Real-time traffic in a cellular network varies over time and often shows tidal patterns, such as the day/night traffic pattern. With this characteristic, we can reduce the energy consumption of a cellular network by consolidating workloads spreading over the entire network to fewer Base Stations (BSs). In this work, we propose a BS sleeping strategy for a two-tier Heterogeneous Cellular Network (HeCN) that consists of Macro Base Stations (MaBS) and Micro Base Stations (MiBS). We first use a Bidirectional Long Short-Term Memory (BLSTM) neural network to predict the future traffic of each user. Based on the predicted traffic, our proposed BS sleeping strategy switches user connections from underutilized MiBSs to other BSs, then switches off the idle MiBSs. The MaBSs are never switched off. All user connections have predefined Signal-to-Interference-plus-Noise Ratio thresholds, and we ensure that each user’s service quality, which is related to the user’s traffic demand rate, is not degraded when switching user connections. We demonstrate the effectiveness and superiority of our proposed strategy over four other baselines through extensive numerical simulations, where our proposed strategy substantially outperforms the four baselines in different scenarios.
{"title":"A Base Station Sleeping Strategy in Heterogeneous Cellular Networks Based on User Traffic Prediction","authors":"Xinyu Wang;Bingchen Lyu;Chao Guo;Jiahe Xu;Moshe Zukerman","doi":"10.1109/TGCN.2023.3324486","DOIUrl":"10.1109/TGCN.2023.3324486","url":null,"abstract":"Real-time traffic in a cellular network varies over time and often shows tidal patterns, such as the day/night traffic pattern. With this characteristic, we can reduce the energy consumption of a cellular network by consolidating workloads spreading over the entire network to fewer Base Stations (BSs). In this work, we propose a BS sleeping strategy for a two-tier Heterogeneous Cellular Network (HeCN) that consists of Macro Base Stations (MaBS) and Micro Base Stations (MiBS). We first use a Bidirectional Long Short-Term Memory (BLSTM) neural network to predict the future traffic of each user. Based on the predicted traffic, our proposed BS sleeping strategy switches user connections from underutilized MiBSs to other BSs, then switches off the idle MiBSs. The MaBSs are never switched off. All user connections have predefined Signal-to-Interference-plus-Noise Ratio thresholds, and we ensure that each user’s service quality, which is related to the user’s traffic demand rate, is not degraded when switching user connections. We demonstrate the effectiveness and superiority of our proposed strategy over four other baselines through extensive numerical simulations, where our proposed strategy substantially outperforms the four baselines in different scenarios.","PeriodicalId":13052,"journal":{"name":"IEEE Transactions on Green Communications and Networking","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2023-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136303585","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-13DOI: 10.1109/TGCN.2023.3324205
Yang Lu;Ming-Min Zhao;Ming Lei;Min-Jian Zhao
Due to the sequential nature of the successive-cancellation (SC) algorithm, the decoding of polar codes suffers from significant decoding latencies, which hinders its application in low-latency communication scenarios. Fast SC decoding is able to speed up the SC decoding process, by implementing parallel decoders at the intermediate levels of the SC decoding tree for some special polar constituent subcodes (special nodes) with specific information and frozen bit patterns. To further improve the parallelism of SC decoding, this paper presents a new class of special nodes composed of a sequence of rate one or single-parity-check (SR1/SPC) nodes, which can be easily found especially in high-rate polar code and is able to envelop a wide variety of existing special node types. Then, we analyse the parity constraints caused by the frozen bits in each descendant node, such that the estimated codeword of the SR1/SPC node can keep its validity once the parity constraints are satisfied. Inspired by maximum-likelihood (ML) decoding, a generalized fast decoding algorithm is finally proposed to decode SR1/SPC nodes efficiently, which is able to guarantee that all the parity constraints are satisfied. Simulation results show that some SR1/SPC nodes can be decoded with quasi-ML performance, and the overall decoding latency can be reduced by up to 43.8% with slight performance improvement, as compared to the state-of-the-art fast SC decoder.
