A Novel Mechanism for Radio Capacity Maximization
during MBMS Transmissions in B3G Networks
Antonios Alexiou, Christos Bouras, Vasileios Kokkinos, Evangelos Rekkas
Research Academic Computer Technology Institute, Greece and
Computer Engineering and Informatics Dept., Univ. of Patras, Greece
University of Patras, Rio Campus, 26500 Rio, Patras, Greece
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This paper proposes a novel mechanism for efficient power
control during multicast transmissions in Beyond 3rd Generation
(B3G) mobile networks. The mechanism utilizes optimally the
available power resources
Telecommunication System (UMTS) base stations, resulting to
network capacity maximization. The proposed mechanism is
based on the concept of transport channels combination (point-to-
point and/or point-to-multipoint radio bearers) in any cell/sector
of the network in which Multimedia Broadcast/Multicast Service
(MBMS) users are residing. In particular, the transport channel
combination that minimizes the transmission power of the base
station is selected for the transmission of the MBMS traffic to the
corresponding cell. The mechanism is evaluated through several
realistic scenarios and the results indicate the ability of the
mechanism to utilize optimally the radio resources of the network.
Furthermore, our approach is compared with several power
control mechanisms existing in the bibliography, including the 3rd
Generation Partnership Project (3GPP) approaches (presented in
3GPP TS 25.346 and 3GPP TR 25.922), in order to highlight the
enhancements that it provides.
of Universal Mobile
Categories and Subject Descriptors
Architecture and Design – Wireless communication; C.2.3
[Computer-Communication Networks]: Network Operations –
Network Management, Public networks; H.5.1 [Information
Interfaces and Presentation]: Multimedia Information Systems
Design, Management, Performance, Verification.
UMTS, HSDPA, MBMS, RRM, Power Control.
Indisputably, there is a rapidly increasing market for wireless
multimedia applications, such as Mobile TV, that are expected to
face high penetration in future mobile communications industry.
As a consequence, in B3G mobile networks the amount of
multimedia data traffic will surpass the amount of voice traffic. In
order to confront such high requirements for multimedia content,
the MBMS framework was introduced in the Release 6 of the
UMTS architecture. MBMS is a unidirectional service in which
multimedia data is transmitted from a single source entity to
multiple destinations, allowing resources to be shared in an
economical way , . As the term indicates, MBMS consists of
the broadcast and the multicast operation modes.
However, the spread of multimedia data differentiates the current
landscape of Radio Resource Management (RRM) in MBMS and
poses the need for further enhancements. The main requirement
during the provision of MBMS multicast services is to make an
efficient overall usage of radio and network resources. This
necessity mainly translates into improved power control
strategies, since the base stations’ transmission power is the
limiting factor of downlink capacity in UMTS networks. Under
this prism, a critical aspect of MBMS performance is the selection
of the most efficient radio bearer for the transmission of MBMS
multicast traffic. A wrong channel selection may result to a
significant capacity decrease, thus, preventing the mass delivery
of multimedia applications.
In this paper, we propose a power control mechanism for efficient
radio bearer selection in MBMS. The mechanism enhances
MBMS performance in the frame of maximizing radio capacity in
B3G networks. The proposed scheme adopts downlink
transmission power as the optimum criterion for radio bearer
deployment and selects the transport channel combination that
minimizes the transmission power of the base station. Point-to-
Point (PTP) and Point-to-Multipoint (PTM) transmission modes
may be used separately or may be combined and deployed in
parallel. In this way, the mechanism optimally utilizes power
resources and significantly improves radio resources’ allocation.
The paper is structured as follows: In Section 2, we present the
motivation behind our study and the related work in the specific
field. Section 3 is dedicated to an in depth analysis of RRM in
MBMS. Section 4 presents the proposed power control
mechanism, while Section 5 is dedicated to the presentation of the
results. Finally, concluding remarks and planned next steps are
briefly described in Section 6.
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and PTP channels approach, which is essential when the number
of users in the cell increases. However, the reason that our
mechanism has lower power requirements, as shown in Figure 7a,
is twofold. Firstly, it takes advantage of the benefits emerged
through the HSDPA technology, and secondly, it can be
efficiently adapted to any user distribution in any cell, by
selecting one, two or three transport channel simultaneously
(when it is necessary) in order to transmit the MBMS traffic to the
Figure 7. Comparison for variable number of MBMS UEs
6. CONCLUSIONS AND FUTURE WORK
In this paper we presented a novel power control mechanism for
efficient radio bearer selection in MBMS enabled UMTS
networks. The proposed mechanism provides a realistic and
adaptive to dynamic wireless environments approach, by adopting
the concept of radio bearer combination (PTP and/or PTM) in any
cell/sector of the network in order to reduce the power
requirements of the base stations. The mechanism is evaluated
through several scenarios and the results indicated the efficient
operation of the mechanism. In order to highlight the
enhancements provided by the proposed mechanism, we provided
a comparison of the mechanism with approaches existing in the
bibliography, including 3GPP approaches. The main conclusion is
that our mechanism outperforms them, underlining in this way the
necessity for its incorporation in MBMS.
The steps that follow this work could be at a first level the
evaluation of the mechanism through additional simulation
scenarios and at a second level the study of the complexity that
the mechanism inserts in RNCs due to its dynamic and periodic
 3GPP TS 22.146 V8.3.0. Technical Specification Group
Services and System Aspects; Multimedia
Broadcast/Multicast Service; Stage 1 (Release 8), 2007.
 3GPP TR 23.846 V6.1.0. Technical Specification Group
Services and System Aspects; Multimedia
Broadcast/Multicast Service; Architecture and functional
description (Release 6), 2002.
 3GPP TS 25.346 V8.1.0. Technical Specification Group
Radio Access Network; Introduction of the Multimedia
Broadcast Multicast Service (MBMS) in the Radio Access
Network (RAN); Stage 2, (Release 8), 2008.
 3GPP TR 25.922 V7.1.0. Technical Specification Group
Radio Access Network; Radio resource management
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