Оценка требуемых скоростей передачи данных при организации беспроводной связи между ядрами центрального процессора

In this paper, a principal architecture of common purpose CPU and its main components are discussed, CPUs evolution is considered and drawbacks that prevent future CPU development are mentioned. Further, solutions proposed so far are addressed and a new CPU architecture is introduced. The proposed architecture is based on wireless cache access that enables a reliable interaction between cores in multicore CPUs using terahertz band, 0.1-10THz. The presented architecture addresses the scalability problem of existing processors and may potentially allow to scale them to tens of cores. As in-depth analysis of the applicability of the suggested architecture requires accurate prediction of traffic in current and next generations of processors, we consider a set of approaches for traffic estimation in modern CPUs discussing their benefits and drawbacks. The authors identify traffic measurements by using existing software tools as the most promising approach for traffic estimation, and they use Intel Performance Counter Monitor for this purpose. Three types of CPU loads are considered including two artificial tests and background system load. For each load type the amount of data transmitted through the L2-L3 interface is reported for various input parameters including the number of active cores and their dependences on the number of cores and operational frequency.Рассматривается современная архитектура процессоров общего назначения, ее основные компоненты, описывается эволюция, а также подчеркиваются проблемы, препятствующие дальнейшему развитию такой архитектуры. Далее рассмотрены предложенные ранее пути развития процессоров, подчеркиваются их недостатки и предлагается новая архитектура, основанная на беспроводном доступе к кеш-памяти в многоядерных процессорах. В основе предлагаемого решения лежит организация надежного обмена данными между кешем третьего уровня и ядрами процессора через беспроводной канал в терагерцовом диапазоне. Таким образом, масштабируемость системы повышается до десятков и, потенциально, сотен ядер. В то же время, детальный анализ применимости предложенного решения требует точного предсказания количества информации, передаваемой между ядрами и кеш-памятью в процессорах текущего и следующего поколения. В данной работе рассматриваются основные подходы к построению оценки количества передаваемых данных, выделены их достоинства и недостатки. Авторы останавливают свой выбор на непосредственных измерениях количества данных с помощью существующих программных инструментов. Для измерений используется программный инструмент Intel Performance Counter Monitor, позволяющей оценить количе- ство данных, передаваемых между кеш-памятью второго и третьего уровней каждого ядра. В работе рассматриваются три варианта нагрузки на ядро – два искусственных теста и фоновая нагрузка от операционной системы. Для каждого типа нагрузки в работе приведены численные значения количества данных, проходящих по шине между кешем второго и третьего уровней, и показана их зависимость от тактовой частоты работы процессора и количества ядер

Evaluating multi-connectivity in 5G NR systems with mixture of unicast and multicast traffic

The future 5G New Radio (NR) systems are expected to support both multicast and unicast traffic. However, these traffic types require principally different NR system parameters. Particularly, the area covered by a single antenna configuration needs to be maximized when serving multicast traffic to efficiently use system resources. This prevents the system from using the maximum allowed number of antenna elements decreasing the inter-site distance between NR base stations. In this paper, we formulate a model of NR system with multi-connectivity capability serving a mixture of unicast and multicast traffic types. We show that multi-connectivity enables a trade-off between new and ongoing session drop probabilities for both unicast and multicast traffic types. Furthermore, supporting just two simultaneously active links allows to exploit most of the gains and the value of adding additional links is negligible. We also show that the service specifics implicitly prioritize multicast sessions over unicast ones. If one needs to achieve a balance between unicast and multicast session drop probabilities, explicit prioritization mechanism is needed at NR base stations.acceptedVersionPeer reviewe

Upper bound on capacity of 5G mmWave cellular with multi-connectivity capabilities

Outage events caused by dynamic blockage of a radio signal propagation path are one of the key challenges in 5G millimetre-wave (mmWave) cellular networks. To mitigate them, Third Generation Partnership Project standardisation has recently ratified multi-connectivity techniques aiming to enable user connectivity to several base stations simultaneously, while switching between them whenever the currently active connection becomes blocked. A closed-form upper bound on the probability density function of the respective system capacity in a random field of moving blockers is obtained.acceptedVersionPeer reviewe

Random Triangle: A Baseline Model for Interference Analysis in Heterogeneous Networks

In emerging heterogeneous networks (HetNets), a wide range of the underlying performance evaluation problems is related to wireless interference characterization and can be reduced to investigating the distribution of a side length in a random triangle. In this paper, we address the task of calculating the side-length distribution in such a triangle determined by the known distributions of its two other sides and the distribution of the angle between them. No restrictions on the distributions of input random variables (RVs) are imposed except for their statistical independence. Our solution delivers a crucial building block for interference analysis in multitier and multiradio HetNets, including mobile device-to-device communication as one of the most extreme interference-limited cases. © 1967-2012 IEEE

Random Triangle: A Baseline Model for Interference Analysis in Heterogeneous Networks

In emerging heterogeneous networks (HetNets), a wide range of the underlying performance evaluation problems is related to wireless interference characterization and can be reduced to investigating the distribution of a side length in a random triangle. In this paper, we address the task of calculating the side-length distribution in such a triangle determined by the known distributions of its two other sides and the distribution of the angle between them. No restrictions on the distributions of input random variables (RVs) are imposed except for their statistical independence. Our solution delivers a crucial building block for interference analysis in multitier and multiradio HetNets, including mobile device-to-device communication as one of the most extreme interference-limited cases. © 1967-2012 IEEE

Session-Level Reliability Analysis for Multi-Service Communication in Autonomous Vehicular Fleets

The support for reliable communication in the increasingly large fleets of autonomous vehicles is one of the important challenges for emerging 5G systems. The presence of heterogeneous data streams of different priority between the connected vehicles (coordinated autonomous driving, platooning, passenger entertainment services, etc.) calls for new methods to estimate the performance characteristics of these systems. In this article, a novel mathematical framework is proposed to model the process of dynamic radio resource (re-)allocation across multiple competing data streams in autonomous vehicular fleets equipped with 5G cellular capabilities. The developed framework is subsequently applied to: (i) study the coexistence of multiple traffic types having different service requirements and (ii) quantify the impact of session prioritization schemes. Our study reveals that the prioritization scheme initially offloading high-rate entertainment sessions, named ESpreempt, in most of the setups achieves a 5-30% performance gain in comparison with the scheme initially offloading low-rate platooning sessions, named PSpreempt. It is also shown that higher variations in the traffic load of autonomous driving sessions have a distinctly negative impact on system-level performance. The outlined framework can be applied in a wide range of 5G vehicular scenarios, as well as extended to capture other categories of data streams in future wireless networks

A Simulation Based Analysis of SINR for Device-to-Device Communications in Circular Clusters

In this contribution we address a common scenario for deviceto-device communications. Using the simulation approach we analyze the interference from a single interferer. The proposed model serves as a basis for general analysis featuring more than a single interferer