Yuri Andreevich Gromakov was born on 20 December 1946Document Transcript
Yuri Andreevich Gromakov was born on 20 December 1946.
In 1971, he graduated from the Faculty of Aircraft Radioelectronics of the Moscow Aviation
Institute (a technical university).
Until 1994, he worked in various enterprises of the military-industrial complex. From 1992 to 1994,
he was the chief designer of mobile radio systems with a major scientific and technical association.
From 1994 to the present, he has been a Vice-President for Development with Mobile TeleSystems
OJSC, and since 2007 he has been the Director-General of the R&D centre OJSC Intellect Telecom.
He is a Doctor of Technical Sciences and a professor, and has over 100 publications, 22 industrial
patents and three monographs to his name.
His scientific achievements include his work on the creation of convergent telecommunication
networks. He proposed a new means, patented in Russia and the United States, of cellular
communication based on the merging of cellular network resources with a satellite positioning
system, and developed a new topology for cellular communication systems using repeaters with
capacity transfer, thereby reducing the capital and operational expenditure on the creation of a
cellular communication radio system by up to one half. He developed and patented a system for
locating moving objects with an accuracy to within 3 cm which has been brought into commercial
use in Moscow and St Petersburg. In recent years, he has been conducting research in connection
with the development of cognitive radio, and on the basis of those principles has developed a means
of GSM data transfer at a rate exceeding ten megabytes per second.
Yuri Gromakov is a renowned expert in the field of mobile radio systems, satellite navigation and
telematics, having received recognition both in Russia and internationally. His scientific
contribution to the development of mobile communication networks in Russia has involved the
development and implementation of a strategy and principles for the deployment of mobile
communication and data transfer networks, and the theoretical justification and experimental
validation of solutions for the electromagnetic compatibility of radio facilities used in aeronautical
radionavigation and aircraft landing systems with GSM 900 cellular communication system
equipment. He has led and personally participated in work on resolving the scientific and technical
issues associated with the introduction and development of GSM, UMTS, WiMax and other mobile
communication systems, on the development of a master plan for the development of GSM
networks in Russia, on the organization of national GSM roaming, and on the creation of integrated
schemes for terrestrial mobile, satellite and fixed communications.
By a Decree of the Government of the Russian Federation, Yuri Gromakov was awarded the 2003
Prize of the Government of the Russian Federation for his work on the development and creation of
new technologies. He is an Honorary Radio Operator of the Russian Federation, an Academician of
the International Academy of Communications and Vice-President of the National Radio
Doctor of Technical Sciences,
Professor, General Director
OJSC Intellect Telecom R&D centre
A new method for cellular communications
The lead player on the telecommunication stage is now cellular communication. Ever since it first
came onto the scene, the conception and three principles of cellular system construction have
• frequency (code) re-use within cells;
• call continuity thanks to the cell-to-cell handover of the mobile subscriber;
• location of the mobile subscriber by the cellular system.
It is by combining these three principles (Figure 1) that a cellular system and its services are
created. The concept of cellular communication based on frequency re-use to achieve a manifold
increase in the capacity of mobile communication networks was put forward in the 1940s by
AT&T, which in 1968 submitted a report to the United States Federal Communications
Commission (FCC) on future cellular communication systems.
Handover + Communication
None of the aforementioned principles have thus far been changed. All the generations of cellular
communication, from the first (1G) to the third (3G), and even the next generations (LTE and IMT-
Advanced) are based on these three principles.
For many years, the cellular topology, initially geared to the transmission of voice calls, fully
satisfied the interests of users and operators. Then came increasing market demand for higher rates
of data transfer, which could be met by expanding the bandwidth of communication channels, made
possible with the use of higher carrier frequencies for cellular communication. It was just at this
time that the emerging new generations of cellular systems came up against the physical constraints
associated with the implementation of radio interfaces, and against the shortcomings of a cellular
Physical constraints with cellular communication
The capabilities of the radio interface in a cellular system are limited by a number of factors. These
• physical limitations in terms of radio wave propagation distance, and the considerable drop
in communication range as the operating frequency increases (Table 1, Figure 2);
• the negative influence of multipathing when radio waves are propagated in an urban
environment, becoming more pronounced as the frequency increases;
• intersymbol interference in the channel during data transmission;
• increasing negative influence of atmospheric precipitation as the frequency increases;
increasing influence of the Doppler effect with call transmission at higher frequencies;
• real presence of external noise, presence of intrasystem interference, etc.
