Cross-layer performance control of wireless channels using active local profiles

To optimize performance of applications running over wireless channels state-of-the-art wireless access technologies incorporate a number of channel adaptation mechanisms. While these mechanisms are expected to operate jointly providing the best possible performance for current wireless channel and traffic conditions, their joint effect is often difficult to predict. To control functionality of various channel adaptation mechanisms a new cross-layer performance optimization system is sought. This system should be responsible for exchange of control information between different layers and further optimization of wireless channel performance. In this paper design of the cross-layer performance control system for wireless access technologies with dynamic adaptation of protocol parameters at different layers of the protocol stack is proposed. Functionalities of components of the system are isolated and described in detail. To determine the range of protocol parameters providing the best possible performance for a wide range of channel and arrival statistics the proposed system is analytically analyzed. Particularly, probability distribution functions of the number of lost frames and delay of a frame as functions of first- and second-order wireless channel and arrival statistics, automatic repeat request, forward error correction functionality, protocol data unit size at different layers are derived. Numerical examples illustrating performance of the whole system and its elements are provided. Obtained results demonstrate that the proposed system provide significant performance gains compared to static configuration of protocols

An Accurate Approximation of Resource Request Distributions in Millimeter Wave 3GPP New Radio Systems

The recently standardized millimeter wave-based 3GPP New Radio technology is expected to become an enabler for both enhanced Mobile Broadband (eMBB) and ultra-reliable low latency communication (URLLC) services specified to future 5G systems. One of the first steps in mathematical modeling of such systems is the characterization of the session resource request probability mass function (pmf) as a function of the channel conditions, cell size, application demands, user location and system parameters including modulation and coding schemes employed at the air interface. Unfortunately, this pmf cannot be expressed via elementary functions. In this paper, we develop an accurate approximation of the sought pmf. First, we show that Normal distribution provides a fairly accurate approximation to the cumulative distribution function (CDF) of the signal-to-noise ratio for communication systems operating in the millimeter frequency band, further allowing evaluating the resource request pmf via error function. We also investigate the impact of shadow fading on the resource request pmf.Comment: The 19th International Conference on Next Generation Wired/Wireless Networks and Systems (New2An 2019

Modeling local stationary behavior of Internet traffic

Non-stationary behavior of aggregated IP traffic patterns was demonstrated in a number of studies. However, noneof those did either consider practical aspects of this phenomenon or propose suitable model to capture it. Searching for model for IP traffic aggregates we introduce the concept of local stationarity and demonstrate that it allows to model traffic patterns measured in high-speed operational networks. The proposed model is on-line in nature and suitable for real-time estimation of the traffic state in terms of piecewise covariance stationary stochasticprocess. As a basic tool of the model we use change-pointstatistical test allowing us to dynamically and automaticallydetermine whether statistical characteristics of the traffic pattern changes and, if so, estimate new parameters of the traffic pattern. We provide numerical examples and discuss applications of the proposed model that include but not limited to dynamic resource reservation, routing with guaranteed bandwidth, etc

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

Automatic Bandwidth Adjustment for Content Distribution in MPLS Networks

Aggregates of real-time traffic may experience changes in their statistical characteristics often manifesting non stationary behavior. In multi protocol label switching (MPLS) networks this type of the traffic is assigned constant amount of resources. This may result in ineffective usage of resources when the load is below than expected or inappropriate performance when the load is higher. In this paper we propose new algorithm for dynamic resource adaptation to temporarily changing traffic conditions. Assuming that network nodes may reallocate resources on-demand using automatic bandwidth adjustment capability of MPLS framework, the proposed algorithm, implemented at ingress MPLS nodes, dynamically decides which amount of resources is currently sufficient to handle arriving traffic with given performance metrics. This decision is then communicated to interior MPLS nodes along the label switched path. As a basic tool of the algorithm we use change-point statistical test that signals time instants at which statistical characteristics of traffic aggregates change. The major advantage of the proposed approach is that it is fully autonomous, that is, network nodes do not need any support from hosts in terms of resource reservation requests. The proposed algorithm is well suited for traffic patterns experiencing high variability, especially, for non stationary type of the traffic

Characterizing the Degree of LTE Involvement in Supporting Session Continuity in Street Deployment of NR Systems

The prospective roll out of recently standardized New Radio (NR) systems operating in millimeter wave frequency band pose unique challenges to network engineers. In this context, the support of NR-based vehicle-to-infrastructure communications is of special interest due to potentially high speeds of user equipment and semi-stochastic dynamic blockage conditions of propagation paths between UE and BR base station (BS). In this conditions even the use of advanced NR functionalities such as multiconnectivity supporting active connections to multiple BSs located nearby may not fully eliminate outages. Thus, to preserve session continuity for UEs located on vehicles a degree of LTE support might be required. In this paper, we quantify the amount of LTE support required to maintain session continuity in street deployment of NR systems supporting multiconnectivity capabilities. Particularly, we demonstrate that it is heavily affected by the traffic conditions, inter-site distance between NR BSs and the degree of multiconnectivity.acceptedVersionPeer reviewe

An Accurate Approximation of Resource Request Distributions in Millimeter Wave 3GPP New Radio Systems

The recently standardized millimeter wave-based 3GPP New Radio technology is expected to become an enabler for both enhanced Mobile Broadband (eMBB) and ultra-reliable low latency communication (URLLC) services specified to future 5G systems. One of the first steps in mathematical modeling of such systems is the characterization of the session resource request probability mass function (pmf) as a function of the channel conditions, cell size, application demands, user location and system parameters including modulation and coding schemes employed at the air interface. Unfortunately, this pmf cannot be expressed via elementary functions. In this paper, we develop an accurate approximation of the sought pmf. First, we show that Normal distribution provides a fairly accurate approximation to the cumulative distribution function (CDF) of the signal-to-noise ratio for communication systems operating in the millimeter frequency band, further allowing evaluating the resource request pmf via error function. We also investigate the impact of shadow fading on the resource request pmf.acceptedVersionPeer reviewe