PAN Field TBF Addressing via PCS Masking in GSM/EDGE
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Solution Overview
Problem
In GSM/EDGE radio access networks, existing methods for reducing latency in ACK/NACK reporting require dedicated bits to identify the Temporary Block Flow (TBF) in the PAN field, which is inefficient.
Innovation Solution
A PAN check sequence (PCS) is created using cyclic redundancy check (CRC) encoding and masked with a Temporary Flow Identity (TFI), allowing the TFI to be transmitted without explicit bits, using masking techniques such as modulo-2 addition or (M, N) code conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dedicated bits are used to identify TBF in the PAN field, then TBF identification is reliable, but transmission overhead increases
Solution Approach 1:
The patent merges the TBF identification function with the existing PAN check sequence by masking the PCS with the TFI. Instead of adding separate dedicated bits for TBF identification, the TFI is embedded into the PCS bits through bitwise masking operations, combining two functions (error detection and TBF identification) into a single field
Solution Approach 2:
The PAN check sequence is given multi-functionality: it continues to serve its original purpose of error detection while simultaneously carrying TBF identification information through the masking mechanism. The same PCS bits perform dual roles, eliminating the need for separate dedicated identification bits
2Measurement precision
If explicit bits are allocated for TBF identity in PAN field, then TBF addressing is accurate, but latency reduction efficiency decreases
Solution Approach 1:
The patent combines TBF identification with the PAN field's existing check sequence, eliminating the need for separate explicit bits. This merging reduces the total number of bits transmitted in the PAN field, directly improving latency reduction efficiency while maintaining accurate TBF addressing through the masking mechanism
3Quantity of substance
If TFI is transmitted using masking with PCS, then overhead is reduced, but complexity of processing increases
Solution Approach 1:
The masking operation is performed in advance during the creation of the PAN field, before transmission. The TFI is pre-masked with the PCS to create the final PAN field content, so that receiving entities can simply perform the corresponding unmasking operation without complex processing during real-time communication
Solution Approach 2:
The masking operation acts as an intermediary transformation that converts the TFI into a form that can be embedded in the PCS. This intermediary step (masking) simplifies the overall process by providing a straightforward mathematical operation (bitwise AND) that is easier to implement than alternative approaches
Data Source
AI summary
A method and apparatus for indicating a temporary block flow (TBF) to which a piggybacked acknowledgement/non-acknowledgement (PAN) field is addressed. A PAN check sequence (PCS) is created, for example using a cyclic redundancy check (CRC) encoding. The PCS is masked with a temporary flow identity (TFI) assigned to a TBF or a mask generated based on the TFI. A data block including the PAN field and the masked PCS is then processed for transmission. The mask may be generated by converting the TFI using an (M, N) code, M being not greater than the number of bits of the PCS and N being the number of bits of the TFI. With this scheme, a TFI may be transmitted in a PAN field without using explicit bits to identify the TBF.