Frequency Cell Cell
Area ratio Area ratio
MHz (450) (950)
450 50 7850 1.0 0.3
850 30 2826 2.8 0.8
950 27 2289 3.4 1.0
1800 14 615 12.8 3.7
1900 13.3 555 14.2 4.1
2100 12 452 17.4 5.1
Table 1 Figure 2
The aforementioned physical constraints are an objective reality, are essentially insurmountable and
circumscribe the capabilities of cellular communication. It is for this reason that frequencies higher
than 10 GHz remain virtually unused for mobile communications. The use of OFDM and MIMO
technologies in WiMAX and LTE goes some way towards reducing the negative influence of
multipath radio wave propagation.
Shortcomings of cellular topology
As things stand, a cellular network topology (Figure 1) is unquestionably the most effective means
of implementing public mobile communication systems. However, as time goes on its shortcomings
are also becoming ever more apparent:
• the size of cells diminishes with the use of higher frequencies owing to physical limitations
on the radio wave propagation distance, necessitating a higher number of base stations,
controllers and connection circuits;
• smaller cell dimensions necessitate a higher number of handovers as the mobile station
moves around, reducing the likelihood of successful call termination;
• there is an increase in network resource costs associated with the management of
connection, handover, signalling and synchronization processes as the subscriber moves
around an area with small cell dimensions.
Today’s mobile subscribers are not interested in communication standards, their demands having
first and foremost to do with the nature and quality of the available services, their accessibility in
terms of time and location, ease and speed of access to the services, and, of course, their cost.
However, one has to agree that a subscriber's "consumer portfolio" stems from the capabilities of
specific mobile communication technologies. And efforts are currently being made to expand those
capabilities, essentially by means of new types of radio interface and by moving from circuit
switching to packet switching, while not, however, addressing the most fundamental question,
namely that of the principles underpinning the construction and topology of cellular networks.
How does one set about changing the topology of cellular communication in the interests of
enhancing its effectiveness for subscribers and operators? What will bring about a change in cellular
Developing the principles of cellular communication
Let us consider the changes that might occur in cellular communication, the way in which it
operates and its topology, if we were to change one of its three underlying principles (Figure 1) –
for example, the principle of mobile subscriber location.
As things stand, locating a mobile subscriber is effected by the cellular communication system's
own resources. Let us imagine the function of locating the mobile subscriber being transferred from
the cellular network to the mobile station. The cellular network management system no longer has
to concern itself with the task of locating a multitude of active subscribers, either moving around or
stationary at any given moment, and located either within their own network or in the catchment
area of other networks. Using data obtained from a satellite global positioning system (GPS,
GLONASS, etc.), each mobile station determines its own coordinates and transmits them to the
management system via the cellular communication channels. On the basis of the location data
supplied by the mobile station, the network is able to connect the subscriber to other mobile stations
or to subscribers in the fixed telephone network (PSTN). The principles for construction of a
cellular communication system with transference of the subscriber location functions from the
network to the mobile station are shown in Figure 3.
Locating mobile subscribers with the accuracy inherent in a satellite global positioning system
makes for simplification of the cellular communication system infrastructure, resulting in resource
savings, reduced expenditure on network construction and a considerable expansion of functional
capabilities by comparison with the current situation.
Handover + Communication
Satellite global positioning systems (GPS,
Given, moreover, that the new generations of cellular communication, as well as existing 2.5G and
IMT-2000 systems, are moving towards the widespread introduction of new types of service
involving subscriber location, the use of GPS/GLONASS data will help to broaden the range of
services on offer.
