Poznan University of Technology
Electronics and Telecommunications
This paper is to contribute a new dynamic channel access method for wireless local area networks. It allows a station accessing the 80 or 160MHz channel to capture every idle non-primary 20MHz channel along with the primary 20MHz channel,... more
This paper is to contribute a new dynamic channel access method for wireless local area networks. It allows a station accessing the 80 or 160MHz channel to capture
every idle non-primary 20MHz channel along with the primary 20MHz channel, whereas the number of channel configurations in which the station can transmit according to the 802.11ac standard is strictly limited. Simulation results shown in the paper prove the proposed access method to be superior to the method provided by the 802.11ac standard in terms of average network throughput. What is important for legacy reasons, the proposed method employs the conventional clear channel assessment function to determine which of the 20MHz channels are idle and which are busy. The paper proposes a new receiver design that is able to reject the adjacent channel interference, arising as a result of the presence of the legacy 802.11a/n station signals inside the 80 or 160MHz accessed channel.
every idle non-primary 20MHz channel along with the primary 20MHz channel, whereas the number of channel configurations in which the station can transmit according to the 802.11ac standard is strictly limited. Simulation results shown in the paper prove the proposed access method to be superior to the method provided by the 802.11ac standard in terms of average network throughput. What is important for legacy reasons, the proposed method employs the conventional clear channel assessment function to determine which of the 20MHz channels are idle and which are busy. The paper proposes a new receiver design that is able to reject the adjacent channel interference, arising as a result of the presence of the legacy 802.11a/n station signals inside the 80 or 160MHz accessed channel.
- by Maciej Krasicki and +1
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- Channel Access Scheduling
This correspondence considers the minimum Euclidean distance properties, upper bounds on the minimum distance, power density spectrum, and power-bandwidth tradeoff for Mary phase codes where K different symbol lengths are used in a... more
This correspondence considers the minimum Euclidean distance properties, upper bounds on the minimum distance, power density spectrum, and power-bandwidth tradeoff for Mary phase codes where K different symbol lengths are used in a cyclical manner. When these lengths are all related to each other as rational numbers, they give a finite-state Markov (trellis) description of the signal. In this paper, K = 2 is assumed. It is found that from the point of view of minimum distance and spectral properties multi-T phase codes are very similar to multi-h codes. It is also shown that quaternary codes give considerable improvement over binary codes. * Pawel Szulakiewicz, biography and photograph not available for publication.
This paper focuses on the applicability of Bit-Interleaved Space-Time Coded Modulation with Iterative Decoding (BI-STCM-ID) to Wireless Local Area Networks (WLAN). A new intuitive space-time diversity scheme, which ensures a low error... more
This paper focuses on the applicability of Bit-Interleaved Space-Time Coded Modulation with Iterative Decoding (BI-STCM-ID) to Wireless Local Area Networks (WLAN). A new intuitive space-time diversity scheme, which ensures a low error rate for small signal-to-noise ratios (SNR) and good asymptotic performance, is provided. The presented technique can ensure compatibility with today's WLAN specifications. The EXtrinsic Information Transfer Chart (EXIT) and the bit error rate (BER) simulations confirm its usefulness.
5G systems are expected to utilize frequency bands above 6 GHz in the so-called millimeter-wave (mmWave) spectrum because of large bandwidths. It is well know that higher carrier frequency bands suffer from higher path loss attenuation.... more
5G systems are expected to utilize frequency bands above 6 GHz in the so-called millimeter-wave (mmWave) spectrum because of large bandwidths. It is well know that higher carrier frequency bands suffer from higher path loss attenuation. It addition, dynamic blockages can be a challenge for achieving good coverage. Therefore, millimeter-wave deployments require cell densification to achieve high data rates. However, densification further leads to challenges in the system design because of the need for low cost backhaul. The concept of wireless self-backhauling (sBH) aims to provide a provide a backhaul solution at reduced cost. Self-backhaul solution makes use of integrated access and backhaul (IAB) at each base station to realize on-demand flexible backhaul and access. In this paper, we investigate the performance of in-band self-backhauling with integrated access and backhaul in a real-life street canyon scenario. We consider centralized scheduling which can effectively allocate radio resources for backhaul and access on a time slot basis with half duplex constraint. The centralized scheduler further mitigates cross-interference between backhaul and access using a beam coordination and interference cancellation. Our results show that the proposed relaying concept offers good user throughput gains for cell edge users and is also robust to offloading of users to relay cells. Results also show that interference cancellation receivers can improve the uplink and backhaul spectral efficiency in IAB deployment by around 10%.
