Hierarchical Coding with Multiple Antennas for Broadcast Adaptability
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Solution Overview
Problem
Current wireless communication systems lack effective techniques for performing hierarchical coding with multiple antennas, which is necessary to improve broadcast services by adapting to different channel conditions and signal-to-noise ratios (SNRs) of users in a multi-antenna environment.
Innovation Solution
The techniques involve coding and modulating base and enhancement streams separately and processing them using spatial processing schemes like transmit diversity and spatial multiplexing, and combining them for transmission from multiple antennas, allowing receivers to recover streams using time division multiplexing or superposition methods, depending on the channel conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If hierarchical coding is implemented using non-uniform modulation in a SISO system, then users with different channel conditions can recover data at different rates, but the system cannot provide diversity against path effects or improve transmission capacity
Solution Approach 1:
The patent transitions from a single-antenna SISO system to multi-antenna MISO, SIMO, or MIMO systems, adding the spatial dimension to hierarchical coding. This allows the system to maintain adaptability to different channel conditions while simultaneously providing diversity against path effects and improving transmission capacity through multiple spatial paths.
Solution Approach 2:
The patent segments the transmitted signal into multiple spatial streams from multiple antennas, where each antenna or antenna combination can be optimized for different users' channel conditions. This segmentation enables both adaptability to individual user conditions and diversity through multiple independent spatial paths.
2Reliability
If multiple antennas are used to provide diversity and improve transmission capacity, then reliability and throughput increase, but the complexity of performing hierarchical coding with multiple antennas becomes significant
Solution Approach 1:
The patent segments the hierarchical coding process into distinct spatial processing stages: base stream encoding, enhancement stream encoding, spatial multiplexing or transmit diversity processing, and combination at the receiver. This segmentation makes the complex multi-antenna hierarchical coding manageable by breaking it into modular, independently processable components.
Solution Approach 2:
The patent employs dynamic spatial processing where the receiver adapts its processing method (time division multiplexing or superposition) based on channel conditions and user requirements. This dynamic approach optimizes performance while managing complexity by selecting appropriate processing modes rather than implementing all possible processing chains simultaneously.
3Adaptability or versatility
If the base stream is transmitted to all users in the broadcast area, then universal coverage is achieved, but the data rate is limited by the user with the worst channel conditions
Solution Approach 1:
The patent segments the broadcast data into two distinct streams: a base stream transmitted to all users for universal coverage, and an enhancement stream transmitted at higher rates for users with better channel conditions. This segmentation allows the system to maintain broad coverage while simultaneously achieving high data rates for capable users, resolving the contradiction between coverage and productivity.
Solution Approach 2:
The patent applies local quality by transmitting the enhancement stream with higher quality (higher data rate) to specific users who experience better channel conditions, while maintaining base stream transmission to all users. This allows different parts of the user base to receive data at appropriate quality levels based on their local channel conditions.
Data Source
AI summary
Techniques are provided for performing hierarchical coding in a multi-antenna communication system (e.g., a SIMO, MISO, or MIMO system). At a transmitter, a base stream and an enhancement stream are coded and modulated separately to obtain first and second data symbol streams, respectively. The first data symbol stream is processed in accordance with a first spatial processing scheme (e.g., a transmit diversity or a spatial multiplexing scheme) to obtain a first set of symbol substreams. The second data symbol stream is processed in accordance with a second spatial processing scheme (e.g., transmit diversity or spatial multiplexing) to obtain a second set of symbol substreams. The first set of symbol substreams is combined (e.g., using time division multiplexing or superposition) with the second set of symbol substreams to obtain multiple transmit symbol streams for transmission from multiple transmit antennas. A receiver performs complementary processing to recover the base stream and enhancement stream.