Energy-Efficient Matching for Resource Allocation in D2D Enabled Cellular Networks

Energy-efficiency (EE) is critical for device-to-device (D2D) enabled cellular networks due to limited battery capacity and severe co-channel interference. In this paper, we address the EE optimization problem by adopting a stable matching approach. The NP-hard joint resource allocation problem is formulated as a one-to-one matching problem under two-sided preferences, which vary dynamically with channel states and interference levels. A game-theoretic approach is employed to analyze the interactions and correlations among user equipments (UEs), and an iterative power allocation algorithm is developed to establish mutual preferences based on nonlinear fractional programming. We then employ the Gale-Shapley (GS) algorithm to match D2D pairs with cellular UEs (CUs), which is proved to be stable and weak Pareto optimal. We provide a theoretical analysis and description for implementation details and algorithmic complexity. We also extend the algorithm to address scalability issues in large-scale networks by developing tie-breaking and preference deletion based matching rules. Simulation results validate the theoretical analysis and demonstrate that significant performance gains of average EE and matching satisfactions can be achieved by the proposed algorithm

Joint space-frequency block codes and signal alignment for heterogeneous networks

In this paper, we propose a new diversity-oriented space-frequency block codes (SFBC) and signal alignment (SA) enabled physical network coding (PNC) method for the uplink of heterogeneous networks. The proposed joint Dual-SFBC with SA-PNC design substantially reduces interference and enables connecting a larger number of users when compared with methods adopting interference alignment (IA) or PNC. The main motivation behind the dual SFBC and SA-PNC design is that it allows the efficient coexistence of macro and small cells without any inter-system channel information requirements. Numerical results also verify that the proposed method outperforms the existing SA-PNC static method without any additional information exchange requirement between the two systems while achieving the main benefits of IA and SA-PNC coordinated methods recently proposed.publishe

Efficient radio resource allocation for Device-to-Device communication

Využití Device-to-Device komunikace v bezdrátových sítích umožňuje přímou komunikaci mezi dvěma zařízeními, které se nachází v blízkosti sebe a využívají spektrum určené primárně pro běžné mobilní uživatele k navýšení kapacity sítě a k lepšímu využití spektra. Použití Device-to-Device komunikace v mobilní síti vede k určitým výzvám jako je například rušení běžných mobilních uživatelů s uživateli využívající komunikaci Device-to-Device. Správné využívání radiových zdrojů, výběr dostupných modů pro Device-to-Device komunikaci a alokování výkonu pro Device-to-Device zařízení v síti vede ke zvýšení celkové propustnosti systému. Navrhované metody maximalizují celkovou propustnost sítě pro běžné mobilní uživatele za garantovaných služeb a omezení rušení od Device-to-Device uživatelů. Tyto podmínky vedou ke zvyšující se komplexitě výpočtu s rostoucím počtem uživatelů. Navrhované metody alokování spektra jsou blízké k optimálním při užití přiměřené výpočetní komplexity.Device-to-Device communication in the cellular networks allows direct transmission between devices in each other's proximity that reuse the cellular spectrum intended for conventional cellular users to increase the network capacity and spectrum efficiency. The use of Device-to-Device communication leads to certain challenges such as interference of Device-to-Device users with the conventional users. The resource management, network mode selection and power allocation technique in a cellular network with Device-to-Device can improve performance of the system in terms of throughput. To this end, this thesis proposes a technique maximizing the total throughput of cellular users in wireless networks under given quality-of-service and interference constraints. These conditions lead to the complexity that increases with the number of users and Device-to-Device pairs. The proposed methods of spectrum allocation give the close-to-optional solution with reasonable time computation complexity

Radio Resource Management for Cellular Networks Enhanced by Inter-User Communication

The importance of radio resource management will be more and more emphasized in future wireless communication systems. For fair penetration of wireless services and for improved local services, inter-user communication has been receiving wide attention as it opens up various possibilities for user cooperation. The capability of inter-user communication imposes higher demands on radio resource management as additional considerations are needed. The demands for intelligent management of radio resources is also emphasized by the sparsity of radio resources. As the available spectral resources are assessed as under-utilized, much effort is devoted to developing advanced resource management methods for improving the spectral usage efficiency. The research of this thesis has contributed to the radio resource management for cellular networks enhanced by inter-user communication. Recognizing that inter-user communication can be used for message relaying or for direct communication purposes, two use cases are considered that leverage the synergy of users: cooperative relay selection and Device-to-Device (D2D) communication. We identify the importance of stochastic geometry consideration on cellular users for evaluating system performance in cooperative networking. We develop an algorithm for efficiently selecting cooperative users to maximize an End-to-End (e2e) performance metric. We analyze the optimal resource sharing problem between D2D communication and infrastructure-supported communication. We study the impact of imperfect Channel State Information (CSI) on the performance of systems with inter-user communication. Simulation results show that the performance of users with unfavorable propagation conditions can be improved with cooperative communication in a multi-cell cellular environment, at the expense of radio resources. Further, our results show that the selection of multiple cooperative users is beneficial in cases where the candidate cooperative users are spatially distributed. For resource sharing between the D2D and infrastructure-supported communication, our results show that the proposed resource sharing scheme enables higher intra-cell resource reuse without blocking the infrastructure-supported communication

Designing Intelligent Energy Efficient Scheduling Algorithm To Support Massive IoT Communication In LoRa Networks

