Reconfigurable Data Word Mapping Circuit for Multi-Protocol CPRI Frames
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Solution Overview
Problem
Conventional mapping circuits in cellular telephony systems, such as those using the CPRI standard, lack flexibility to accommodate varying IQ sample sizes and CPRI basic frame word lengths across different wireless services, requiring hardware reconfiguration for each protocol, which is costly and inefficient.
Innovation Solution
A reconfigurable mapping and de-mapping circuit using a shift register chain and multiplexers, with address signals stored in memory, allowing for flexible mapping and de-mapping of IQ data into CPRI basic frames without hardware changes, accommodating different IQ sample sizes and frame lengths by reprogramming control words.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional mapping circuits are used for each wireless service protocol, then mapping functionality is provided, but hardware reconfiguration is required for each protocol which increases manufacturing costs and device complexity
Solution Approach 1:
The patent implements a universal mapping circuit that can handle multiple wireless service protocols (WCDMA, WiMAX, LTE, etc.) through a single hardware design. The circuit uses reconfigurable parameters including sample width, AXC bandwidth, and CPRI line rate to adapt to different protocols without requiring physical hardware changes, thus achieving multi-functionality while reducing device complexity
Solution Approach 2:
The mapping circuit achieves protocol adaptability by dynamically changing operational parameters such as sample width (number of bits for IQ data words), AXC bandwidth, and CPRI line rate. These parameter changes allow the same hardware circuit to be reconfigured for different wireless services through software or control logic rather than hardware modification
2Reliability
If different mapping implementations are developed for each wireless service, then specific protocol requirements are met, but manufacturing costs increase due to lack of standardization
Solution Approach 1:
The patent creates a standardized universal mapping circuit design that can serve multiple wireless service protocols. This standardization allows equipment providers to manufacture a single type of mapping circuit that reliably supports WCDMA, WiMAX, LTE and other protocols, thereby reducing manufacturing costs through economies of scale while maintaining protocol-specific performance requirements
3Ease of manufacture
If base stations are located remotely from antennas using CPRI, then real estate costs are reduced, but mapping flexibility is required to accommodate varying IQ sample sizes and frame lengths
Solution Approach 1:
The mapping circuit supports remote base station deployment by enabling dynamic parameter changes to accommodate different IQ sample sizes (4-20 bits for uplink, 8-20 bits for downlink in LTE) and varying CPRI line rates. This flexibility allows the system to adapt to different deployment scenarios and service requirements while maintaining the cost benefits of remote positioning
Data Source
AI summary
A de-mapping circuit for de-mapping input words of a first length into output words of a second length different from the first length. In one embodiment, the circuit includes a word register of the first length and temporary registers of the second length. The word register successively stores each of the inputs words in response to cycles of a clock. The temporary registers temporarily store the output words. Multiplexers configured by address signals select bits from stored input words and store the selected bits into the temporary registers to form temporarily stored output words.