FACULTY OF ENGINEERING AND SUSTAINABLE DEVELOPMENT
.
MODULATION CODING IN A RADIO LINK AND DATA
TRANSFER APPLICATION USING L2 VPN ETHERNET
OVER MPLS IN A LARGE NETWORK
MSc Thesis
Doğan VARLI
September 2015
Master’s Thesis in Electronics
Master’s Program in Electronics/Telecommunications
Examiner: Dr. JOSẺ CHILO
SUSTAINABLE DEVELOPMENT
MODULATION CODING IN A RADIO LINK AND DATA
TRANSFER APPLICATION USING L2 VPN ETHERNET
OVER MPLS IN A LARGE NETWORK
Doğan VARLI
September 2015
Master’s Thesis in Electronics
This thesis work has been submitted to Högskolan I Gävle Electronics/Telecommunications department in order to fulfill the requirement of completing 30 ECTS credit for the degree of MSc in Telecommunications
Preface
Abstract
In this thesis work, the locations where we are unable to reach via fiber are considered for wireless transmission links. In the practical part of this thesis different modulation techniques and antenna sizes were analyzed in order to provide the most efficient way of data transmission. The data between this wireless links was transfered using MPLS L2 VPN solution.
According to improving technology and increasing internet usage, the communication speed, which is between users and providers, becomes more inevitable for transmitting data without any delays. More than one users might use same connection line for transmitting their packets and it is able to be caused an online traffic and some delays and data loss could occur. In this circumstance, high rate internet demands would lead extra costs for Internet Service Providers (ISPs) and users.
In the introduction part, a brief description for the history of communications and basic equipments for Radio Link and Fiber Optic cable are done.
In the theory part, detailed information was provided about modulation techniques and multiplexing techniques followed by general information about computer networks and comprehensive information about OSI layers.
In the process and result parts, program outputs for Path Loss design which was used for R/L was mentioned in a detailed way. After that, Ethernet Over MPLS L2 VPN was highlighted and a simulation from point-to-point "Ethernet Over MPLS L2 VPN” was conducted in GNS3 software. Furthermore, the simulation for point-to-multipoint case was then applied in a laboratory environment in order to achieve the desired result.
In the result part, different R/L simulation results are compared to determine the optimized modulation technique and antenna sizes which could then be merged with simulation results from the previous part.
Keywords: Radio Link, Path loss, GNS3, VPN, QAM, MPLS (Multi-Protocol Label Switching),
Table of Contents
Preface ... iv
Abstract ... v
1.INTRODUCTION ... 14
1.1 BASIC EQUIPMENTS OF COMMUNICATION SYSTEMS ... 14
1.2 FIBER OPTIC COMMUNICATION ... 15
1.3 PROPOSE OF THESIS ... 16
1.4 METHOD USED ... 16
2. THEORY ... 17
2.1 MODULATION... 17
2.1.1 ANALOG MODULATION ... 18
2.1.2 QUADRATURE AMPLITUDE MODULATION (QAM) ... 18
2.2. MULTIPLEXING ... 24
2.2.1. TIME DIVISION MULTIPLEXING ... 24
2.2.2. FREQUENCY DIVISION MULTIPLEXING ... 25
2.2.3. WAVELENGTH DIVISION MULTIPLEXING ... 27
2.3. CLASSIFICATION OF COMPUTER NETWORKS ... 27
2.3.1. LOCAL AREA NETWORK ... 27
2.3.2. METROPOLITAN AREA NETWORK ... 28