We are about to enter a new world with sixth sense ability – “Network as a sensor -6G”. The driving force behind digital sensing abilities is IoT. Due to their capacity to work in high frequency, 6G devices have voracious energy demand. Hence there is a growing need to work on green solutions to support the underlying 6G network by making it more energy efficient. Low cost, low energy, and long-range communication capability make LoRa the most adopted and promising network for IoT devices. Since LoRaWAN uses ALOHA for multi-access of channels, collision management is an important task. Moreover, in massive IoT, due to the increased number of devices and their Adhoc transmissions, collision becomes and concern. Furthermore, in long-range communication, such as in forests, agriculture, and remote locations, the IoT devices need to be powered using a battery and cannot be attached to an energy grid. LoRaWAN originally has a star network wherein IoT devices communicated to a single gateway. Massive IoT causes increased traffic at a single gateway. To address Massive IoT issues of collision and gateway load handling, we have designed a reinforcement learning-based scheduling algorithm, a Deep Deterministic policy gradient algorithm with channel activity detection (CAD) to optimize the energy efficiency of LoRaWAN in cross-layer architecture in massive IoT with star topology. We also design a CAD-based simulator for evaluating any algorithms with channel sensing. We compare energy efficiency, packet delivery ratio, latency, and signal strength with existing state of art algorithms and prove that our proposed solution is efficient for massive IoT LoRaWAN with star topology

Kaistan ulkopuolisten todennuskanavien arviointi

One of the challenges in entirely wireless communication systems is authentication. In pervasive computing and peer-to-peer networks, it is often not possible to rely on the existence of a trusted third party or other infrastructure. Therefore, ad hoc verification of keys via an out-of-band (OOB) channel is often the only way to achieve authentication. Nimble out-of-band for EAP (EAP-NOOB) protocol is intended for bootstrapping security between IoT devices with no provisioned authentication credentials and minimal user interface. The protocol supports a user-assisted OOB channel to mutually authenticate the key-exchange performed over an insecure wireless network between the peer and the server. The protocol allows peers to scan for available networks and, based on the results, generate multiple dynamic OOB messages. The user then delivers one of these messages to the server to register the device and authenticate the key-exchange. We implemented the OOB channels using NFC, QR codes and sound with EAP-NOOB as the bootstrapping protocol. The implementation requires an auxiliary device such as the user's smartphone. We evaluated the usability and security as well as the benefits and limitations of the OOB channels. Our results show that NFC and QR codes are capable in displaying multiple OOB messages while the sound-based channel is suitable for one or two messages due to its lower bandwidth. When the peer device generates multiple OOB messages, the process becomes more complex for the user who needs to browse through them and identify the correct server. However, we showed that this cumbersome step can be removed with the help of a mobile application. Furthermore, we identified vulnerabilities in each technology when used as an OOB channel. While some of these vulnerabilities can be mitigated with the mobile application, some require more refined solutions.Yksi täysin langattomien järjestelmien haasteista on todennus. Sulautetussa tietotekniikassa sekä vertaisverkkoissa ei usein voida luottaa maailmanlaajuisesti luotettavan kolmannen osapuolen olemassaoloon. Siksi salausavainten ad hoc-varmennus erillistä tiedonsiirtokanavaa (OOB) käyttäen on usein ainoa ratkaisu turvallisen kommunikaation käynnistämiseksi. Se luo resilienssiä eri hyökkäyksiä vastaan tuomalla järjestelmään toisen, itsenäisen tiedonsiirtokanavan. EAP-NOOB protokolla on tarkoitettu IoT-laitteille, joilla on minimaalinen käyttöliittymä eikä esiasennettuja avaimia. EAP-NOOB tukee käyttäjäavustettua OOB-tiedonsiirtokanavaa, jota käytetään todentamaan suojaamattomassa verkossa suoritettu laitteen ja palvelimen keskinäinen salausavainten vaihto. Protokolla sallii laitteiden kartoittaa käytettävissä olevia verkkoja ja tuottaa sen perusteella dynaamisia todennusviestejä, jotka käyttäjä toimittaa palvelimelle laitteen rekisteröimiseksi. Tässä työssä tutkittiin EAP-NOOB protokollan OOB kanavaa käyttäen NFC:tä, QR-koodeja ja ääntä. Todennusviestin lukeminen laitteelta vaatii käyttäjältä älypuhelimen. Työssä arvioitiin toteutettujen todennuskanavien käytettävyyttä, tietoturvaa, hyötyjä sekä näitä rajoittavia tekijöitä. Työn tulokset osoittavat, että NFC ja QR-koodit soveltuvat näyttämään useita OOB-viestejä. Sen sijaan äänipohjainen kanava soveltuu vain yhdelle tai kahdelle viestille hitaamman tiedonsiirron johdosta. Kun IoT-laite tuottaa useita OOB-viestejä, käyttäjäkokemus muuttuu monimutkaisemmaksi, koska käyttäjän on tunnistettava oikea viesti ja palvelin. Työssä osoitetaan, että tämä käyttäjälle hankala vaihe voidaan välttää erillisellä mobiilisovelluksella. Lisäksi työssä tunnistettiin toteutettujen tiedonsiirtomenetelmien haavoittuvuuksia, kun niitä käytettiin OOB-kanavana. Vaikka osa näistä haavoittuvuuksista voidaan eliminoida mobiilisovelluksen avulla, jotkut niistä vaativat tehokkaampia ratkaisuja