SWRU423A July 2015 – May 2016 WL1801MOD , WL1805MOD , WL1807MOD , WL1831MOD , WL1835MOD , WL1837MOD
Block acknowledgment (BA) was initially defined in IEEE 802.11e as an optional scheme to improve the MAC efficiency. Recently, ratified amendment 802.11n enhanced this BA mechanism, making support for all 802.11n-capable devices (formally known as high throughput (HT) devices) mandatory.
Instead of transmitting an individual ACK for every MPDU (or frame), multiple MPDUs can be acknowledged together using a single BA frame. Block-Ack (BA) contains a bitmap that accounts the fragment number of the MPDUs to be acknowledged. Each bit of this bitmap represents the status (success or failure) of an MPDU.
Block acknowledgment consists of setup and tear-down phases. In the setup phase, capability information such as buffer size and BA policy are negotiated with the receiver. Once the setup phase completes, the transmitter can send frames without waiting for an ACK frame. Finally, the BA agreement is torn down with a DELBA frame.
WiLink8.0 supports BA session both for TX and RX.