Enhancing Perceptual Quality of Wireless Image Transmission Using Diffusion-Aided Joint Source-Channel Coding

Core Concepts

The proposed DiffJSCC framework leverages pre-trained text-to-image diffusion models to significantly enhance the perceptual quality of images transmitted over wireless channels, especially under poor channel conditions and limited bandwidth.

Abstract

The paper introduces DiffJSCC, a novel framework that combines deep joint source-channel coding (deep JSCC) with the Stable Diffusion model to improve the perceptual quality of wireless image transmission.
Key highlights:

Current deep JSCC approaches focus on minimizing standard distortion metrics like MSE, which do not necessarily translate to better perceptual quality.
DiffJSCC uses the initial deep JSCC reconstruction as a starting point and then applies the Stable Diffusion model to enhance the perceptual quality.
The framework extracts spatial and textual features from the initial reconstruction, which are then used to fine-tune the Stable Diffusion model's control module. This allows the denoising process to be guided by the initial reconstruction without being directly influenced by its distortion.
Experiments on the Kodak dataset show that DiffJSCC significantly outperforms conventional separate schemes and prior deep JSCC approaches in terms of perceptual metrics like LPIPS and FID, especially under poor channel conditions and limited bandwidth.
DiffJSCC can achieve highly realistic reconstructions for 768x512 pixel Kodak images with only 3072 symbols (<0.008 symbols per pixel) under 1dB SNR.

Stats

The transmission rate R is quantified by channel per pixel (cpp), which is defined as: R = K/HW cpp.
The channel SNR γ is computed as γ = P/σ^2 where P denotes the power of the transmitted signal and σ^2 is the power of the channel noise.

Quotes

"Experiments on the Kodak dataset show that the proposed method significantly surpasses both conventional methods and prior deep JSCC approaches on perceptual metrics such as LPIPS and FID scores, especially with poor channel conditions and limited bandwidth."
"Notably, DiffJSCC can achieve highly realistic reconstructions for 768×512 pixel Kodak images with only 3072 symbols (<0.008 symbols per pixel) under 1dB SNR."

Key Insights Distilled From

Diffusion-Aided Joint Source Channel Coding For High Realism Wireless Image Transmission

by Mingyu Yang,... at arxiv.org 04-30-2024

https://arxiv.org/pdf/2404.17736.pdf

Deeper Inquiries

How can the DiffJSCC framework be extended to handle more complex channel models beyond AWGN, such as fading or interference-limited channels?

To extend the DiffJSCC framework to handle more complex channel models, such as fading or interference-limited channels, several modifications and enhancements can be implemented:

Channel Modeling: Integrate channel models that accurately represent fading or interference effects. This could involve incorporating Rayleigh or Rician fading models, as well as models for interference from other sources in the environment.

Adaptive Encoding: Develop adaptive encoding and decoding schemes that can dynamically adjust to the varying channel conditions. This could involve using reinforcement learning techniques to optimize the encoding and decoding process based on real-time channel feedback.

Diversity Techniques: Implement diversity techniques such as space diversity, time diversity, or frequency diversity to combat fading effects. This could involve transmitting redundant information through multiple paths or frequencies to improve reliability.

Error Correction Coding: Enhance the error correction coding schemes to be more robust against fading and interference. This could include using advanced coding techniques like turbo codes or LDPC codes optimized for specific channel conditions.

Feedback Mechanisms: Incorporate feedback mechanisms between the transmitter and receiver to adapt the encoding and decoding strategies based on the channel state information. This feedback loop can help optimize the transmission process for varying channel conditions.

By incorporating these strategies, the DiffJSCC framework can be extended to handle more complex channel models beyond AWGN, enabling robust and reliable image transmission in challenging wireless environments.

How can the DiffJSCC framework be adapted to handle video transmission, where the temporal correlation between frames could be exploited to improve the overall quality?

Adapting the DiffJSCC framework for video transmission involves leveraging the temporal correlation between frames to enhance the overall quality. Here are some key strategies to adapt DiffJSCC for video transmission:

Temporal Compression: Exploit the temporal redundancy in video sequences by incorporating motion estimation and compensation techniques. This can help reduce the amount of information that needs to be transmitted for consecutive frames.

Grouping Frames: Group frames into hierarchical structures such as GOPs (Group of Pictures) to optimize the encoding process. By considering the dependencies between frames within a group, more efficient compression and transmission strategies can be applied.

Predictive Coding: Implement predictive coding schemes where the current frame is predicted based on previous frames. By transmitting only the prediction error, the amount of data to be transmitted can be reduced, leading to higher compression ratios.

Adaptive Rate Control: Develop adaptive rate control mechanisms that can dynamically allocate bits based on the complexity of each frame. This ensures that more bits are allocated to critical frames with high motion or detail, improving overall video quality.

Buffer Management: Introduce buffer management techniques to handle delays and ensure smooth playback. By optimizing the buffer size and transmission rate, the system can maintain a balance between latency and video quality.

By incorporating these techniques, the DiffJSCC framework can be tailored to effectively handle video transmission, exploiting temporal correlations to achieve efficient and high-quality video delivery over wireless channels.