80211a Receiver

Introduction

WLAN_80211a_Rx_prj project for IEEE 802.11a receiver test and verification design examples are described in this chapter.

Specification requirements

Receiver performance requirements are listed in the following table.

Receiver Requirements
Data Rate (Mbps) Minimum Sensitivity (dBm) Adjacent Channel Rejection (dB) Alternate Adjacent Channel Rejection (dB)
6 -82 16 32
9 -81 15 31
12 -79 13 29
18 -77 11 27
24 -74 8 24
36 -70 4 20
48 -66 0 16
54 -65 -1 15

Receiver Minimum Input Level Sensitivity Measurement at 6 Mbps

WLAN_80211a_RxSensitivity_6Mbps.dsn

Features

Description

This design is an example of WLAN receiver minimum input level sensitivity measurement at a data rate of 6 Mbps. According to specification [1] 17.3.10.1, the packet error rate (PER) must be less than 10% at a PSDU length of 1000 bytes and rate-dependent input levels (or less) according Table 91. The minimum input levels are measured at the antenna connector (NF of 10 dB and 5 dB implementation margins are assumed). For data rate of 6 Mbps, the value is -82 dBm.

The schematic for this design is shown in the following figure. Parameters that can be changed by users are contained in Signal_Generation_VARs, RF_Channel_VARs, and Measurement_VARs.

WLAN_80211a_RxSensitivity_6Mbps Schematic

Simulation Results

Simulation results displayed in WLAN_80211a_RxSensitivity.dds are shown in the following figure. BER and PER at given input levels are simulated.

WLAN_80211a_RxSensitivity.dds

Benchmark

References
  1. IEEE Standard 802.11a-1999, "Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: High-speed Physical Layer in the 5 GHz Band," 1999.

Receiver Minimum Input Level Sensitivity Measurement at 24 Mbps

WLAN_80211a_RxSensitivity_24Mbps.dsn

Features

Description

This design is an example of WLAN receiver minimum input level sensitivity measurement at a data rate of 24 Mbps.
According to specification [1] 17.3.10.1: the packet error rate (PER) must be less than 10% at a PSDU length of 1000 bytes; for rate-dependent input, levels must be according to Table 91 (or less). The minimum input levels are measured at the antenna connector (NF of 10 dB and 5 dB implementation margins are assumed). For data rate of 24 Mbps, the value is -74 dBm.

The RF signal is generated in two stages: first, to modulate a baseband signal to IF; second, to up-convert an IF signal to an RF signal. The first stage is implemented by subnetwork WLAN_80211a_RF. RF_Tx_Ifin is used to upconvert the IF signal to an RF signal. In the receiver, the RF signal is downconverted to IF frequency; then, an IF signal is demodulated in WLAN_80211a_RF_RxFSync.

The schematic for this design is shown in the following figure.

WLAN_80211a_RxSensitivity_24Mbps.dsn

In the schematic, Signal_Generation_VARs defines key transmitter variables, and RF_Channel_VARs defines key variables for up- and down-conversion.

Rate, Length, Order and Idle are used to define a baseband burst. Users can change Rate from 0 to 8 to perform sensitivity tests for 6, 9, 12, 18, 24, 27, 36, 48, and 54 Mbps data rates, respectively. SignalPower determines the transmitted power for an IF transmitter. VRef is the reference voltage for output power calibration. IF_BW is set to 20MHz for 802.11a systems.

There are seven key variables: IF_Freq1, IF_Freq2, RF_Freq, RF_BW, Tx_Gain and Prx in RF_Channel_VARs. IF_Freq1 and IF_Freq2 are two IF frequency. RF_Freq means center frequency of IEEE 802.11a system in simulation system. RF_BW is set to 20MHz for 802.11a systems. Prx denotes 802.11a receiver power. Power=dbmtow(SignalPower-Tx_Gain) in the WLAN_80211a_RF signal source component and TX_Gain=Tx_Gain in the RF_TX_IFin component. So, the total transmitted power is the Signal_Generation_VARs SignalPower setting after up-conversion. Table 89 in the specification defines the maximum allowable output power for different frequency bands:

Users can set SignalPower and RF_Freq as needed.
The GainRF attenuator subnetwork's Gain parameter is set as dbpolar(Prx-SignalPower,0). After GainRF, the power of 802.11a is Prx-SignalPower+Tx_Gain+SignalPower-Tx_Gain=Prx. In the specification, NF of 10 and 5dB implementation margins are assumed. So, Rx_NF=10 in RF_RX_IFout.

The RF_RX_IFout subnetwork's RX_AntTemp is the receiving antenna noise temperature (in Kelvin). RX_AntTemp=20+273.15 means the test is performed in an office environment; users can change the temperature setting. Moreover, RX_Gain in RF_RX_IFout varies with the Order parameter and the relation is described by equation 82-6*(Order-6).

The following table lists minimum sensitivity performance according to data rate in the 802.11a specification. Users can sweep Prx, run the design and observe the PER. If the Prx is less than the value in the table when PER is less than 10%, the sensitivity measurement passes.