2.3.3. WIDE AREA NETWORK ... 28
2.4. ISO-OSI REFERANCE MODEL ... 29
2.4.1 PHYSICAL LAYER ... 29
2.4.2 DATA LINK LAYER ... 30
2.5.1. STATIC ROUTING PROTOCOL ... 31
2.5.2. DYNAMIC ROUTING PROTOCOL ... 32
2.5.2.1 OPEN SHORTEST PATH FIRST (OSPF) ... 33
2.5.2.2 EIGRP ... 34
2.6 VIRTUAL PRIVATE NETWORK (VPN) ... 35
2.7 MULTI PROTOCOL LABEL SWITCHING (MPLS) ... 35
2.7.1 MPLS ARCHITECTURE AND BASIC COMPONENTS ... 36
2.7.1.1 MPLS LABEL ... 36
2.7.1.2 LABEL CHANGES ... 37
2.7.1.3 LABEL SWITCHING ROUTER (LSR) ... 38
2.7.1.4 LABEL SWITCHED PATHS (LSPs) ... 38
2.7.1.4.1 HOP BY HOP ROUTING ... 38
2.7.1.4.2 EXPLICIT ROUTING ... 39
2.7.1.5 FORWARDING EQUIVALENCE CLASSES (FEC) ... 39
2.7.2. LABEL DISTRBUTION PROTOCOL (LDP) ... 39
3
PROCESS AND RESULTS ... 41
3.1. RADIO LINK DESIGN BY USING PATHLOSS PROGRAM ... 41
3.1.1.1 DESIGN SIMULATION -1 ... 46
3.1.1.2 DESIGN SIMULATION -2 ... 49
3.1.1.3 DESIGN SIMULATION -3 ... 52
3.1.1.4 DESIGN SIMULATION -4 ... 55
3.1.1.5 DESIGN SIMULATION -5 ... 58
3.2 L2 VPN ETHERNET OVER MPLS ... 62
3.2.1. POINT TO POINT L2 VPN ETHERNET OVER MPLS IN GNS3 ... 62
3.2.1 MULTIPOINT L2 VPN ETHERNET OVER MPLS IN LABORATORY ... 65
3.2.1.1 MULTIPOINT ETHERNET OVER MPLS L2 VPN WITHOUT L2 SWITCH .. 65
4 DISCUSSION ... 73
5 CONCLUSIONS ... 74
List of Figures & Tables
Figures
Figure 1.1 The equipment used in a communication system
14
Figure 1.2 The basic equipment of a radio communication system
14
Figure 1.3 The basic equipment of optical communication system
15
Figure 2.1 The scheme of modulation techniques
17
Figure 2.2 Modulation Method for Digital Data
18
Figure 2.3 QAM Modulator Architecture
20
Figure 2.4 QPSK, 4-QAM (Gray coded)
21
Figure 2.5 16-QAM (Gray coded)
21
Figure 2.6 64-QAM (Gray coded)
22
Figure 2.7 256-QAM
23
Figure 2.8 TDM Multiplexing
24
Figure 2.9 TDM Block Diagram
25
Figure 2.10 TDM formation with Two PAM signal
25
Figure 2.11 FDM Multiplexing
26
Figure 2.12 FDM Block Diagram
26
Figure 2.13 160 λ has the capacity to example WDM transmission
27
Figure 2.14 OSI Reference Model
29
Figure 2.15 Dynamic Routing Protocol Examples
32
Figure 2.16 Dynamic Routing Protocol structure
33
Figure 2.17 Formation of MPLS
36
Figure 2.18 MPLS Label Format
37
Figure 2.19 Formation of LSR
38
Figure 3.1 Link Definitions in Path Loss
43
Figure 3.2 Generating Path Profile and terrain data for Site 1
43
Figure 3.3 Generating Path Profile and terrain data for Site 2
44
Figure 3.4 Clutter Backdrop and terrain data
44
Figure 3.5 Terrain data
45
Figure 3.6 Antenna Heights
45
Figure 3.7 Transmission Analysis 1
47
Figure 3.8 Transmission Analysis for Antenna 1.8m
47
Figure 3.9 Transmission Analysis 2, Pathloss Calculation with 1.2m Antenna
50
Figure 3.10 Transmission Analysis 2 for Antenna 1.2m
50
Figure 3.11 Transmission Analysis 3, Pathloss Calculation with 0.6m Antenna and 64 QAM modulation
53
Figure 3.12 Transmission Analysis 3 for Antenna 0.6m an 64 QAM modulation
53
Figure 3.14 Transmission Analysis 4 for Antenna 0.6m and 16 QAM modulation
56
Figure 3.15 Transmission Analysis 5, Pathloss Calculation with 0.6m Antenna and 4QAM modulation
58
Figure 3.16 Transmission Analysis 5 for Antenna 0.6m and 4 QAM modulation
59
Figure 3.17 Point To Point Ethernet Over MPLS L2 VPN
63
Figure 3.18 CDP Neighbourship between R2 and R4
63