{"title":"Fast Successive-Cancellation Decoding of Polar Codes With Sequence Nodes","authors":"Yang Lu;Ming-Min Zhao;Ming Lei;Min-Jian Zhao","doi":"10.1109/TGCN.2023.3324205","DOIUrl":"10.1109/TGCN.2023.3324205","url":null,"abstract":"Due to the sequential nature of the successive-cancellation (SC) algorithm, the decoding of polar codes suffers from significant decoding latencies, which hinders its application in low-latency communication scenarios. Fast SC decoding is able to speed up the SC decoding process, by implementing parallel decoders at the intermediate levels of the SC decoding tree for some special polar constituent subcodes (special nodes) with specific information and frozen bit patterns. To further improve the parallelism of SC decoding, this paper presents a new class of special nodes composed of a sequence of rate one or single-parity-check (SR1/SPC) nodes, which can be easily found especially in high-rate polar code and is able to envelop a wide variety of existing special node types. Then, we analyse the parity constraints caused by the frozen bits in each descendant node, such that the estimated codeword of the SR1/SPC node can keep its validity once the parity constraints are satisfied. Inspired by maximum-likelihood (ML) decoding, a generalized fast decoding algorithm is finally proposed to decode SR1/SPC nodes efficiently, which is able to guarantee that all the parity constraints are satisfied. Simulation results show that some SR1/SPC nodes can be decoded with quasi-ML performance, and the overall decoding latency can be reduced by up to 43.8% with slight performance improvement, as compared to the state-of-the-art fast SC decoder.","PeriodicalId":13052,"journal":{"name":"IEEE Transactions on Green Communications and Networking","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2023-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136305811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-06DOI: 10.1109/TGCN.2023.3322539
Yijun Piao;Tae-Jin Lee
Since massive number of User Equipment (UE)s will cause more collisions and increase delay, improved Random Access (RA) methods have been researched and proposed. With the introduction of the new two step RA procedure in 3rd Generation Partnership Project (3GPP) Release 16, the average RA delay of UE could be further reduced. To further enhance two step RA in association with four step RA, we propose a new RA method that integrates four step RA and two step RA for heterogeneous IoT devices, so that UEs can perform two types of RA methods in parallel. With the proposed method, we aim to minimize the UE conflicts with the available RA resources, increasing the efficiency of RA and decreasing the average RA delay. We optimize the probability of two step RA in the proposed method and present algorithm to provide the optimal resource configuration and parameter settings in the RA procedure according to the RA status of UEs. A Markov chain model is formulated to analyze and confirm the effectiveness of the proposed RA method. As a result of extensive simulations, we present that the proposed RA method can enhance the property of the RA procedure for massive and heterogeneous devices access scenarios in 5G and 6G communications.
由于大量的用户设备(UE)会导致更多的碰撞并增加延迟,因此人们研究并提出了改进的随机接入(RA)方法。随着第三代合作伙伴计划(3GPP)第 16 版引入新的两步 RA 程序,UE 的平均 RA 时延可进一步降低。为了进一步加强两步 RA 与四步 RA 的结合,我们针对异构物联网设备提出了一种整合了四步 RA 和两步 RA 的新 RA 方法,使 UE 可以并行执行两种 RA 方法。通过所提出的方法,我们旨在最大限度地减少 UE 与可用 RA 资源的冲突,从而提高 RA 的效率并降低 RA 的平均延迟。我们优化了所提方法中两步 RA 的概率,并提出了一种算法,可根据 UE 的 RA 状态在 RA 过程中提供最优资源配置和参数设置。建立了马尔可夫链模型来分析和确认拟议 RA 方法的有效性。通过大量仿真,我们发现所提出的 RA 方法可以增强 5G 和 6G 通信中大规模和异构设备接入场景下 RA 程序的性能。
{"title":"Integrated 2–4 Step Random Access for Heterogeneous and Massive IoT Devices","authors":"Yijun Piao;Tae-Jin Lee","doi":"10.1109/TGCN.2023.3322539","DOIUrl":"10.1109/TGCN.2023.3322539","url":null,"abstract":"Since massive number of User Equipment (UE)s will cause more collisions and increase delay, improved Random Access (RA) methods have been researched and proposed. With the introduction of the new two step RA procedure in 3rd Generation Partnership Project (3GPP) Release 16, the average RA delay of UE could be further reduced. To further enhance two step RA in association with four step RA, we propose a new RA method that integrates four step RA and two step RA for heterogeneous IoT devices, so that UEs can perform two types of RA methods in parallel. With the proposed method, we aim to minimize the UE conflicts with the available RA resources, increasing the efficiency of RA and decreasing the average RA delay. We optimize the probability of two step RA in the proposed method and present algorithm to provide the optimal resource configuration and parameter settings in the RA procedure according to the RA status of UEs. A Markov chain model is formulated to analyze and confirm the effectiveness of the proposed RA method. As a result of extensive simulations, we present that the proposed RA method can enhance the property of the RA procedure for massive and heterogeneous devices access scenarios in 5G and 6G communications.","PeriodicalId":13052,"journal":{"name":"IEEE Transactions on Green Communications and Networking","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2023-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136008107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}