802.11an
IEEE 802.11an is an amendment to the Wi-Fi standard that extends 802.11a operation to wider 40 MHz channels in the 5 GHz band, enabling higher data rates up to 300 Mbps.
Category |
Description |
Use Case |
|---|---|---|
MAC Functions |
Core MAC layer responsibilities like frame delimiting, addressing, error checking. |
Managing wireless communication and reliable data delivery |
MAC Timings |
Timing parameters like SIFS, DIFS, backoff timers controlling transmission. |
Coordination of medium access and collision avoidance |
Packet Formats |
Structure of 802.11an frames including header, payload, and control frames. |
Frame parsing and network management |
Power Save |
Power saving mechanisms allowing devices to enter low power modes. |
Extending battery life while maintaining connectivity |
Interoperability |
Mechanisms for compatibility with other 802.11 standards and vendors. |
Seamless multi-vendor and multi-standard network operation |
Physical Rates |
Supported data rates and modulation schemes of 802.11an, utilizing 40 MHz channels in 5 GHz. |
Higher throughput and efficient spectrum use with wider channels |
PPDU |
Physical Protocol Data Unit format including extended preamble and data fields for 40 MHz operation. |
Synchronization and efficient data transmission over wider channels |
Standard: IEEE 802.11an (2007)
Main Features:
Core MAC responsibilities including frame delimiting, addressing, and error detection
Ensures reliable wireless communication and handles retransmissions
Manages medium access control with CSMA/CA for 5 GHz band using 40 MHz channels
Controls acknowledgments (ACK) and fragmentation/reassembly of frames
Supports enhanced throughput with wider channels and efficient spectrum use
Integrates closely with Physical Layer features unique to 802.11an
Use Cases:
Delivering high-speed Wi-Fi connectivity in 5 GHz band with 40 MHz channels
Managing medium access for increased throughput WLAN deployments
Supporting QoS, security, and robust wireless communication in dense environments
Related Functions:
Frame control and addressing schemes
Sequence control to maintain packet order
Power management signaling to optimize device battery use
Error detection and recovery mechanisms using CRC and retransmissions
Explore the details of 802.11an MAC Functions:
Standard: IEEE 802.11an (2007)
Main Features:
Defines timing parameters for frame transmission and acknowledgments over 40 MHz channels
Includes Interframe Spaces (SIFS, DIFS, PIFS, AIFS) to coordinate medium access
Specifies slot times and contention window sizes for CSMA/CA backoff in 5 GHz band
Ensures collision avoidance and fair access in high-throughput WLANs
Manages retransmission timing and acknowledgment intervals
Synchronizes MAC and PHY layers for efficient communication with wider channels
Use Cases:
Coordinating transmission timing in 5 GHz WLANs using 40 MHz channels
Minimizing collisions and optimizing network throughput
Supporting QoS through prioritized timing and access control
Related Timing Parameters:
Short Interframe Space (SIFS)
Distributed Interframe Space (DIFS)
Arbitration Interframe Space (AIFS)
Slot time and backoff timers
Explore the details of 802.11an MAC Timings:
Standard: IEEE 802.11an (2007)
Main Features:
Defines the structure of MAC and PHY layer frames used in 802.11an
Includes Frame Control, Duration, Address fields, Sequence Control, and CRC
Supports data frames, management frames, and control frames
Uses OFDM symbols with 40 MHz channel width at the PHY layer for high-speed transmission
Frame formats support addressing, QoS, and security features
Allows fragmentation and reassembly for large packets
Use Cases:
Structuring wireless packets for communication in 5 GHz WLANs with wider channels
Ensuring proper delivery, acknowledgment, and retransmission of data
Enabling interoperability between devices by standardized frame formats
Related Frame Types:
Management frames (e.g., Beacon, Probe Request)
Control frames (e.g., ACK, RTS, CTS)
Data frames (with or without QoS)