Figure 3.19 EIGRP Neighbourship between R2 and R4
64
Figure 3.20 Ethernet Over MPLS L2 VPN application
65
Figure 3.21 Cisco ASR9010 Picture And Cards
66
Figure 3.22 L2 Switch
67
Figure 3.23 Generated Pseudowires Tunnel between Sites
67
Figure 3.24 Site 2-PC-2 to Site 1-PC-1 Reaction time
68
Figure 3.25 Site 2-PC-2 to Site 3-PC-3 Reaction time
68
Figure 3.26 Site 2-PC-2 to Site 4-PC-4 Reaction time
69
Figure 3.27 Site 2-PC-2 to Site 5-PC-5 Reaction time
69
Figure 3.28 Ethernet Over MPLS L2 VPN application Link Failure Site 2 to Site 3
70
Figure 3.29 Site 2-PC-2 to Site 1-PC-1 Link Failure
70
Figure 3.30 Site 2-PC-2 to Site 3-PC-3 Link Failure
71
Figure 3.31 Site 2-PC-2 to Site 4-PC-4 Link Failure
71
Figure 3.32 Site 2-PC-2 to Site 5-PC-5 Link Failure
72
Figure A-1 Radio and Antenna Model
A1
A1
1
Figure A-2 Transmission Analysis for rain loss
A1
Figure A-3 Transmission Analysis for path profile data
A2
Figure A-4 Radio Specification for 256QAM
A2
Figure A-5 Radio Specification for 16QAM
A3
Tables
Table 2.1 Bandwidth efficiency limit of the modulation types
23
Table 3.1 Design 1 Result
48
Table 3.2 Design 2 Result
51
Table 3.3 Design 3 Result
54
Table 3.4 Design 4 Result
57
Table 3.5 Design 5 Result
60
Table 3.6 R/L Total Result
61
Abbreviations
AM : Amplitude Modulation ATM : Asynchronous Transfer Mode BGP : Border Gateway Protocol CoS : Class of Service
CDP : Cisco Discovery Protocol
DHCP : Dynamic Host Configuration Protocol DWDM : Dense Wavelength Division Multiplexing EIGRP : Enhanced Interior Gateway Routing Protocol FDDI : Fiber Distributed Data Interface
FDM : Frequency Division Multiplexing FEC : Forwarding Equivalence
FM : Frequency Modulation FR : Frame Relay
FTP : File Transfer Protocol HDLC : High Level Data Link Control HTTP : Hyper Text Transfer Protocol
IEEE : Institute of Electrical and Electronics Engineers IETF : Internet Engineering Task Force
IGRP : Interior Gateway Routing Protocol IP : Internet Protocol
ISDN : Integrated Services Digital Network
ISO : International Organization for Standardization ITU : International Telecommunication Union ITU-T : ITU Telecommunication Standardization Sector LAN : Local Area Network
LDP : Label Distribution Protocol LER : Label Edge Router
LIB : Label Information Base LLDP : Link Layer Discovery Protocol LSP : Label Switching Path
OSPF : Open Shortest Path First PAM : Pulse Amplitude Modulation PM : Phase Modulation
PVC : Private Virtual Circuits
QAM : Quadrature Amplitude Modulation QoS : Quality of Service
QPSK : Quadrature Phase Shift Keying R/L : Radio Link
RIB : Routing Information Base RIP : Routing Information Protocol RSVP : Resource Reservation Protocol SDH : Synchronous Digital Hierarchy SMDS : Switched Multimegabit Data Service SMTP : Simple Mail Transfer Protocol SNMP : Simple Network Management Protocol SSB : Single Side Band
TCP : Transmission Control Protocol TDM : Time Division Multiplexing TFTP : Trivial File Transfer Protocol TTL : Time To Live
VPN : Virtual Private Network WAN : Wide Area Network
1.INTRODUCTION
In the introduction part, simulations used in this project and general logics of communication systems and fiber communications are briefly discussed. Furthermore, the modulation techniques used in Radio Link simulation design and functions of MPLS mechanism are mentioned.
