Spread Spectrum Baseband Processor with Rake Receiver and Equalizer," Data Sheet, FN4856.2, December 2001.

BER and PER Performance, AWGN Channel 11 Mbps

WLAN_80211b_11Mbps_AWGN_System.dsn

Features

• Data rate = 11 Mbps, modulation = CCK
• Carrier frequency offset between transmitter and receiver = 50 kHz
• BER and PER vs. Eb/N0 on AWGN channel curves are displayed

Description

This design shows system performance with 11 Mbps data rate and CCK modulation on an AWGN channel. A burst length of 500 bytes is simulated.

The top-level schematic is shown in the following figure. This design contains SignalSource, Noise, Receiver, and BERPER subnetworks. SignalSource parameters are contained in Signal_Generation_VARs; Noise and BERPER parameters are contained in RF_Channel_Measurement_VARs; Receiver parameters are contained in Noise_Vars.

WLAN_80211b_11Mbps_AWGN_System.dsn Schematic

The SignalSource subnetwork (see the following figure) generates a signal source based on user settings.

Signal Source Subnetwork Schematic

The Receiver subnetwork (see the following figure) receives an RF signal and demodulates the signal into bit streams; it also detects the start of frame and completes the transition from received sequences to frequency offset estimation sequences, estimates the frequency offset caused by the carrier differences between transmitter and receiver. A decision feedback equalized is implemented to equalize the received signal and remove the fixed rotation caused by frequency offset. The equalized signal is then fed into the CCK demodulator and demodulated into bit streams.

Receiver Subnetwork Schematic

The BERPER subnetwork (see the following figure) measures system BER and PER.

BERPER Subnetwork Schematic

Simulation Results

Simulation results displayed in WLAN_80211b_11Mbps_AWGN_System.dds are shown in the following figure.

Reference data points are shown in page Equations.

Simulation Results

Benchmark

• Hardware platform: Pentium IV, 1.8 GHz, 512 MB memory
• Software platform: Windows XP, ADS 2003A
• Data points: Eb/N0 values is set from 7 to 10 dB
• Simulation time: 1.5 hours

References

1. IEEE Standard 802.11b-1999, "Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: High-speed Physical Layer Extension in the 2.4GHz Band," 1999.
2. IIntersil, "Direct Sequence Spread Spectrum Baseband Processor with Rake Receiver and Equalizer," Data Sheet, FN4856.2, December 2001.