MAC Subheader LCID Extension for IAB Networks
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Solution Overview
Problem
Current communication systems face limitations in extending the logical channel identity (LCID) space within media access control (MAC) protocol data units (PDUs), particularly in integrated access backhaul (IAB) networks, where the number of logical channels is insufficient for handling multiple user equipment (UE) connections, leading to a need for enhanced LCID extension.
Innovation Solution
The introduction of a second logical channel identity (LCID) field within the MAC subheader, indicated by a specific indicator, which can occupy additional bits or redefined reserved bits, allowing for an extended LCID value range, enabling increased logical channel support in IAB networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the existing LCID field structure is used in MAC subheader, then the MAC PDU format remains simple and compatible with existing systems, but the number of supported logical channels is insufficient for multiple UE connections in IAB networks
Solution Approach 1:
The LCID field is segmented into two separate fields: a first LCID field that remains in the MAC subheader for backward compatibility, and a second LCID field that is added separately to extend the identification capability. This segmentation allows the system to maintain simplicity for existing applications while adding extended functionality for multiple UE connections without requiring a complete redesign of the MAC subheader structure.
Solution Approach 2:
The patent extends the LCID identification capability by adding another dimension - a second LCID field that operates alongside the first LCID field. This dimensional expansion allows the system to represent more logical channels by combining both fields, effectively increasing the address space from 64 channels to 128 channels without fundamentally changing the basic MAC subheader format.
2Adaptability or versatility
If a second LCID field is added to extend LCID space, then the number of logical channels increases to support more UE connections, but the MAC subheader size increases
Solution Approach 1:
The second LCID field is added locally only where needed - specifically in the MAC subheader of MAC PDUs that require extended LCID identification. This local addition allows the system to maintain compact subheader length for most common cases (using only the first LCID field) while providing extended capability when necessary, thus balancing the trade-off between LCID space extension and subheader length.
Solution Approach 2:
Instead of uniformly increasing the LCID field size throughout the entire MAC subheader, the patent applies a partial action by adding only a second LCID field with specific predefined values (0 and 1) at strategic positions. This partial extension provides sufficient LCID space for multiple UE connections without excessively increasing the overall subheader length, achieving the minimum necessary extension rather than maximum possible extension.
3Adaptability or versatility
If reserved bits are redefined as indicator fields to indicate second LCID field presence, then the MAC subheader structure becomes more flexible, but the interpretation complexity increases
Solution Approach 1:
The patent introduces an intermediary indicator field that serves as a mediator between the receiver and the second LCID field. This indicator field, formed by redefining reserved bits, acts as a signal that tells the receiver whether to interpret the subsequent bits as part of the extended LCID identification or as padding/other fields. This intermediary mechanism simplifies the receiver's task by providing a clear binary indicator (present/absent) rather than requiring complex contextual analysis to determine where the extended LCID field begins and ends.
Data Source
AI summary
Methods, a transmitter device and a receiver device are provided for communication of media access control (MAC) protocol data unit (PDU). According to an embodiment, the transmitter device determines an MAC PDU including an MAC subheader and transmits the MAC PDU to a receiver device. The MAC subheader includes a second logical channel identity (LCID) field which is an extension of a first LCID field. A presence of the second LCID field is indicated by an indicator that is included in the MAC subheader.