1.1 BASIC EQUIPMENTS OF COMMUNICATION SYSTEMS
It is necessary that, to form an information, electronic signals firstly must be converted to electrical format in non-optical system. This process takes place by means of a converter, which converts the audio or data to electrical signals and the level of this signal are powered by the help of the equipped amplifiers and transmitted via a transmission line from one point to another. After this process, considering the losses in the level of this signal, the signal is strengthened again and the received signals are converted into voice or data signals via a converter. In Figure 1.1 some basic equipments are shown for an example of communication system. [1]
Figure 1.1 The equipment used in a communication system [1]
The radio link systems are used for transportation of information from one point to another without using a cable. As shown in Figure 1.2 a receiver and a transmitter is necessary to transfer the information in radio link systems. In both figures, electronic noise disrupts the signal which are the unwanted effects for the process and they are needed to be minimized during the system design.
Figure 1.2 The basic equipment of a radio communication system [1]
1.2 FIBER OPTIC COMMUNICATION
Copper cables does not meet demand for high speed, due to this, there is an increase in the use of fiber optic systems and communication tools and they become a medium of equipments that provides higher quality service. By using light as the information carrier in such systems, high capacity and low losses for information transportation, fiber optic communication expands through the world and constitutes a main element for the communication infrastructure.
There is an increase by means of usage of fiber optic cable and amount of transferred data. The increase in the internet usage and data usage, and for the effective and fast transportation of audio and image traffic through optic data way a device named SDH (Synchronous Digital Hierarchy) was developed which uses TDM multiplexing technology. It provides data transportation in different speeds without changing the existing fiber infrastructure it was planned to increase the capacity of sending data and using wavelength Division Multiplexing WDM (wavelength Division Multiplexing) method Tbit/s speeds have been achieved.
Figure 1.3 The basic equipment of optical communication system [3]
Fiber optic communication systems also consist of transmitter, communication channel and receiver. Figure 1.3 is an example of optic communication system. It consist of transmitting circuit, driver circuit and light source and its objective is to transmit the electrical signal to the light signal and transfer it to the fiber optic cable. For the light source, LED and semi-conductor lasers are used.
Optic communication channel is used for the transport the signal without any disruption. Atmosphere is used as a communication medium and this called "Free Space Optic". By using fiber optic cable as a medium of optic communication channel, a huge amount of information can be transferred to the long distances and losses are minimized in fiber optic cables.
1.3 PROPOSE OF THESIS
In this thesis work, wireless transmission links were considered for the locations which were unreachable via fiber. By this way the user sites were connected to MPLS backbone. In the practical part of this thesis different modulation techniques and antenna sizes were analyzed in order to provide the most efficient way of data transmission. The data between these wireless links was transfered using MPLS L2 VPN solution.
The aim of the thesis is to provide the highest throughput between R/L locations using available modulation techniques. In order to do this, a simulation named PathLoss was used where one can take different parameters into consideration, such as modulation tehnique and antenna size and than can model a formula. So the idea is to find the best correlation of the parameters for the objective of providing the best service to the computers in R/L designed locations and other locations as if they were on the same network using Ethernet over MPLS L2 VPN application. In addition, the costs can be minimized using this solution. In this case, an emerging technology which is called Multi-Protocol Label Switching (MPLS) is used for minimization of the costs. This protocol has a labelling technology which enables routers to forward the incoming packets by using tunneling mechanism.
1.4 METHOD USED
Path loss test tool and modulation techniques for 256 QAM, 64 QAM, 16 QAM and 4 QAM have been used in order to perform simultaneous simulations so that best correlation of stated variables are characterized for the project. The variables are then simulated with various antenna sizes for the best throughput of 155 Mbit/s data transfer.
2. THEORY
In this part, modulation techniques, Quadrature Amplitude Modulation types which is especially used in R/L design in thesis, multiplexing techniques, classification of computer networks, routing protocols and MPLS labelling protocols were described.
2.1 MODULATION
Modulation is the event that low frequency signal (information) is superimposed to a high frequency signal carrier to send long distance in order to transmit information signal to a more suitable transformation shape. [5] Modulation type is chosen by considering existing noise, transmitter power and bandwidth. The feature of the carrier signal can be changed according to the modulation signal. This signal is called as modulated signal. In Figure 2-1, modulation techniques are given under two title and in Figure 2-2 the modulation techniques for digital data are given.