Explore the details of 802.11an Packet Formats:
Standard: IEEE 802.11an (2007)
Main Features:
Supports Power Save Mode (PSM) to reduce energy consumption on client devices
Clients enter sleep state and wake periodically to receive buffered data
Access Point buffers frames for sleeping stations and signals buffered data in beacon frames
Uses Delivery Traffic Indication Message (DTIM) to inform clients about multicast/broadcast data
Enables efficient battery usage for mobile and portable Wi-Fi devices in 5 GHz band with 40 MHz channels
Works with MAC layer mechanisms to coordinate sleep and wake cycles effectively
Use Cases:
Extending battery life of Wi-Fi enabled mobile devices operating in 5 GHz band
Reducing power consumption in IoT and embedded Wi-Fi devices
Balancing network performance with power efficiency in high-throughput WLANs
Related Mechanisms:
Beacon frame scheduling
DTIM and TIM fields for power management
Client wake-up and sleep signaling
Explore the details of 802.11an Power Saving mechanisms:
Standard: IEEE 802.11an (2007)
Main Features:
Ensures compatibility between devices from different vendors operating in 5 GHz band with 40 MHz channels
Supports coexistence with other 802.11 standards through dual-band or multi-radio devices
Defines common frame formats, signaling, and channelization to enable seamless communication
Implements clear channel assessment (CCA) and CSMA/CA for medium access coordination
Uses standardized management and control frames for association, authentication, and roaming
Facilitates coexistence and reduces interference with other wireless technologies in overlapping frequency bands
Use Cases:
Enabling multi-vendor Wi-Fi deployments in enterprise and consumer networks using 802.11an
Supporting seamless handoff and roaming in heterogeneous Wi-Fi environments
Allowing mixed 802.11 standard networks to operate efficiently without interference
Related Mechanisms:
Management frame interoperability
Frequency band and channel coordination
Standardized PHY and MAC layer procedures
Explore the details of 802.11an Interoperability mechanisms:
Standard: IEEE 802.11an (2007)
Main Features:
Supports multiple physical layer data rates from 6 Mbps up to 300 Mbps
Utilizes Orthogonal Frequency Division Multiplexing (OFDM) modulation with 40 MHz channels
Provides selectable data rates: 6, 9, 12, 18, 24, 36, 48, 54, 72, 96, 108, 120, 144, 150, 180, 216, 240, 270, and 300 Mbps depending on MCS
Adapts rates dynamically based on signal quality and channel conditions
Uses 40 MHz wide channels in the 5 GHz frequency band to increase throughput
Enables higher data throughput and improved spectral efficiency compared to 802.11a
Use Cases:
High-speed wireless networking in enterprise and home environments with wider bandwidth
Multimedia streaming, high-definition video, and low-latency applications over Wi-Fi
Wireless backhaul, bridging, and high-throughput WLAN deployments
Related Concepts:
Rate adaptation algorithms
Modulation and coding schemes (MCS)
Channel bonding and spectrum management
Explore the details of 802.11an Physical Rates:
Standard: IEEE 802.11an (2007)
Main Features:
Defines the Physical Protocol Data Unit (PPDU) structure for 802.11an
Includes a preamble for synchronization, channel estimation, and MIMO training
Contains SIGNAL and HT-SIG fields specifying data rate, length, and MIMO parameters
Payload carries the MAC frame encoded with OFDM modulation using 40 MHz channels
Supports multiple spatial streams with adaptive modulation and coding
Enables high-throughput and reliable wireless data transmission in 5 GHz band
Use Cases:
Ensuring proper encapsulation of data for transmission over 802.11an PHY
Synchronization and channel estimation for MIMO communication
Facilitating robust, high-speed wireless communication with multiple antennas
Related Concepts:
OFDM and MIMO symbol structures
Service field, tail bits, and training sequences
Channel coding, interleaving, and spatial stream mapping
Explore the details of 802.11an PPDU: