Partitioned Bluetooth Protocol Stack for Reduced On-Chip Memory
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Solution Overview
Problem
The high cost of Bluetooth enabled systems is attributed to the significant on-chip ROM and RAM usage by the Bluetooth transceiver chip, which is necessary for storing and executing the Bluetooth protocol stack, particularly due to the firmware requirements across various layers.
Innovation Solution
The Bluetooth protocol stack is partitioned such that a larger portion is executed by the host processing system instead of the Bluetooth transceiver, reducing on-chip ROM and RAM usage by moving layers with low real-time requirements to external memory, thereby reducing the size and cost of the Bluetooth enabled system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the Bluetooth protocol stack is stored in on-chip ROM and RAM of the Bluetooth transceiver chip, then the transceiver can execute the protocol stack locally, but the cost of the system increases significantly
Solution Approach 1:
The Bluetooth protocol stack is divided into two segments: a first portion stored in on-chip ROM/RAM of the Bluetooth transceiver chip for critical real-time functions, and a second portion stored in external memory of the host processing system for less time-sensitive functions. This segmentation allows the system to maintain reliable local execution of time-critical protocol functions while reducing on-chip memory requirements to lower cost.
Solution Approach 2:
The second portion of the Bluetooth protocol stack is extracted from the Bluetooth transceiver chip and relocated to external memory in the host processing system. This extraction reduces the on-chip ROM and RAM requirements of the Bluetooth transceiver, thereby reducing the overall system cost while maintaining functional equivalence through the host processor's execution of the extracted protocol portion.
2Ease of manufacture
If a larger portion of the Bluetooth protocol stack is executed by the host processing system, then on-chip ROM and RAM usage by the Bluetooth transceiver is reduced, but the host processing system must handle additional real-time requirements
Solution Approach 1:
Different quality levels of execution are assigned to different portions of the protocol stack based on real-time requirements. The first portion requiring strict real-time performance is maintained on the Bluetooth transceiver chip with guaranteed execution characteristics, while the second portion with more flexible timing requirements is moved to the host processing system. This local quality differentiation optimizes the trade-off between memory requirements and execution performance.
Data Source
AI summary
A system includes a first memory, a second memory, a host processor, and a second processor. The first memory is configured to store first layers of a Bluetooth protocol stack including at least a portion of a link manager layer. The second memory is configured to store second layers of the Bluetooth protocol stack. The second layers have higher real-time requirements than the first layers. The host processor is coupled to the first memory. The host processor is configured to execute the first layers. The second processor is coupled to the second memory. The second processor is configured to execute the second layers.