Figure 2.2 Modulation Method for Digital Data
In this part modulation multiplexing techniques are given and a brief description about amplitude modulation and phase modulation from Analog modulation techniques. Furthermore, a comprehensive description is given about QAM modulation used in R/L design.
2.1.1 ANALOG MODULATION
It can be inferred that two reasons are important for the modulation of analog data over analog signals. Firstly, it is possible that the needed data may be different for transmission. Without modulation, it is not possible to transmit baseband signals in wireless transmissions. The other reason is that frequency division multiplexing can be applicable in analog modulation so that, by modulating them, data can be transferred by different uses over different bands.
2.1.2 QUADRATURE AMPLITUDE MODULATION (QAM)
Basically, in Quadrature Amplitude Modulation technique, QPSK (4QAM), 16QAM, 64QAM and 256QAM techniques were used to introduce R/L simulation activities and here the main principles of these techniques are described and QAM architecture was explained.
Compared to the some low efficient modulation shapes, QAM is able to provide, high data ratio with a mid-level application complexity and high spectrum efficiency. Linear modulation forms provides, high bandwidth and power efficiency thus, it can be used frequently in wireless communication. In mobile and cellular systems m-QAM modulation as a two dimensional modulation type, provides the necessary high speed service. [6,8]
MODULATION METHODS FOR DIGITAL DATA
TRELLIS CODED MODULATION
PHASE SHIFT KEYING (PSK) QUADRATURE AMPLITUDE MODULATION (QAM) CONTINUOUS PHASE MODULATION GAUSSIAN MINUMUM SHIFT KEYING (GMSK) MINIMUM SHIFT KEYING (MSK) CONTINUOUS PHASE FREQUENCY SHIFT KEYING (CPFSK) FREQUENCY MODULATION FREQUENCY SHIFT KEYING (FSK) PHASE MODULATION
PHASE SHIFT KEYING (PSK)
DIFFERENTIAL PHASE SHIFT KEYING (DPSK)
As shown in Figure 2-3; and are calculated by simultaneously applied both information flow {an} and k-bit signal over on two upright carriers. And this achieved modulation is called Quadrature
Amplitude Modulation and the signal is expressed as follows [8]
(2.4)
Here, and
=
tan−1QAM modulation signal wave form is a combination of
amplitude and phase modulations.
The signal wave forms of QAM Modulation, was shown as a linear combination of the wave type which are and . When put into the formulas (2.5) and (2.6) the complex baseband signal can be derived as in mentioned in Figure 2-3. [8]
Eg the energy of signal impact
Figure 2.3 QAM Modulator Architecture [9]
M-QAM describes the bit number for each star (point) within the QAM star diagram. In the context of this thesis, a simulation for QAM techniques for Nbps = 2, 4, 6, 8 and M= 4, 16, 64, 256 was conducted. For M, the formula in 2.7 is applicable which describes Nbps as a symbol
The formula applies in 2.7 for M which is the alphabet number of QAM modulation and represents the number of bits transmitted per symbol. In Table 2.1 the speeds for QAM modulation types are shown
: Symbol of the number of bits Number of QAM modulation alphabet
In order to minimize the errors resulted during code solving in QAM modulation and minimizing the frequency bandwidth, Gray coding is using for this process. In gray coding, in each time only one change of a bit is permitted for modulation levels. In Figure 2-4, which can be seen in the modulation of QAM-QPSK that each star includes a value of 2 bit for a total of 4, there is a jump from 00 value to 01 or 10 not 11.
Star diagrams of modifications are shown in Figure 2-5 which each star includes a value of 4 bits whit a total of 16 QAM, in Figure 2-6 which each star includes a value of 6 bits whit a total of 64QAM, in Figure 2-7 which each star includes a value of 8 bits whit a total of 256QAM.
