4G Mobile System: Radio Access Network (RAN) Architecture Development

This report details the development of a Radio Access Network (RAN) architecture for a 4G mobile system, focusing on reducing interference and enhancing network performance. The project involved proposing a new technique for the 4G mobile system, including cell distribution, base station adjustments, carrier frequencies, and channel allocation. A key aspect was replacing the microwave link with a fiber optic system to improve signal strength, quality of service, and data rate. The report also addresses the challenges of managing a large team and implementing the proposed topology, highlighting solutions such as regular meetings and effective leadership strategies. Furthermore, it discusses the importance of addressing Co-Channel Interference (CCI) and Adjacent Channel Interference (ACI) to optimize network capacity and call quality, proposing specifications for a next-generation 4G mobile system with improved capacity, high-speed transmission, and flexible network architecture.

COMPETENCY
DEMONSTRATION REPORT
Career Episode 3

CE 3.1 Project Information
Name of the project: Radio access network (RAN) architecture development for a 4G Mobile
system with reduced interference
Location of the project: [PLEASE FILL]
Project Duration: [PLEASE FILL]
Organization: [PLEASE FILL]
Role and Designation during the time: Team Leader
Execution of the Project
This project was based on the development of Radio Access Network Architecture for
mobile phones. I noticed that mobile communication was spreading and in application in most of
the sectors however, the quality of service, data rate, and signal strength are still not up to the
mark that it could be used as the broad means of communication. I considered it as a challenging
factor as I belong to the same field and I would like to solve issues that can be beneficial for a
very vast population. The 4G technology allowed the individuals to avail the services related to
the connectivity that can allow the audio and video communication. I proposed a new technique
of the 4G mobile system that include the cell distribution and base station, carrier frequencies,
and channel allocation other than the established connection between the new topology with the
application of the fibre optic system. I replaced the microwave link in the air with a cable
connected network topology. I made these modifications in manner to gain the advantages on
better and improved signal strengths, quality of service, and data rate through proposing the
RAN (Radio Access Network) depending upon the fibre length, cluster size, adjacent channel

interferences, and co-channel those have been further reduced. In addition to the development of
the network architecture, I also needed to consider the main issues associated with the network
systems. The major issues that were faced included various types of interferences that caused
various errors and problems in the system. I needed to apply my creative work in order to
counter these issues and develop the system with minimized errors and problems.
I was chosen as the leader of the team and hence, it was my responsibility to develop a
feasible set of objectives that could be followed by the individuals in the team in manner to
accomplish the goals pf the project. I introduced the following objectives throughout the report:
o To enhance the network strength of the 4G network
o To increase the flow and exchange of the data rate
o To improve the quality of service being introduced to the 4G users
o To use the fibre optic cables for replacing the existing network topology
o To propose the RAN for eliminating the existing problems in the 4G network
As the leader of the team, I handled my own duties as well as assisted my team mates in
bypassing the challenges and obstacles that came our way during the course of the project. I also
led my team to take up such challenges and apply personal creative ideas that helped to solve the
challenges instead of reporting to the supervisor for help.
Area of Work: In this project, I was involved as a telecommunication engineer and
hence, I needed to focus on the duties that were related to my field of study. During the entire
course of my study, I needed to be involved in gaining technical knowledge and in this project, I

applied the knowledge and skills gained. In addition to the defined project works and duties, I
also needed to show creative ideas in order to ensure high quality outcome in the project. In
addition, I had to assure that the entire team is motivated and delivering the necessary objectives
of the project and contributing in the idea of improving 4G network through effective
cooperation. I kept a friendly relationship among the team for assuring their reliability on me. I
had to analyse the existing mobile system through analysing the co-channel and adjacent channel
interference and propose a 4G channel carrier frequency and channel allocations. I assigned the
carrier frequencies and channel allocation as described in the following table:
System Downlink
frequency
band (MHz)
Uplink
frequency
band (MHz)
Channel
spacing
(kHz)
Bandwidth
(MHz)
Duplex
distance
(MHz)
No. of
channels
E-GSM900 925 to 960 880 to 915 200 35 45 175
P-GSM900 935 to 960 890 to 915 200 25 45 125
GSM1900 1930 to 1990 1850 to 1910 200 60 80 300
GSM1800 1805 to 1880 1710 to 1785 200 75 95 375
LTE 2300 to 2360 2110 to 2170 5000 60 190 12
UMTS 2110 to 2170 1920 to 1980 5000 60 90 12
In addition to these, I also need to report to the supervisor at the end of each week so that he can
be able to monitor the progress of the objective. I asked my team mates to produce a daily log at
the end of each project day. At the end of each week, I compiled the log, prepared a progress
report and sent it to the project supervisor for checking.
Following is the architecture of the team involved throughout the project:

