Transmit announcement indication

What is this patent about?

’122 is related to the field of wireless network communications, specifically focusing on optimizing data transmission efficiency in protocols like IEEE 802.11. In high-speed wireless environments, reducing protocol overhead is critical for maximizing throughput. Traditional frame exchanges often require redundant addressing and control information in every packet, which consumes valuable airtime and processing resources, especially when multiple related frames are sent in quick succession to the same destination.

The underlying idea behind ’122 is to use a preceding frame as a signaling mechanism to prepare a receiver for a subsequent, streamlined transmission. By embedding a specific transmission announcement indication within an initial addressed frame, the sender can inform the receiver that another packet is immediately forthcoming. This foresight allows the second frame to be transmitted without a destination address, effectively stripping away MAC-layer overhead and relying on the context established by the first frame to ensure the data reaches the correct recipient.

The claims of ’122 focus on a method and system for transmitting a first communication frame containing both the destination's address and a specialized announcement bit, followed by a second frame that lacks that address. The invention specifically requires that this second, address-less frame follows the first after a short inter frame space (SIFS). This timing ensures that the medium remains reserved and the receiver stays synchronized, allowing the second transmission to be correctly associated with the destination identified in the first frame.

In practice, the invention works by utilizing a single bit within the HT-control field of a MAC header to act as the announcement trigger. For example, a station might send a Request to Send (RTS) or a Quality of Service (QoS) Null frame that flags the upcoming transmission. Because the receiver is alerted by the announcement bit, it knows to listen for a subsequent zero-length frame (ZLF) or data packet that arrives without the usual header identification, significantly reducing the number of bits that must be processed and transmitted over the air.

This approach differs from prior methods by eliminating the need for a full MAC header on every sequential packet sent to the same device. While standard protocols require each frame to be self-contained with full addressing, this invention creates a contextual link between frames. By leveraging the SIFS interval and the announcement bit, the system maintains a high-speed pipeline that sounds the channel or transfers data with minimal overhead, providing a more efficient use of the available radio frequency spectrum.