Digital cellular-its roots and its future

Uddenfeldt, J.

doi:10.1109/5.681366

Cited by 9 publications

(6 citation statements)

References 7 publications

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“…In other words, the condition of the MP algorithm is verified when in each group of three cells, with a common vertex, the active channels are less than C 1 for microcells and less than C 2 for macrocells. It is to be noted, however, that as discussed in [21], [25], in some cases the state space determined by (1) is larger than the state space determined by MP, but the difference in terms of performance can be disregarded. This MP algorithm, although not always completely feasible, is attractive because, apart from being an analytically tractable strategy, it is in some sense optimal.…”

Section: B Resources Allocation Algorithmmentioning

confidence: 99%

“…The microcell transition rate μ r , measured in transitions per hour [tr/h], represents user mobility and is related to the diameter d 1 of a microcell and with the average speed, v r , of users 1 d v r r ∝ μ with r = 1, 2.…”

Section: Multi-class Mobility Modelingmentioning

confidence: 99%

“…Moreover, in the evaluation of load factor, we have to take into account [22] the blocking probability of a new call in microcell z, P B1 (z), due to the constraints imposed by expression (1). In fact, in the generic microcell z, a call request might be rejected and passed to the umbrella-macrocell if (1) is not satisfied, even if the number of active calls in the microcell z is zero.…”

Section: B Microcell Model Characterizationmentioning

confidence: 99%

“…An important performance parameter is the blocking probability of a new call for each mobility class. In general the event {new call blocked} occurs when a user attempts a new call but there are no available channels, according to (1).…”

Section: A Blocking Probability Of a New Callmentioning

confidence: 99%

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Teletraffic analysis of hierarchical cellular communication networks

Boggia

Camarda

Fonzo

2003

IEEE Trans. Veh. Technol.

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The sustained increase of users and the request for advanced multimedia services are some of the key motivations for designing new high capacity cellular telecommunication systems. The proposals which are being pursued by several studies and field implementations consider hierarchical architectures and dynamic resource allocation. In this paper a hierarchical cellular communication network is analyzed, taking into account user mobility and exploiting dynamic channel allocation schemes. In particular, a finite number of users has been considered, moving at different speeds in a geographical region covered by a finite number of cells structured in two hierarchical levels: microcells and macrocells. For such a system, a mobility model and a traffic model have been developed, both based on queueing networks, analyzing Maximum Packing (MP), a dynamic channel allocation scheme. The obtained results, validated by simulation experiments, allow the evaluation of main system performance parameters in terms of new call blocking probability, handoff blocking probability and forced termination probability as a function of load and system parameters. Index Terms-Cellular Networks, Queueing Model, User Mobility, Hierarchical Network. I. INTRODUCTIONELLULAR telephony is one of the consumer electronics fields that has experienced an explosive development in recent years. In fact, the sustained increase of users together with the request for advanced multimedia services are driving the research for the development of second generation systems (for instance, see the GSM phase 2+ [1]) and the definition of new standards for third generation systems (e.g., UMTS [2]). The transmission frequencies of evolved second generation and third generation systems are about 2 GHz, with a microcell coverage, while the second generation systems (for example, the first version of GSM) use frequencies of about 900 MHz with a macrocell coverage.It should be pointed out that a coverage based only on microcells is not always desirable. In fact, in this kind of cell, the propagation conditions are highly dependent on the environment: width of the streets, moving obstacles and so on. Therefore, when, as an example, users turn a street corner, they may experience a dramatic decrease in signal power. Such rapid variations of the received power level may cause communication interruptions for high-speed users if the network does not have enough time for the handoff process (assuming that there are available resources for this operation). Moreover, such high-speed users may generate lots of handoffs causing a significant increase in signaling traffic in the network. In fact, each handoff process involves various control functions both on wired and wireless networks. Such control procedures, necessary to set up a connection with the new base station and to update state information, introduce delay in the transmission, which can cause catastrophic consequences for multimedia real time traffic. Therefore, it is necessary to preserve the macrocell coverage that m...

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Section: B Resources Allocation Algorithmmentioning

confidence: 99%

Section: Multi-class Mobility Modelingmentioning

confidence: 99%

Section: B Microcell Model Characterizationmentioning

confidence: 99%

Section: A Blocking Probability Of a New Callmentioning

confidence: 99%

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Teletraffic analysis of hierarchical cellular communication networks

Boggia

Camarda

Fonzo

2003

IEEE Trans. Veh. Technol.

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“…Os sistemas 2G são baseados na tecnologia digital de transmissão tanto de voz quanto de dados e nas tecnologias de acesso TDMA e CDMA. Outra tecnologia importante incorporada pelos sistemas 2G é o Frequency Hopping (FH) que, juntamente com a codificação de canal, permite reduzir o impacto do desvanecimento no móvel [38]. Além disso, o FH também permite diminuir o nível de interferência proveniente de outras células, aumentando o reuso de frequências e, portanto, a capacidade.…”

Section: Pequena História Do Sistema Celularunclassified

Algoritmos de processamento espacial para enlaces de comunicação sem fio

Filho¹,

Romano²

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Esse trabalho considera o uso de processamento espacial aplicado aos enlaces de comunicação sem fio, com o objetivo da redução da interferência co-canal. No enlace reverso, foram abordadas as soluções baseadas em filtragem com restrição (LCMV) e suas versões adaptativas. Introduzimos as restrições autovetoriais, de forma a lidar com o espalhamento angular e propusemos uma nova formulação que evita a estimação das direções de chegada dos sinais, considerada um dos principais obstáculos para utilização prática das técnicas LCMV. No enlace direto, tratamos o problema da minimização da potência de transmissão de forma conjunta, tanto em relação aos filtros espaciais quanto às potências de transmissão. Propusemos então um algoritmo exato para obter a solução ótima dessa minimização, do qual derivamos uma versão rápida, sendo sua principal vantagem o ganho de complexidade computacional quando a matriz de autocorrelação espacial é atualizada continuamente.

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Voice access of global information for broad-band wireless: technologies of today and challenges of tomorrow

Lee

2001

Proc. IEEE

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The rapid development of the Internet and the World Wide Web has created a global network that will soon become a physical embodiment of the entire human knowledge and a complete integration of the global information activities. The traditional approach to access the network is through a computer physically tied to the network. As broad-band wireless takes off, the traditional tethered approach will gradually become obsolete. It is believed that one of the most natural and user-friendly approaches for accessing the network will be via human voice, and the integration of spoke language processing technologies with broad-band wireless technologies will be a key to the evolution of a broad-band wireless information community. This paper offers a vision of the above concept. Technical considerations and some typical example applications of accessing the information and services using voice in a broad-band wireless environment are discussed. Fundamentals of spoken language processing technologies that are crucial in such a broad-band wireless environment are briefly reviewed. Technical challenges caused by the unique nature of wireless mobile communications are also presented along with some possible solutions.

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Digital cellular-its roots and its future

Cited by 9 publications

References 7 publications

Teletraffic analysis of hierarchical cellular communication networks

Teletraffic analysis of hierarchical cellular communication networks

Algoritmos de processamento espacial para enlaces de comunicação sem fio

Voice access of global information for broad-band wireless: technologies of today and challenges of tomorrow

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