Such services include, for example, navigation services, emergency assistance, tourist information,
tracking the location of goods in transit, and so on. Their implementation is made possible by
increasing the accuracy with which the mobile station is located by the cellular communication
network, this being achieved in the case, for example, of GSM or UMTS, by further increasing the
complexity of the cellular communication system and increased expenditure on the hardware and
software resources necessitated by the incorporation of new elements, namely type A location
measurement units (LMUs), connected via the radio interface to the base stations, or type B LMUs,
connected to the base station controller via the cellular A-bis interface, as well as mobile location
centres (MLC). One of these, the serving MLC (SMLC), handles positioning requests, final
calculation of the coordinates and accuracy of the result obtained, while the other, the gateway
MLC (GMLC), performs client support functions (Figure 4).
MSC/VLR service area PLMN service area
MS GSM MSC
BSC VLR MSC
VLR MSC ISDN
External clients of the
The best-known methods for locating a mobile station on the basis of cellular network data are: Cell
ID, for which there is no need to determine the signal strength or delay; Cell ID-TA (timing
advance); TOA (time of arrival); and E-OTD (enhanced observed time difference).
In short, implementation of the above methods of mobile station location, based on the cellular
network’s own resources, calls not only for the installation of additional hardware and software
resources, but also for the assignment of additional connection circuits.
All of this results in continued inefficient exploitation of the cellular network's own resources and
additional expenditure by operators on hardware and software to handle mobile station location by
the network, while the location accuracy is limited to "within the cell”, which can range from a few
hundred meters to tens of kilometres.
As a result of research done to determine the feasibility of implementing principles of cellular
communication system construction based on a transfer of the location function from the network to
the mobile station, with use of the GPS/GLONASS systems, as an integral part of the cellular
network infrastructure, a new method of cellular communication, patented in Russia and the United
States, is proposed.
Use of this innovative approach will serve to enhance the efficiency of the cellular communication
system by increasing its traffic-handling capacity, reduce the burden on the cellular interfaces used
for the transmission of service information (for example, between the mobile station and BTS, BTS
and BSC, and BSC and MSC) and free up network resources for payload transmission, with, at the
same time, a reduction in the volume of cellular communication system hardware and software
resources used for the location of mobile stations (LMUs, SMLCs, GMLCs, etc.) while achieving
greater location accuracy (Figure 5).
A further benefit lies in expansion of the system's functional capabilities through the creation of
cells located at different heights above the Earth’s surface (for example, on different floors of
buildings), as well as in the implementation of vertical handover, the organization of corporate
networks for groups of mobile subscribers within cells, the use of mobile station location data for
forming the maximum of base station multiple-beam antenna radiation patterns in the direction of a
In essence, increasing the efficiency of cellular communication can be achieved by excluding from
the cellular communication method (Figures 1 and 2) the location function that is performed by the
cellular network, and by implementing a cellular communication system incorporating the use of
GPS/GLONASS (or other) resources to handle the location functions within the cellular network, as
well as handover and frequency (code) re-use.
PLMN service area
GSM network MSC/VLR service area
Functioning of the combined cellular communication and satellite positioning system
The communication coverage area is calculated on the basis of a digital ground map, including
features such as building heights and dimensions and road layouts, and a radio wave propagation
model for a range of building conditions and with respect to a given frequency range and allotted
frequency resource. Also taken into account are the predicted channel loadings, communication
reliability and quality requirements, antenna directional characteristics, electromagnetic
compatibility conditions vis-à-vis other radio facilities, handover requirements, and so on. The
calculation results are then used to determine the coordinates, height and parameters of the
communication system base stations.
The cell configuration for each BTS is formed, recorded in electronic form and stored in the
cellular system management centre, from where the data are transmitted and recorded in the BSC
controllers as required for management of the corresponding BTSs. These data, together with the
boundary coordinates, working frequencies (codes) and communication parameters of the
neighbouring cells are used to create a digital ground map in the form of electronic fragments. The
management centre can be set up in the same way as the management centres of existing cellular
communication systems, but equipped with the necessary software for performing all the operations
associated with the communication functions in question.
