Modular Hypernetworks for Scalable and Adaptive Deep MIMO Receivers
Tomer Raviv, Nir Shlezinger
TL;DR
This work tackles the rigidity of static DNN-based deep receivers in dynamic uplink MIMO systems where the number of users $K[t]$ and channel conditions vary. It introduces modular hypernetworks that generate per-user module weights $\{\boldsymbol{\theta}^{(k)}[t]\}$ conditioned on fixed-size embeddings $\boldsymbol{u}^{\text{user}}_k[t]$, enabling the architecture to adapt its complexity as $K[t]$ changes without on-device retraining. Offline training over diverse channel conditions enables rapid on-the-fly adaptation during deployment, with complexity savings compared to online retraining while maintaining near-online performance. The approach offers a scalable, low-latency solution for adaptive deep receivers in mobile networks, balancing accuracy, flexibility, and computational budget.
Abstract
Deep neural networks (DNNs) were shown to facilitate the operation of uplink multiple-input multiple-output (MIMO) receivers, with emerging architectures augmenting modules of classic receiver processing. Current designs consider static DNNs, whose architecture is fixed and weights are pre-trained. This induces a notable challenge, as the resulting MIMO receiver is suitable for a given configuration, i.e., channel distribution and number of users, while in practice these parameters change frequently with network variations and users leaving and joining the network. In this work, we tackle this core challenge of DNN-aided MIMO receivers. We build upon the concept of hypernetworks, augmenting the receiver with a pre-trained deep model whose purpose is to update the weights of the DNN-aided receiver upon instantaneous channel variations. We design our hypernetwork to augment modular deep receivers, leveraging their modularity to have the hypernetwork adapt not only the weights, but also the architecture. Our modular hypernetwork leads to a DNN-aided receiver whose architecture and resulting complexity adapts to the number of users, in addition to channel variations, without retraining. Our numerical studies demonstrate superior error-rate performance of modular hypernetworks in time-varying channels compared to static pre-trained receivers, while providing rapid adaptivity and scalability to network variations.