This paper reports intermediate transceiver and frame structure concepts and corresponding results from the European FP7 research project 5GNOW. The core is the unified frame structure concept which supports an integrated 5G air... more
This paper reports intermediate transceiver and frame structure concepts and corresponding results from the European FP7 research project 5GNOW. The core is the unified frame structure concept which supports an integrated 5G air interface, capable of dealing both with broadband data services and small packet services within the same band. It is essential for this concept to introduce waveforms which are more robust than OFDM, e.g., with respect to time-frequency misalignment. Encouraging candidate waveform technologies are presented and discussed with respective results. This goes along with the corresponding multiple access technologies using multi-layered signals and advanced multi-user receivers. In addition we introduce new (compressive) random access strategies to enable "one shot transmission" with greatly reduced control signaling particularly for sporadic traffic by orders of magnitude. Finally, we comment on the recent results on the 5GNOW networking interface. The intermediate results of 5GNOW lay the ground for the standardization path towards a new 5G air interface beyond LTE-A.
- by Mateusz Buczkowski and +1
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In this paper, a new approximate method of point-to-group blocking probability calculation in switching networks carrying a mixture of different multi-rate unicast and multicast traffic streams is presented. Special attention is paid to... more
In this paper, a new approximate method of point-to-group blocking probability calculation in switching networks carrying a mixture of different multi-rate unicast and multicast traffic streams is presented. Special attention is paid to the methods for determining the effective availability parameter in the case of multicast connections. The results of analytical calculations are compared with the data of digital simulations of switching networks with unicast and multicast connections.
In this paper reservation algorithms for multi-service switching networks are proposed. Two new approximate methods of the point-to-point blocking probability calculation in the multi-service switching networks are also presented in the... more
In this paper reservation algorithms for multi-service switching networks are proposed. Two new approximate methods of the point-to-point blocking probability calculation in the multi-service switching networks are also presented in the paper. These methods can be used for blocking calculation in the switching networks with and without reservation. Special attention is paid to the method for determining the effective availability, which directly affects the accuracy of the final results. The results of analytical calculations are compared with the data of digital simulation of switching networks without and with reservation.
Three reservation algorithms for the limited-availability system are proposed and compared in the paper. These algorithms can be used for call blocking equalisation in outgoing links of multiservice switching networks. Two approximate... more
Three reservation algorithms for the limited-availability system are proposed and compared in the paper. These algorithms can be used for call blocking equalisation in outgoing links of multiservice switching networks. Two approximate methods of equalised blocking probability calculation in the system with limited availability are proposed. Results of analytical calculations are compared with results of digital simulation of limited availability groups and switching networks with reservation. These researches have confirmed a great accuracy of the proposed calculation methods. The formulae derived by the authors can be useful for the analysis and design ofiSDN and B-ISDN systems.
The paper presents and describes the uplink blocking probability calculation method in cellular systems with WCDMA radio interface and finite source population. The method is based on the model of the full availability group with... more
The paper presents and describes the uplink blocking probability calculation method in cellular systems with WCDMA radio interface and finite source population. The method is based on the model of the full availability group with multi-rate traffic streams. The proposed method can be easily applied to 3G network capacity calculations during planning stages of its design.
This book will be an invaluable guide for professional engineers (radio planning engineers, optimization engineers, transmission engineers, core network engineers, Service Management engineers) working in the areas of mobile wireless... more
This book will be an invaluable guide for professional engineers (radio planning engineers, optimization engineers, transmission engineers, core network engineers, Service Management engineers) working in the areas of mobile wireless networks technology, not only in optimization process, but also in profitability assessment of newly implemented services (i.e. in NPV - Net Present Value analysis), and researchers and scientists. Advanced students in the fields of mobile communications networks and systems will also find this book insightful.
The Ant Colony Optimization (ACO) metaheuristic is a versatile algorithmic optimization approach based on the observation of the behaviour of ants. As a result of numerous analyses, ACO has been applied to solving various combinatorial... more
The Ant Colony Optimization (ACO) metaheuristic is a versatile algorithmic optimization approach based on the observation of the behaviour of ants. As a result of numerous analyses, ACO has been applied to solving various combinatorial problems. The ant colony metaheuristic proves itself to be efficient in solving NP-hard problems, often generating the best solution in the shortest amount of time. However, not enough attention has been paid to ACO as a means of solving problems that have optimal solutions which can be found using other methods.
The shortest path problem is undoubtedly one of the aspects of great significance to navigation and telecommunications. It is used, amongst others, for determining the shortest route between two geographical locations, for routing in packet networks, and to balance and optimize network utilization. Thus, this article introduces ShortestPathACO, an Ant Colony Optimization based algorithm designed to find the shortest path in a graph. The algorithm consists of several subproblems that are presented successively. Each subproblem is discussed from many points of view to enable researchers to find the most suitable solutions to the problems they investigate.
The shortest path problem is undoubtedly one of the aspects of great significance to navigation and telecommunications. It is used, amongst others, for determining the shortest route between two geographical locations, for routing in packet networks, and to balance and optimize network utilization. Thus, this article introduces ShortestPathACO, an Ant Colony Optimization based algorithm designed to find the shortest path in a graph. The algorithm consists of several subproblems that are presented successively. Each subproblem is discussed from many points of view to enable researchers to find the most suitable solutions to the problems they investigate.