Minimum Sensitivity Performance
Data Rate (Mbps) Minimum Sensitivity (dBm)
6 -82
9 -81
12 -79
18 -77
24 -74
36 -70
48 -66
54 -65

Simulation Results

Simulation results displayed in WLAN_80211a_RxSensitivity.dds are shown in the following figure. BER and PER at different input levels are simulated.

WLAN_80211a_RxSensitivity.dds

Benchmark

References
  1. IEEE Standard 802.11a-1999, "Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: High-speed Physical Layer in the 5 GHz Band," 1999.

Receiver Minimum Input Level Sensitivity Measurement at 54 Mbps

WLAN_80211a_RxSensitivity_54Mbps.dsn

Features

Description

This design is an example of WLAN receiver minimum input level sensitivity measurement at data rate of 54 Mbps. According to specification [1] 17.3.10.1, the packet error rate (PER) shall be less than 10% at a PSDU length of 1000 bytes for rate-dependent input levels shall be the numbers listed in Table 91 or less. The minimum input levels are measured at the antenna connector (NF of 10 dB and 5 dB implementation margins are assumed). For data rate of 54 Mbps, the value is -65 dBm.

The schematic for this design is shown in the following figure. Parameters that can be changed by users are contained in Signal_Generation_VARs, RF_Channel_VARs, and Measurement_VARs.

WLAN_80211a_RxSensitivity_54Mbps.dsn

Simulation Results

Simulation results displayed in WLAN_80211a_RxSensitivity.dds are shown in the following figure. BER and PER at different input levels are simulated.

WLAN_80211a_RxSensitivity.dds

Benchmark

References
  1. IEEE Standard 802.11a-1999, "Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: High-speed Physical Layer in the 5 GHz Band," 1999.

Adjacent Channel Rejection Measurement at 9 Mbps

WLAN_80211a_RxAdjCh_9Mbps.dsn

Features

Description

The adjacent channel rejection shall be measured by setting the desired signal's strength 3 dB above the rate-dependent sensitivity as specified in Table 91 of IEEE Standard. 802.11a-1999 and raising the power of the interfering signal until the 10% packet error rate (PER) is caused for a PSDU length of 1000 bytes. The power difference between the interfering and the desired channel is the corresponding adjacent channel rejection. The interfering signal in the adjacent channel shall be a conforming OFDM PHY signal, unsynchronized with the signal in the channel under test. For a conforming OFDM PHY the corresponding rejection shall be no less than specified in Table 91 of IEEE Standard. 802.11a-1999.

In this design, the adjacent channel rejection of data rate 9 Mbps is measured; The power of interfering signal is raised to the rate-dependent adjacent channel rejection 15 dB as specified in Table 91 of IEEE Standard. 802.11a-1999, then a PER less than 10% shall be achieved.

The top-level schematic for this design is shown in the following figure.

WLAN_80211a_RxAdjCh_9Mbps.dsn Schematic

Simulation Results

Simulation results are shown in the following figure.

Simulation Results

The simulation results show that when the adjacent channel rejection value (ACR) is set to 15 dB according to the table of specification requirements, the PER is 0.000 which is much lower than 10%, so this system is consistent with the requirements of adjacent channel rejection of the IEEE Standard. 802.11a-1999.

Benchmark

References
  1. IEEE Standard 802.11a-1999, "Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: High-speed Physical Layer in the 5 GHz Band," 1999.

Adjacent Channel Rejection Measurement at 18 Mbps

WLAN_80211a_RxAdjCh_18Mbps.dsn

Features

Description

The adjacent channel rejection shall be measured by setting the desired signal's strength 3dB above the rate-dependent sensitivity as specified in Table 91 of IEEE Standard. 802.11a-1999 and raising the power of the interfering signal until the 10% packet error rate (PER) is caused for a PSDU length of 1000 bytes. The power difference between the interfering and the desired channel is the corresponding adjacent channel rejection. The interfering signal in the adjacent channel shall be a conforming OFDM PHY signal, unsynchronized with the signal in the channel under test. For a conforming OFDM PHY the corresponding rejection shall be no less than specified in Table 91 of IEEE Standard. 802.11a-1999.

In this design, the adjacent channel rejection of data rate 18 Mbps is measured; The power of interfering signal is raised to the rate-dependent adjacent channel rejection 11dB as specified in Table 91 of IEEE Standard. 802.11a-1999, then a PER less than 10% shall be achieved.

The top-level schematic for this design is shown in the following figure.

WLAN_80211a_RxAdjCh_18Mbps.dsn Schematic

Simulation Results

Simulation results are shown in the following figure.

Simulation Results

The simulation results show that when the adjacent channel rejection value (ACR) is set to 11 dB according to the table of specification requirements, the PER is 0.000 which is much lower than 10%, so this system is consistent with the requirements of adjacent channel rejection of the IEEE Standard. 802.11a-1999.

Benchmark

References
  1. IEEE Standard 802.11a-1999, "Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: High-speed Physical Layer in the 5 GHz Band," 1999.

