Handoffs in User-Centric Cell-Free MIMO Networks: A POMDP Framework

Fuente: arXiv
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Main Authors: Ammar, Hussein A., Adve, Raviraj, Shahbazpanahi, Shahram, Boudreau, Gary, Srinivas, Kothapalli Venkata
Format: Preprint
Published: 2024
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author Ammar, Hussein A.
Adve, Raviraj
Shahbazpanahi, Shahram
Boudreau, Gary
Srinivas, Kothapalli Venkata
author_facet Ammar, Hussein A.
Adve, Raviraj
Shahbazpanahi, Shahram
Boudreau, Gary
Srinivas, Kothapalli Venkata
contents We study the problem of managing handoffs (HOs) in user-centric cell-free massive MIMO (UC-mMIMO) networks. Motivated by the importance of controlling the number of HOs and by the correlation between efficient HO decisions and the temporal evolution of the channel conditions, we formulate a partially observable Markov decision process (POMDP) with the state space representing the discrete versions of the large-scale fading and the action space representing the association decisions of the user with the access points (APs). We develop a novel algorithm that employs this model to derive a HO policy for a mobile user based on current and future rewards. To alleviate the high complexity of our POMDP, we follow a divide-and-conquer approach by breaking down the POMDP formulation into sub-problems, each solved separately. Then, the policy and the candidate pool of APs for the sub-problem that produced the best total expected reward are used to perform HOs within a specific time horizon. We then introduce modifications to our algorithm to decrease the number of HOs. The results show that half of the number of HOs in the UC-mMIMO networks can be eliminated. Namely, our novel solution can control the number of HOs while maintaining a rate guarantee, where a 47%-70% reduction of the cumulative number of HOs is observed in networks with a density of 125 APs per km2. Most importantly, our results show that a POMDP-based HO scheme is promising to control HOs.
format Preprint
id arxiv_https___arxiv_org_abs_2403_08900
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Handoffs in User-Centric Cell-Free MIMO Networks: A POMDP Framework
Ammar, Hussein A.
Adve, Raviraj
Shahbazpanahi, Shahram
Boudreau, Gary
Srinivas, Kothapalli Venkata
Information Theory
Distributed, Parallel, and Cluster Computing
Networking and Internet Architecture
Systems and Control
Signal Processing
We study the problem of managing handoffs (HOs) in user-centric cell-free massive MIMO (UC-mMIMO) networks. Motivated by the importance of controlling the number of HOs and by the correlation between efficient HO decisions and the temporal evolution of the channel conditions, we formulate a partially observable Markov decision process (POMDP) with the state space representing the discrete versions of the large-scale fading and the action space representing the association decisions of the user with the access points (APs). We develop a novel algorithm that employs this model to derive a HO policy for a mobile user based on current and future rewards. To alleviate the high complexity of our POMDP, we follow a divide-and-conquer approach by breaking down the POMDP formulation into sub-problems, each solved separately. Then, the policy and the candidate pool of APs for the sub-problem that produced the best total expected reward are used to perform HOs within a specific time horizon. We then introduce modifications to our algorithm to decrease the number of HOs. The results show that half of the number of HOs in the UC-mMIMO networks can be eliminated. Namely, our novel solution can control the number of HOs while maintaining a rate guarantee, where a 47%-70% reduction of the cumulative number of HOs is observed in networks with a density of 125 APs per km2. Most importantly, our results show that a POMDP-based HO scheme is promising to control HOs.
title Handoffs in User-Centric Cell-Free MIMO Networks: A POMDP Framework
topic Information Theory
Distributed, Parallel, and Cluster Computing
Networking and Internet Architecture
Systems and Control
Signal Processing
url https://arxiv.org/abs/2403.08900