802.11h MAC Functions
What are the MAC functions in IEEE 802.11h?
The MAC functions in 802.11h primarily support Dynamic Frequency Selection (DFS) and Transmit Power Control (TPC) to manage interference and regulatory compliance.
How does the MAC layer support Dynamic Frequency Selection (DFS)?
The MAC scans channels for radar signals before transmission and enforces channel switching if radar is detected.
What role does the MAC play in Transmit Power Control (TPC)?
The MAC layer controls the transmit power level of the radio, adjusting it to minimize interference while maintaining communication quality.
How does MAC ensure compliance with regulatory requirements?
It implements DFS and TPC algorithms to conform with regional rules for spectrum use, especially in the 5 GHz band.
What is the Channel Availability Check (CAC) in MAC functions?
CAC is the process where the MAC monitors a channel for radar signals for a set duration before permitting use.
How does the MAC layer handle radar detection?
Upon detecting radar pulses, the MAC immediately initiates channel move procedures to vacate the channel.
What are Channel Move Announcements in MAC?
These are notifications sent by the MAC to connected devices to inform them about upcoming channel changes due to radar detection.
How does MAC manage Channel Availability Check Time (CACT)?
MAC enforces a mandatory wait time (CACT) on a new channel to ensure no radar presence before usage.
What is the impact of MAC on channel switching delay?
MAC processes introduce a delay during DFS channel switching to maintain regulatory compliance and network stability.
How does MAC coordinate power adjustment with TPC?
The MAC calculates and applies appropriate transmit power based on received signal strength and regulatory limits.
Does MAC function in 802.11h affect frame timing?
Yes, certain MAC timings, like defer times and interframe spaces, may be adjusted to accommodate DFS and TPC requirements.
How does the MAC handle non-compliant devices in the network?
The MAC may limit communication or reject devices that don’t support DFS and TPC in regulatory domains requiring 802.11h.
What is the role of MAC in power constraint element?
MAC uses power constraint elements to inform clients of transmit power limitations on specific channels.
How does MAC affect beacon transmissions in 802.11h?
MAC inserts DFS and TPC information in beacon frames to inform clients of channel and power management status.
How is MAC involved in radar pulse pattern recognition?
MAC processes radar pulse signatures reported by the PHY layer and triggers DFS actions accordingly.
Does 802.11h MAC support multiple channel switching?
Yes, MAC can manage sequential channel switches if multiple radar detections occur on different channels.
What MAC management frames are specific to 802.11h?
Frames like Channel Switch Announcement (CSA) and Power Constraint Information Elements are added for regulatory functions.
How does MAC handle DFS non-occupancy periods?
After radar detection, MAC enforces a non-occupancy period on the affected channel before it can be reused.
Is MAC layer involvement in 802.11h automatic or manual?
MAC functions related to DFS and TPC operate automatically without user intervention.
How does MAC contribute to overall Wi-Fi network stability in 802.11h?
By managing channel availability and transmit power dynamically, MAC helps prevent interference and ensures stable connections.
Topics in this section,
Reference links