Wireless transmission is performed by storing, in a local memory, a header in association with reference(s) to memory locations in a separate, shared memory storing a payload for a given transmission. Each header can be associated with a QoS queue. When a selected payload is to be transmitted, a PHY preamble can begin, followed by a header from local memory, while a DMA transaction initiates to retrieve payload from the shared memory. Each retrieved portion of payload can include a link to a next location storing a next part of payload. A subsequent DMA is initiated for that part of the payload. A relatively fixed function circuit can initiate DMA and receive payload data; a programmable element can perform payload selection, for example. Multiple payloads can be aggregated (just before transmitting of a preamble) using header information stored in the fast local memory. Memory can be released after ACK of a corresponding payload.