Mobile communication advanced technology strategy: OFDM or CDMA?
A new conception of perspective technology of mobile communications as a result of analysis of architecture and characteristics communication links of OFDM- and CDMA-systems. In down link use orthogonal division and QAM of spread spectrum signals are based on Vilencin-Crestenson functions with M-sequences. In up-links – pseudo-ortogonal code of sequences information bits with used spread spectrum signals. Analyses the dignities and lacks of new conception of perspective down- and up-lincks architecture. Key words: OFDM, CDMA, Vilencin-Crestenson functions, spectrum signals.
SEMYNOZHENKO V.P., GORITSKI V.M.,VOROBIYENKO P.P., TIKHONOV V.I.
ITT technology network integration concept
The paper focuses the issues of next generation network architecture and technologies design. A new three layer open system interconnection reference model is developed. The basic principles of multipurpose network meta-protocol and dynamic flow switching are studied.
Key words: open system interconnection model, network meta-protocol, dynamic flow stitching, real time traffic.
Simulation results of a NGN network’s operation under significant traffic growth. Part 1
In the article, the results of the simulation model designed for studies of quality of service in next generation network under dramatic increase of traffic are considered. Single-line teletraffic system is used as a model. The input to the system is the flow of calls (IP-packets) with different distribution laws. Call service time is constant. Queue is limited. Obtained results allow study of real processes of IP-packets service in the next generation network.
Key words: traffic, simulation model, teletraffic system, IP-packet delay, mean of distribution, coefficient of variation.
Analysing statistical parameters of subscriber lines in railway communication networks
The following structural parameters analysis are shown in this article: the length of subscriber lines on the trunk and distribution sections of the subscriber access network, capacity of subscriber cables. These parameters are analyzed for the three railway stations types different in rang.
Key words: cable length, subscriber cable capacity, access network, trunk section.
KLEYKO D.V., LYAMIN N.V.
Modified algorithm of IEEE 802.22 standard dynamic frequency hopping (DFH)
In this paper we introduce conception of using of the vacant frequency resource appearing when using standard DFH scheme. Besides, adaptation of the model of including new DFHC members for parallel addition into DFH scheme of several WRAN’s is proposed.
Key words: IEEE 802.22 standard, dynamic frequency hopping (DFH), change channels scheme.
Power calculation in transmitting path load
The technique of calculation of power in the load of a transmission path, containing both the segments of high-frequency feeder lines and four-poles with the help of the mathematical apparatus of the theory of long lines is proposed.
Key words: transmission path, power in the load, feeder, four-pole.
YELKIN S.N., KILDISHEVA O.E., LOBOV S.A., CHEMIRENKO V.P.
Methods of defining prospective ways for communication engineering development