The development of concepts derived from the generic approach to solving the problem of the shortest path resulted in numerous and various algorithms that appeared over the past decades. The studies on the most basic operation aimed at... more
The development of concepts derived from the generic approach to solving the problem of the shortest path resulted in numerous and various algorithms that appeared over the past decades. The studies on the most basic operation aimed at the determination of the shortest path between two given points in a graph (in other words, often a network) have resulted in sophisticated solutions designed for more and more demanding applications. Those include finding the sets of paths with the shortest distance between all pairs of nodes or searching for a shortest path tree. The aim of the present article is to give the reader an introduction to the problem of the shortest path and a detailed review of two groups of selected algorithms designed to solve particular problems. In the study described herein, different algorithms have been examined for their efficacy in their operation in directed graphs of different type represented in a well-defined data structure. The empirical simulation-based analysis proves that the performance varies among algorithms under investigation and allows to suggest, which methods ought to be used to solve specific variants of the shortest path problem and which algorithms should be avoided or used with caution.
This paper presents an approximate calculation methodology of the occupancy distribution and the blocking probability in a virtual circuit switching node with multi-rate unicast and multicast traffic streams. Particular traffic streams... more
This paper presents an approximate calculation methodology of the occupancy distribution and the blocking probability in a virtual circuit switching node with multi-rate unicast and multicast traffic streams. Particular traffic streams are generated by an infinite as well as by a finite population of traffic sources. The model enables calculations of any structure of the groups forming the outgoing directions of the node. Additionally, bandwidth reservation algorithms are also proposed in order to improve traffic characteristics of different traffic classes. The results of the analytical calculations have been compared with the simulation results of a switching node carrying multicast and unicast traffic streams.
The paper proposes a new approximate calculation method of occupancy distribution and blocking probability in the full-availability group (FAG) with multi-rate traffic streams and bandwidth reservation. The algorithm involves calculation... more
The paper proposes a new approximate calculation method of occupancy distribution and blocking probability in the full-availability group (FAG) with multi-rate traffic streams and bandwidth reservation. The algorithm involves calculation of system state probabilities by a convolution operation. In the paper, an effective method of calculating state probabilities in a reservation space of the system is derived. The analytical results of blocking probabilities in the FAG with bandwidth reservation, obtained on the basis of the proposed analytical method, are compared with the data obtained on the basis of other known analytical methods and with the simulation results. The accuracy of the proposed method is evaluated for different multi-rate Bernoulli (Erlang), Poisson (Engset), Pascal traffic streams. The method proposed is characterised by lower complexity than the convolution algorithm for the FAG with bandwidth reservation devised earlier.
- by Maciej Stasiak and +1
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- Algorithm, Probability, Stochastic processes, Simulation
In this paper, a new approximate method of pointto-group blocking probability calculation in switching networks carrying a mixture of different multi-rate unicast and multicast traffic streams is presented. Special attention is paid to... more
In this paper, a new approximate method of pointto-group blocking probability calculation in switching networks carrying a mixture of different multi-rate unicast and multicast traffic streams is presented. Special attention is paid to the methods for determining the effective availability parameter in the case of multicast connections. The results of analytical calculations are compared with the data of digital simulations of switching networks with unicast and multicast connections.
This paper presents a complete methodology for modeling gradings also called non-full-availability groups servicing single-service and multi-service traffic streams. The methodology worked out by the authors makes it possible to determine... more
This paper presents a complete methodology for modeling gradings also called non-full-availability groups servicing single-service and multi-service traffic streams. The methodology worked out by the authors makes it possible to determine traffic characteristics of various types of gradings with state-dependent call arrival processes, including a new proposed structure of the Erlang's Ideal Grading with the multirate links. The elaborated models of the gradings can be used for modeling different systems of modern networks, for example, the radio interfaces of the UMTS system, switching networks carrying a mixture of different multirate traffic streams, and videoon-demand systems. The results of the analytical calculations are compared with the results of the simulation data for selected gradings, which confirm high accuracy of the proposed methodology.
- by Maciej Stasiak and +1
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- Engineering, Mathematical Sciences
In the paper a new approximate calculation method of the occupancy distribution and the blocking probability in the full-availability group (FAG) with multi-rate traffic streams and bandwidth reservation is proposed. The algorithm... more
In the paper a new approximate calculation method of the occupancy distribution and the blocking probability in the full-availability group (FAG) with multi-rate traffic streams and bandwidth reservation is proposed. The algorithm consists in calculation of system state probabilities by the convolution operation. In the paper, an effective method of calculating state probabilities in a reservation space of the system is derived. Analytical results of the blocking probabilities in the FAG with bandwidth reservation, obtained on the basis of the proposed method, are compared with simulation results.
- by Maciej Stasiak and +1
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