Overlapped Stream Encoding for Unsynchronized Multi-Receiver Channels
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Solution Overview
Problem
Existing signal transfer methods in wireless networks, such as Gelfand-Pinsker coding, are limited by the need for synchronized encoders and block-based alignment, which restricts achievable information rates and do not optimally exhaust the channel capacity.
Innovation Solution
A signal transfer method involving time-shifted Gelfand-Pinsker coding, where separate streams are encoded with delayed overlap, allowing partial encoding using side-information from the other stream, to achieve high information transfer rates close to channel capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If synchronized block-based encoding is used, then decoding reliability is improved, but information transfer rate is limited
Solution Approach 1:
The patent applies dynamics by allowing the encoding blocks of different streams to have variable time offsets rather than fixed synchronization. The first encoding block from the first stream and the second encoding block from the second stream can overlap in time by a configurable amount, enabling the system to adapt to different channel conditions and rate requirements while maintaining decoding reliability through the receiver's ability to handle unsynchronized blocks.
Solution Approach 2:
The patent applies preliminary action by having the receiver prepare for and compensate for potential time offsets between encoded streams before decoding occurs. The receiver is configured to handle unsynchronized encoding blocks by adjusting its decoding process to account for the time offset, ensuring reliable decoding even when encoding blocks overlap in unsynchronized manners.
2Ease of operation
If orthogonal multiplexing methods are used, then ease of operation is improved, but channel capacity utilization deteriorates
Solution Approach 1:
The patent applies this principle by converting the potentially harmful interference from unsynchronized encoding blocks into a beneficial resource for increasing channel capacity. Instead of avoiding overlap through orthogonal scheduling, the system allows encoding blocks to overlap in time and uses the receiver's ability to handle unsynchronized blocks to extract more information from the channel, thereby converting what would be interference into useful signal diversity.
3Productivity
If time-shifted encoding with overlap is used, then information transfer rate is improved, but decoding complexity increases
Solution Approach 1:
The patent applies this principle by introducing an intermediary processing step at the receiver that handles the time-offset compensation between unsynchronized encoding blocks. The receiver uses channel state information and time offset estimates as intermediaries to align and properly decode the overlapping encoded blocks, managing the increased complexity through structured intermediate processing rather than direct complex decoding.
Data Source
Figure 1~2
AI summary
The invention concerns a signal transfer method for the transmission and reception of encoded signals between at least one sender and multiple receivers over a common communication channel, the method comprising the following steps: providing at least two separate streams, namely at least a first stream and a second stream, of information to be encoded and simultaneously transmitted over the channel by the sender, wherein the first stream is for a first receiver and comprises at least one first stream-block (m1) and the second stream is for a second receiver and comprises at least one second stream-block (m2); encoding at least the first stream as a first signal (u) and the second stream as a second signal (v) and transmitting an addition of the first signal (u) with the second signal (v) over the channel; wherein: encoding of the first stream (all m1) is delayed with respect to encoding the second stream, wherein at least one first stream-block (m1) of the first stream and at least one second stream-block (m2) of the second stream at least partially time-overlap, which is defined as overlap with respect to time; wherein one second stream-block (m2) of the second stream is encoded to be a second block-code using a first coding method; and after said second stream-block (m2) is encoded, encoding one first stream-block (m1) of the first stream using, at least partially, a dirty-paper-coding method. The invention further concerns a sender (100) configured to perform the signal transfer method.