Mobile Networks Optimization
Mobile Networks Optimization
Purpose of this article is to introduce the process of conducting a Network Performance Audit and Design Review with further Optimization. Mobile Networks Optimization
A Cellular Network or Mobile Network is a wireless network distributed over land areas called cells, each served by at least one fixed-location transceiver, known as a cell site or base station, or even better NodeB.
More specifically, engineers used:
- Base Station to indicate it in GSM technology
- Node B in UMTS
- e-NodeB in LTE
Mobile Networks Optimization: If a mobile cellular network is not performing to its maximum this can directly result in poor performance and in a BAD CE (Customer Experience): dropped calls, insufficient bandwidth causing phones to reduce the audio bandwidth, even barred access, or slow response times for data downloads. As a result, network performance and hence the service quality seen by users is a key differentiation. A good level of perceived quality will help retain users, whereas poor service will lead to high levels of churn for the cellular network operator.
The process described is technology independent and it can use for GSM, UMTS, LTE, Tetra and even Wi-FI or WiMAX Networks. The purpose of such audit is to assess the performance of a network using the full range of available data, and identify aspects of the design and operation of the network that can be improved. An audit will typically result in a series of recommendations and an action plan for network design and performance improvements, along with a process for ongoing performance review and analysis. Mobile Operators has access to enormous amounts of performance data from a wide range of tools and reporting mechanisms available to them. The aim of a performance audit is to focus on those key metrics which are most useful in measuring system performance and to make efficient use of the tools and large quantities of data available.
So, cellular network optimization tools are an essential requirement for any network. They enable a faster response to be gained for performance issues, a better service quality across the network, lower operating costs for the cellular network, and a much more efficient use of capital investment. Accordingly a number of network optimization tools are available on the market, both from network vendors as well as from the independent suppliers. Just look also at our proposal: FOCUS-INFOCOM
Lately some new tools has been presented in the market and they are APP based. Look at our proposal: METRICELL to know more about it. Naturally any tools will need professional people to analyze any recorded data.
The Performance Review is not intended to provide all the answers to all the problems, but to highlight the major issues and provide all the necessary background for further analysis, investigation and in-depth troubleshooting of the major performance impacting problems in the network.
It is important that any network performance audit should follow a methodical process and should be systematic in it’s approach to data collection.
For each of the performance category headings in the outline structure, the following logical process is applied:
- Objective: What parameter are we trying to measure?
- Description: Why are we measuring it and what is the relevance of the measurement to network performance?
- Report Format: How should the measurement be presented, in what kind of graph and what format?
- Interpretation: What are the possible conclusions we can draw from the results?
- Recommendations: Based on our observations and conclusions, what recommendations can we make for solving the problem or for further investigation?
In any cellular network, each cell uses a different set of frequencies from neighboring cells, to avoid interference and provide guaranteed bandwidth within each cell.
When joined together these cells provide radio coverage over a wide geographic area. This enables a large number of portable transceivers (e.g., mobile phones, pagers, etc.) to communicate with each other and with fixed transceivers and telephones anywhere in the network, via base stations, even if some of the transceivers are moving through more than one cell during transmission.
Mobile Networks Optimization
Cellular Network technology supports a hierarchical structure formed by the base transceiver station (BTS), mobile switching center (MSC), location registers and public switched telephone network (PSTN).
The BTS enables cellular devices to make direct communication with mobile phones. The unit acts as a base station to route calls to the destination base center controller.
The base station controller (BSC) coordinates with the MSC to interface with the landline-based PSTN, visitor location register (VLR), and home location register (HLR) to route the calls toward different base center controllers.
Cellular networks maintain information for tracking the location of their subscribers’ mobile devices. In response, cellular devices are also equipped with the details of appropriate channels for signals from the cellular network systems. These channels are categorized into two fields:
- Strong Dedicated Control Channel: Used to transmit digital information to a cellular mobile phone from the base station and vice versa.
- Strong Paging Channel: Used for tracking the mobile phone by MSC when a call is routed to it.
A typical cell site offers geographical coverage of between 15 and 35 Km. The base station is responsible for monitoring the level of the signals when a call is made from a mobile phone. When the user moves away from the geographical coverage area of the base station, the signal level may fall. This can cause a base station to make a request to the MSC to transfer the control to another base station that is receiving the strongest signals without notifying the subscriber; this phenomenon is called handover. Cellular networks often encounter environmental interruptions like a moving tower crane, overhead power cables, or the frequencies of other devices.
Characterize a Mobile Network:
Generally speaking most important parameters to measure are Signal Level and Signal Quality. This parameters have a different name for any technology: GSM, UMTS and LTE.
In order to completely represent a cell site, we need to know:
- Service Technology (GPRS, UMTS and LTE)
- Signal Level
- Signal Interference
- Network latency
- Geographical Position: this is a must in order to know where to go to present some solution to any possible problems
Naturally QoS will be important as well but in a second step.
From all parameters that will be possible measure Engineers will build up a list of KPI to understand the Network Quality.
These KPI are different for any OPCO but there is also a list of Standard KPI form ETSI.
This is the most important parameter, in fact, if it is poor or absent, also the other parameters are spoiled.
The signal level is the signal strength (measured in dBm) received by the mobile phone from the cell site. Depending on various factors, such as proximity to a tower, obstructions such as buildings or trees, etc., the signal strength will vary. As we already told before Signal Strenght assume different name for any technology:
- GSM: RxLev
- UMTS: RSCP
- LTE: RSRP
With serving technology will change also scale to measure it: Good or Poor signal levels are technology dependant!!!
This is the another important parameter and it is directly connected to the Signal Level.
Like the Signal Strenght, it assumes different name for any technology:
- GSM: RxQual
- UMTS: Ec/I0 or Ec/N0
- LTE: RSRQ
Throughput or network throughput is the rate of successful message delivery over a communication channel. This data may be delivered over a physical or logical link, or pass through a certain network node. The throughput is usually measured in bits per second (bit/s or bps), or multiples of this as Mbps, and sometimes in data packets per second or data packets per time slot. The throughput is not to be confused with the channel capacity of the system: both the capacity and throughput are expressed in bit / s, but while the first expresses the maximum transmission rate at which data can travel, throughput is a measure of the actual use of link capacity. The throughput is the amount of data transmitted in a unit time, while the capacity depends exclusively on how much information is available on the channel in the transmission. Like for the Signal level, also for the throughput we used a table with the reference levels to classify the quality of this parameter as we can see in the figure beside. Of course we need of two set of throughput threshold: one for the Download, and one for the Upload.
This parameter is measured mainly by Speed Test, but this measure could be done also in other ways.
Mobile Networks Optimization: Network latency
The Network latency of an internet connection, is the time taken by one or more ICMP packets to reach another computer or server in the network (be it the Internet or LAN). Within the networks the factors that most influence the propagation of the signal are the medium that carries the information and the equipment (for example, switch or router) that the signal crosses in its path. To estimate this time is used the PING.
The PING (Packet Internet Grouper), is a program available on many software platforms which measures the time, in milliseconds, used by one or more ICMP packets to reach another network device (through any computer network based on IP) and go back the origin. It is typically used to verify the presence and reach-ability of another computer on the network and to measure the latency of network transmission.
Mobile Networks Optimization