Figure 1: Team Member associated in this project
The following spectrum was gained through the proposed carrier frequencies and channel
allocation:

Figure 1: ACI effect on the transmitted signal power spectrum (8PSK) modulation
Project Responsibilities: As a leader of my team, I had a number of different
responsibilities including performing my own duties in the project as well as guiding my team
members throughout the course of the project. When the project was first assigned, I created a
work breakdown structure of the project duties and allocated the work packages to my team
members according to their skills and interest. I was responsible for proposing the best strategy
and topology that can allow the 4G users to avail the best services related to the network
application. I had to efficiently introduce the RAN as an option of topology for replacing the
existing microwave link topology and enhancing the respective deliveries of the 4G network. I
had to assure that proposes modification fulfils the advanced needs and requirements of the
users.
Theory of the Project: The existing system of 4G had many lagging factors those were
leading to the less satisfactory services to the users and hence, transformation was necessary for
the improvement of the existing system. I proposed the new technique for the 4G mobile system
in manner to enhance the network strength and data exchange rate through the introduction of
new cell distribution and base station, carrier frequencies and channel allocation. I proposed the
new network topology that can replace the existing microwave link interface with the fibre optic
system that can allow the enhancement in the respective constraints. I introduced the approach
that will be helpful in enhancing the quality of service, data exchange rate, and signal strength
through the application of the RAN. The length of the fibre cable will be depending upon the
adjacent channel and cochannel interferences, and or cluster size. I made the following
modifications for the coverage planning and the fibre length:

Sub-
band
no.
Downlink
frequency band
(GHz)
Uplink frequency
band (GHz)
No. of sub-
channels
Sub-band band
Width (MHz)
Channel
spacing
(MHz)
1 2.3 to 2.5 2.0 to 2.2 40 200 5
2 2.9 to 3.1 2.6 to 2.8 40 200 5
3 3.5 to 3.7 3.2 to 3.4 40 200 5
4 4.1 to 4.3 3.8 to 4.0 40 200 5
5 4.7 to 4.9 4.4 to 4.6 40 200 5
6 5.3 to 5.5 5.0 to 5.2 40 200 5
7 5.9 to 6.1 5.6 to 5.8 40 200 5
8 6.5 to 6.7 6.2 to 6.4 40 200 5
9 7.1 to 7.3 6.8 to 7.0 40 200 5
10 7.7 to 7.9 7.4 to 7.6 40 200 5
Applied Engineering: I proposed a simplified 4G RAN architecture that can be helpful
in meeting the objectives of the project as mentioned in the following diagram:
Figure 2: Simplified 4G RAN architecture
I calculated the CCI for the two channels of the GSM system those have been separated
by 200 kHz, that would be resulting in the impact over the signal quality by ACI without cell
planning. The CCI can be expressed as:

Where PC= wanted signal power
PT= signal power from the interfering transmitter
i) The GSM specification recommends that the C/I ratio should be greater than 9 dB
ii) Ericsson recommends that 12 dB should be used as the planning criterion
iii) Operators generally plan for higher C/I value
ACI can be expressed as follows:
Where, = PC power from a wanted signal
PA= power from an adjacent channel
iv) The GSM specification states that the carrier-to adjacent (C/A) ratio must be greater than –9
dB
v) Ericsson recommends that a C/A ratio higher than 3 dB should be used as the planning
criterion.
CE 3.3.3 Identified issues and their solutions
3.3.3.1 Issues
I identified that the management of the team was a serious problem for me as I was
handling a big team under my guidance and the results were going to impact on a very large