Adjacent Channel Rejection Measurement at 36 Mbps

WLAN_80211a_RxAdjCh_36Mbps.dsn

Features

Description

The adjacent channel rejection shall be measured by setting the desired signal's strength 3dB above the rate-dependent sensitivity as specified in Table 91 of IEEE Standard. 802.11a-1999 and raising the power of the interfering signal until the 10% packet error rate (PER) is caused for a PSDU length of 1000 bytes. The power difference between the interfering and the desired channel is the corresponding adjacent channel rejection. The interfering signal in the adjacent channel must be a conforming OFDM PHY signal, unsynchronized with the signal in the channel under test. For a conforming OFDM PHY the corresponding rejection cannot be less than specified in Table 91 of IEEE Standard. 802.11a-1999.

In this design, the adjacent channel rejection of data rate 36 Mbps is measured. The power of interfering signal is raised to the rate-dependent adjacent channel rejection 4 dB as specified in Table 91 of IEEE Standard. 802.11a-1999, then a PER less than 10% shall be achieved.

The top-level schematic for this design is shown in the following figure.

WLAN_80211a_RxAdjCh_36Mbps.dsn Schematic

Simulation Results

Simulation results are shown in the following figure.

Simulation Results

The simulation results show that when the adjacent channel rejection value (ACR) is set to 4 dB according to the table of specification requirements, the PER is 0.000 which is much lower than 10%, so this system is consistent with the requirements of adjacent channel rejection of the IEEE Standard. 802.11a-1999.

Benchmark

References
  1. IEEE Standard 802.11a-1999, "Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: High-speed Physical Layer in the 5 GHz Band," 1999.

Non-Adjacent Channel Rejection Measurement at 12 Mbps

WLAN_80211a_RxNonAdjCh_12Mbps.dsn

Features

Description

The non-adjacent channel rejection shall be measured by setting the desired signal's strength 3dB above the rate-dependent sensitivity as specified in Table 91 of IEEE Standard. 802.11a-1999 and raising the power of the interfering signal until the 10% packet error rate (PER) is caused for a PSDU length of 1000 bytes. The power difference between the interfering and the desired channel is the corresponding non-adjacent channel rejection. The interfering signal in the non-adjacent channel shall be a conforming OFDM PHY signal, unsynchronized with the signal in the channel under test. For a conforming OFDM PHY the corresponding rejection shall be no less than specified in Table 91 of IEEE Standard. 802.11a-1999.

In this design, the non-adjacent channel rejection of data rate 12 Mbps is measured; The power of interfering signal is raised to the rate-dependent adjacent channel rejection 29 dB as specified in Table 91 of IEEE Standard. 802.11a-1999, then a PER less than 10% shall be achieved.

The top-level schematic for this design is shown in the following figure.

WLAN_80211a_RxNonAdjCh_12Mbps.dsn Schematic

Simulation Results

Simulation results are shown in the following figure.

Simulation Results

The simulation results show that when the non-adjacent channel rejection value (NACR) is set to 29 dB according to the table of specification requirements, the PER is 0.000 which is much lower than 10%, so this system is consistent with the requirements of non-adjacent channel rejection of the IEEE Standard. 802.11a-1999.

Benchmark

References
  1. IEEE Standard 802.11a-1999, "Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: High-speed Physical Layer in the 5 GHz Band,"1999.

Non-Adjacent Channel Rejection Measurement at 48 Mbps

WLAN_80211a_RxNonAdjch_48Mbps.dsn

Features

Description

The non-adjacent channel rejection must be measured by setting the desired signal strength 3dB above the rate-dependent sensitivity as specified in IEEE Standard. 802.11a-1999, Table 91, and raising the power of the interfering signal until the 10% packet error rate (PER) is caused for a PSDU length of 1000 bytes. The power difference between the interfering and the desired channel is the corresponding non-adjacent channel rejection.

The interfering signal in the non-adjacent channel must be a conforming OFDM PHY signal, unsynchronized with the signal in the channel under test. For a conforming OFDM PHY the corresponding rejection must not be less than specified in IEEE Standard. 802.11a-1999, Table 91.

In this design, the non-adjacent channel rejection of data rate 48 Mbps is measured. Power of the interfering signal is raised to the rate-dependent adjacent channel rejection 16 dB as specified in IEEE Standard. 802.11a-1999, Table 91, to achieve a PER less than 10%.

The top-level schematic for this design is shown in the following figure.

WLAN_80211a_RxNonAdjCh_48Mbps.dsn Schematic

Simulation Results

Simulation results are shown in the following figure.

Simulation Results

Simulation results show that when the non-adjacent channel rejection value (NACR) is set to 16 dB according to the table of specification requirements, the PER is 0.000 which is much lower than 10%; this system is consistent with the requirements of non-adjacent channel rejection of IEEE Standard. 802.11a-1999.

Benchmark

References
  1. IEEE Standard 802.11a-1999, "Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: High-speed Physical Layer in the 5 GHz Band," 1999.
 

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