Antenna Diversity

There's a wide variety of how transmit and receive diversity is implemented on various Atheros wireless chips.

• An overview of antenna diversity
• Which chips support which types of diversity

• How the external antenna switch tables work
• Classic transmit and (fast) receive diversity using an external antenna switch
• Diversity using LNA mixing
• Using an external antenna switch on a MIMO device to add transmit/receive antennas
• How the sectored antenna support works
• Using the shift register for antenna diversity on 11n parts

• Antenna Diversity on the AR5212 and related 802.11abg NICs
• (Slow) External Antenna Switch Diversity on the AR5416 and later 802.11n chips
• LNA, Bluetooth and External Antenna Switch Diversity on the AR9285
• External and Bluetooth Antenna Switch Diversity on the AR9287 + Bluetooth Combo NICs
• Using the per-descriptor TX antenna shift register on the AR5416 and later hardware

• https://en.wikipedia.org/wiki/Diversity_combining
• https://en.wikipedia.org/wiki/MIMO
• https://en.wikipedia.org/wiki/Maximal-ratio_combining
• https://en.wikipedia.org/wiki/Space-time_block_code