The mobile station must include the cellular communication terminal, a satellite global positioning
system receiver and a controller for storage and processing of the geographic map data. As it
receives and processes signals from the satellites, it periodically determines its own spatial,
including geographic, coordinates, with the periodicity of that task being adapted (tied) to the speed
at which the mobile subscriber is moving. If the results of two consecutive determinations of the
mobile station’s own coordinates vary considerably, meaning that the mobile subscriber is
travelling at high speed, the interval between determinations will be reduced in order to increase the
When a mobile station first enters the cell of a given base station, the latter sends it a fragment of
the digital electronic map requested from the cellular system management centre. The map shows
the boundary coordinates of the cell in question and those of its neighbours, together with the
working frequencies and codes of the base stations and the communication parameters, with the size
of the digital map fragment being tailored to the speed of travel of the mobile subscriber.
The mobile station periodically compares the positioning data received from the GPS or GLONASS
system with the digital electronic map fragment in order to check with which base station it is
associated. When it moves into a new cell, the mobile station switches to the working frequency or
code, and to the communication parameters, of the base station for the cell in which it is now
The positioning data sent by mobile stations to base stations enable communication to be
established with the mobile stations by means of multipath intelligent antennas. The maximum of
the radiation pattern of one of the antenna beams is lined up directly with the coordinates of the
mobile station and, on the basis of its positioning data, is used to track the movement of that station
The use of precision coordinates for mobile station positioning within the intelligent antenna
management system does away with the need for smooth antenna radiation pattern adaptation
modes on the subscriber side and enables use of a beam switching mode with a fixed "needle-point"
pattern which makes for a shorter call set-up time. The use of switched-beam antennas increases the
communication distance between the mobile station and base station, this being equivalent to
increasing the dimensions of the cell.
Within a single cell (with operation on a single group of frequencies or codes), it is possible to form
microcells with given boundaries determined by geographic coordinates, within which mobile
subscribers can make use of communication parameters – type of radio interface, transmission
speed, communication protocol, tariff, and so on – that are different to those of the cell. Thus, for
example, when a mobile subscriber is located within a microcell, he or she can benefit from various
facilities or additional services.
R1 X2x 2y
micro R 2 2
Determining the location of mobile stations by means of a satellite global positioning system
ensures roaming when a mobile station moves from one communication network into another using
either the same communication standard or different communication standards and types of
radiocommunication. In this case, the coordinates of the boundary cell will correspond to those of
the boundaries of the communication networks in question (particularly where national boundaries
are concerned). A mobile subscriber crossing a national border, or from one cellular communication
area into another, obtains roaming services immediately upon crossing the boundary of the
communication area, unlike what happens with existing cellular networks, where the
communication area and cell boundaries depend on the local radio wave propagation conditions and
cannot in principle be precisely aligned with the network or national boundaries.
Furthermore, by using digital electronic maps and mobile station positioning data obtained from
satellite global positioning systems, with account taken of buildings, BTS system antenna siting
conditions and radio wave propagation models, it is possible to regulate the power level of mobile
and base station transmitters based on the distance between them. According to the load generated
by the mobile stations within a cell, the dimensions and configuration of cells, as well as the
handover conditions, can be remotely set for each mobile station from the cellular system
The high level of positioning accuracy provided by global satellite positioning system data enables
the cellular system to set priorities for access to communication services, impose limitations or bar
any given mobile station from accessing the network. The proposed method for cellular
communication also enables pinpoint or area-based charging (freely configurable by means of pre-
established coordinates) for the communication services on offer to subscribers.
The current positioning data that the mobile subscriber can access worldwide are used for selecting
the desired operator's mobile network and also the types of service required within that network,
based on the settings recorded in the mobile station by the subscriber or operator, with reference, as
the case may be, to the communication service tariffs in force.