group. The implementation of the proposed topology was another challenging factor that would
need a large human force for the successful and efficient delivery. Management and leadership
was crucial and someone needed to take the stand as the team was being scattered and it was at
the verge of failure. The project needed proper and effective leadership and management
strategies in manner to deliver the necessary objectives and goals of the project.
3.3.3.2 Solutions
I introduced a regular meeting process in which every individual was open to discuss any
matter including project related or personal affairs. This helped the individuals in creating a bond
among each other to understand the facts. The bonding between the team members helped in
delivering the necessary objectives and goals of the project. I took the stand of developing an
effective set of strategies those could allow the proper and effective strategies in manner to
manage the entire team and their roles throughout the project.
CE 3.3.4 Plan to produce creative and innovative work with collaboration
The existing network topology was not efficient enough to deliver the needs and
requirements of the users and hence, I introduced the replacement of the existing network with
the RAN and introduced a new topology that is far better efficient and effective than the existing
system. During my work in the project, I found out that Co-Channel Interference (CCI) is a
major interference in mobile systems that is caused by spectrum allocations of frequency reuse
when sufficient optimization is not applied on frequency planning. I also found out that the ration
of carrier-to-interference (CI) powers was decreased at the periphery of the cells due to the CCI.
As a result of this, the system capacity was also reduced and in turn, band-offs are frequent and
the call drops are much more experienced during an ongoing call connection. I conducted a

detailed study on the same and found out that there are certain specifications of GSM that ensure
the interference is not encountered. These specifications are follows.
i) The GSM specification recommends that the C/I ratio should be greater than 9 dB.
ii) Operators generally plan for higher C/I values.
iii) Ericsson recommends that 12 dB should be used as the planning criterion.
iv) Ericsson recommends that a C/A ratio higher than 3 dB should be used as the
planning criterion.
v) GSM specification states that the carrier-to-adjacent (C/A) ratio must be greater than –
9 dB.
Considering these factors, I proposed a number of features that are applicable for the
development of a 4G mobile system that will replace the 3G mobile systems. The specifications I
developed were as follows.
i) Larger capacity (~10 times greater than 3G systems).
ii) High-speed transmission (peak of 50 to 100 Mb/s and average of 200 Mb/s).
iii) Next-generation Internet support (IPv6, QoS).
iv) Use of microwave band (2 to 8 GHz).
v) Flexible network architecture.
vi) Seamless services.
vii) Low system costs (1/10~1/100 of 3G systems).

In addition, during the course of development of the architecture, I determined that the
proposed band to be used for the 4G connection should be between 2 to 8 GHz. I also determined
that since high frequency carriers will be used, the coverage of the base stations will be much
smaller than those of 3G connection. Hence, I deduced that in order to have the same total
coverage area of 3G connection, more base stations will have to be set up for the 4G network but
this also will cause large interference for both CCI and ACI.
There were different members from different background and culture within the team and
we had to work on the single project. I managed to make good relationship to others and tried to
listen everyone while making decision. The project was delivered only because of the
contribution of every team member associated in the team. I was leading the project under the
guidance of supervisor and there were many individuals under me and I assured that every
individual under me play a cooperative role and deliver the necessary objectives of the project.
the project would have never been completed without the contribution of the team members
involved in the project.
CE 3.4 Project Review
CE 3.4.1 Project Overview
I proposed a new topology for the bottom station connection outcomes in reduced loose
area losses and a development in sign energy, although, the set-up value is excessive the usage of
this proposed approach, but the walking value is very low due to the fact fibre optic device
running value is low. However, microwave link machine has very excessive set up and strolling
fee. Additionally, I tried to manage the sustainability as the surroundings outcomes on
microwave hyperlink, but fibre optic hyperlink is under floor, so the environment effect is

negligible. Improved that for the equal pattern place, the wide variety of BSs for 3G is 13, whilst
that for 4G is 36 (this is approximately three instances that of 3G). This is due to the better
frequency bandwidth for 4G cell, resulting in a smaller mobile radius.
CE 3.4.2 Future Scope of Work
When I was working on this particular project, I determined that there is a lot of scope for
further upgrades and improvement and thus, the future scope of work for this topic is
significantly bright. Since mobile telecommunication is a very popular mode of communication
between two or more people in the current world, it is expected that the telecommunication
system will also undergo rapid changes and improvements to suit the growing needs and
demands of the customer. For instance, after the 3G technology, 4G technology was rapidly
developed and rolled out for the customers for using high speed internet and calling processes.
Again, 5G technology is being developed at a lightning pace that will bring even better internet
speeds and calling features. Thus, it can be easily said that this particular topic will always be
under constant development and the future scope of study will continue to be expanded due to
the growing needs and demands of the customer.