UE MAC Subheader Buffer Status Reporting in LTE

The patent applies preliminary action by pre-defining the meaning of two reserved bits in the MAC subheader before actual buffer status reporting is needed. These bits are prepared in advance as part of the MAC header structure, allowing immediate buffer status indication without requiring separate report messages. The base station interprets these pre-positioned bits to determine buffer status, enabling continuous accurate knowledge without additional transmission overhead.

The patent uses the MAC subheader as an intermediary carrier to convey buffer status information. Instead of using a dedicated buffer status report message, the buffer status is embedded within the existing MAC subheader structure through reserved bits. This intermediary approach allows the buffer status to be transmitted continuously with data packets, providing both accuracy and frequency without requiring separate reporting mechanisms.

The patent applies universality by making the MAC subheader serve multiple functions: it continues to carry its original data transmission control information while simultaneously embedding buffer status indication through the same structure. The reserved bits in the MAC subheader are repurposed to carry buffer status information, allowing a single structure to perform both data control and buffer status reporting functions. This multi-functionality improves reporting efficiency without requiring separate dedicated structures.

The patent changes the parameter usage of reserved bits in the MAC subheader from unused/undefined to active buffer status indication. By reassigning the meaning of these reserved bits, the system transforms them into a functional parameter for buffer status reporting. This parameter change allows efficient buffer status indication using existing header space, improving efficiency without adding structural complexity, only semantic reassignment.