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Thus, the new method for cellular communication enhances the effectiveness of cellular
communication systems by incorporating data from satellite global positioning systems into the
Migration to the new cellular network topology can be implemented gradually through the staged
modification of existing networks.
Precision positioning system
One of the first practical steps towards realization of the new method for cellular communication
was the creation of a system for the precise positioning of mobile objects (Figure 7).
This includes the GPS/GLONASS reference stations, which are used in determining the differential
corrections to the coordinate values measured by the GPS/GLONASS receivers in the subscriber
terminals. The differential corrections are calculated as the variation between the coordinates of a
given base station measured at a given point in time (x1, y1) and the actual coordinates of the base
stations (х0, у0) determined by means of precise geodesic methods.
The measured values of an object’s coordinates (x1, y1) contain errors caused by the changing radio
wave propagation conditions between the GPS/GLONASS satellites and the terrestrial receiver. The
value of the differential corrections Δx = (x1 — x0) and Δy = (y1 — y0) remains virtually constant
within a radius of 30 to 40 km from the reference station. Any subscriber (i.e. user of precision
coordinates) located within this area can obtain differential correction values from the computation
centre via the cellular network.
Satellites in the GPS/GLONASS navigation systems
GPS/GLONASS Computing centre
GPS/GLONASS Х1 Y1
30-4 BTS GSM
In the course of researching the feasibility of practical implementation of the proposed method for
cellular communication in conjunction with a precision positioning system, the following results
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• principles were identified for the staged migration of GSM and UMTS cellular networks to
the new cellular communication infrastructure, including combined operating modes and
the use of GSM/GPS and UMTS/GPS terminals with subsequent transition to
• solutions were found to the problems associated with mobile station positioning in
buildings, based on inertial navigation methods using MEMS technology;
• a GPS/GLONASS differential satellite navigation system with a positioning accuracy of up
to 3 cm in real time and geared towards use in conjunction with the proposed cellular
communication system was developed and brought into commercial operation in Moscow
and St Petersburg;
• 3D digital maps and new RF planning methods were developed for the new system
combining cellular communication and differential satellite navigation.
The proposed method for cellular communication is the fruit of research carried out by the Intellect
Telecom R&D centre and the major Russian GSM/UMTS cellular communication operator Mobile
List of abbreviations
MS - Mobile Station
BTS - Base Transceiver Station
BSC - Base Station Controller
MSC - Mobile Switching Centre
VLR - Visitor Location Register
HLR - Home Location Register
OMC - Operation and Maintenance Centre
PSTN - Public Switched Telephone Network
PLMN - Public Land Mobile Network
LMU - Location Measurement Unit
SMLC - Serving Mobile Location Centre
GMLC - Gateway Mobile Location Centre
ToA - Time of Arrival
E-OTD - Enhanced Observed Time Difference
OTDoA - Observed Time Difference of Arrival
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1) ITU-R: Framework and overall objectives of the future development of IMT-2000 and
systems beyond IMT-2000. Recommendation ITU-R M. 1645, June 2003.
2) Gromakov Y.А. Стандарты и системы мобильной радиосвязи (Mobile radio standards
and systems – in Russian) — М.: EcoTrends, 2000. 239 pp.
3) Gromakov Y.А., Severin А.V., Shevtsov V.А. Технологии определения
местоположения в GSM и UMTS (Positioning technologies in GSM and UMTS – in
Russian) — М: EcoTrends, 2005. 144 pp.
4) Patent No. 2227373 (Russia) 20.04.2004. Способ сотовой связи (Method for cellular
communications), Y.А. Gromakov, V.A. Shevtsov
5) Patent No. US 7, 228, 135 B2 (USA) 05.06.2007. Method for Cellular Communications,
Y.A. Gromakov, V.A. Shevtsov.
6) Global Positioning Systems, Inertial Navigation, and Integration. Second edition. Mohinder
S. Grewal, Lawrence R. Weill, Angus P. Andrews. By John Wiley & Sons, Inc., 2007,