SDRAM Row Mapping for DVB-T2 Deinterleaving Bandwidth Limits
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Solution Overview
Problem
Existing deinterleaving apparatus rely on costly SRAM memory due to bandwidth limitations of SDRAM, which is not suitable for deinterleaving applications despite its lower cost potential.
Innovation Solution
A deinterleaving apparatus using SDRAM memory with a row mapper and row deinterleaver configuration that enables burst mode operations, reducing bandwidth requirements and allowing efficient use of SDRAM instead of SRAM, along with an FEC mapper for buffering read commands to optimize SDRAM access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SRAM memory is used for deinterleaving, then bandwidth requirements are met, but cost increases significantly
Solution Approach 1:
The patent changes the data organization parameters within SDRAM to match its burst access characteristics. By reorganizing data in burst-friendly patterns and using row mapper/deinterleaver configurations, the system achieves high bandwidth performance with SDRAM's lower cost, reducing memory cost by 80% while maintaining deinterleaving performance.
Solution Approach 2:
The patent replaces expensive SRAM with cheaper SDRAM for the deinterleaving function. Although SDRAM has inherently lower bandwidth, the patent makes it viable for this application by optimizing data organization and access patterns, achieving cost reduction while maintaining functional requirements.
2Ease of manufacture
If SDRAM memory is used for deinterleving, then cost decreases, but bandwidth limitations prevent adequate performance
Solution Approach 1:
The patent uses a row mapper to pre-organize incoming data into burst-friendly patterns before writing to SDRAM. This preliminary data reorganization ensures that subsequent read operations can efficiently utilize SDRAM's burst mode, maximizing bandwidth utilization and overcoming SDRAM's inherent speed limitations.
Solution Approach 2:
The patent employs dynamic row mapper and deinterleaver configurations that adapt to the specific deinterleving requirements. By dynamically adjusting data organization and access patterns, the system optimizes SDRAM bandwidth utilization and achieves performance comparable to SRAM implementations.
3Ease of operation
If traditional ping-pong deinterleving method is used, then deinterleaving function is achieved, but memory size requirements are high
Solution Approach 1:
The patent segments the deinterleving function into distinct row mapper and deinterleaver stages. This segmentation allows for more efficient memory utilization by processing data in organized blocks, reducing the total memory size required from 19.126 Mbits to 9.625 Mbits while maintaining full deinterleving functionality.
Data Source
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AI summary
The disclosure provides an apparatus for performing deinterleaving of a binary data stream and a DVB-T2 receiver, the apparatus comprising a mapping device and a semiconductor memory, the apparatus comprising a mapping device and a semiconductor memory; said mapping device comprising: an input interface arranged to receive said binary data stream and an output interface arranged to output a deinterleaved instance of said binary data stream; a row mapper, operatively connected to said input interface and said semiconductor memory, said row mapper being configured to group data received through said binary data stream into "write" commands for said semiconductor memory; and a row deinterleaver, operatively connected to said semiconductor memory and said output interface, said row deinterleaver being configured to present deinterleaved data, retrieved from said semiconductor memory by means of "read" commands, to said output interface； wherein said semiconductor memory is an SDRAM memory; and wherein each of said "write" commands is an SDRAM write command for at least part of an SDRAM row, said SDRAM write commands being calculated such that said deinterleaved data can be written to and read out in SDRAM burst mode. By providing a row mapper that acts on the received data stream prior to its storage in the external memory, a data ordering can be achieved that permits the retrieval of deinterleaved data at a reduced bandwidth, in particular by using a burst-read operation on an SDRAM memory.