Figure 2.4 QPSK, 4-QAM (Gray coded)
Figure 2.7 256 QAM
Modulatıon Format
Theoretıcal Bandwıdth Efficiency
limits
MSK
1 bit/second/Hz
BPSK
1 bit/second/Hz
QPSK
2 bit/second/Hz
8PSK
3 bit/second/Hz
16QAM
4 bit/second/Hz
32QAM
5 bit/second/Hz
64QAM
6 bit/second/Hz
256QAM
8 bit/second/Hz
2.2. MULTIPLEXING
It became an important necessity to increase the capacity of transmission lines from the beginning of the communication. The aim of the multiplexing is transferring multiple voice or image data simultaneously. It is not efficient to transfer only a voice or image data information in an electrical or optical transmission line because it is not only a costly procedure but also it is a waste of high capacities for only one user.by multiplexing, multiple data can be transmitted simultaneously or one by one. Some techniques can be used in order to share this transmission line to users. These are: Time Division Multiplexing (TDM) and Frequency division multiplexing (FDM). [5]
2.2.1. TIME DIVISION MULTIPLEXING
In TDM, a time period is determined for every user thus, transmission time can be shared for all users. TDM is a multiplexing type which transfer two or more information in a communication channel to the sub channels simultaneously. This means that, it divides the space into particular time periods and uses different time period for each numerical sign. The time situation of TDM was shown in Figure 2-8.
Figure 2.8 TDM Multiplexing
In Time Division Multiplexing, the whole bandwidth was engaged to each channel with a regular time periods. In order to avoid an overlap during the multiplexing of signs with TDM in time level, it is necessary that, the sampling frequency of signs should be an integer of each other. Each receiver should know the arrival time of the sign thus, a synchronization between receiver and transmitter is necessary. [5]
Figure 2.9 TDM Block Diagram
The Time Division Multiplexing can be used by pulse amplitude modulation (PAM). N number of signals are modulated in right periods and can be sent from one channel. In Figure 2-10, a TDM signal structured by two signals can be seen. X1(t) and X2(t) signals represent the samples from different time periods. . [11]
Figure 2.10 TDM formation with Two PAM signal
2.2.2. FREQUENCY DIVISION MULTIPLEXING
Figure 2.11 FDM Multiplexing
An information signal is transmitted from point to point by using a communication line. This communication line can be a line just like in a phone communication line or in space just like for the communication of radio or television. The bandwidth of the signal which is meant to be sent is generally represents a small area of the transmission line’s bandwidth. Due to this, it is a waste to send just a signal through a transmission line. Furthermore, it is not possible to send multiple signals which cover same frequency bandwidth through a single transmission line. It is hard to separate these signals by receiver. So, this problem can be solve in this way: the frequency circles of the signals that covers the same frequency bandwidth need to be switched the same frequency bandwidth. Thus, the signals that does not cover the same frequency bandwidth is going to be derived [1].
In figure 2.12, a FDM multiplexing diagram was shown.[7] When looking to the spectrum of the signal, it can be seen that there are frequency number as much as number of message sent. Signals are filtered and according to the signal type, a demodulation is applied and the message obtained by receiver.
2.2.3. WAVELENGTH DIVISION MULTIPLEXING
Wavelength division multiplexing (WDM) is a method of signal multiplexing at different wavelength over fiber. During processing, virtual fibers which have different carrying signal capacities are generated. It might be considered that WDM system is a set of parallel optical transmission channels which uses the different wavelength of each lights but shares same transmission line. WDM network consists of different optical channel paths. In other word, each the lights of channel are composed different color. A simple example WDM structure is shown in Figure 2.13. WDM systems, that are designed to supply the demand of higher bandwidth level in terabits, increase the capacity of existing network without any needs for rewiring. WDM can operate only two channels that are either the two wavelength of 1310 and 1550 nm or 850 and 1310 from a pair of fiber.[12]
In dense wavelength multiplexing divide (DWDM), the wavelengths are closer each other than the wavelength of WDM. In the DWDM technology, the wavelength range in between 1530 and 1560 nm are used and it is possible to transmit the number of 8,16,32,80 and 160 traffic channels in narrower channel between 10nm-01nm ranges.
Figure 2.13 160 λ has the capacity to example WDM transmission
2.3.CLASSIFICATION OF COMPUTER NETWORKS 2.3.1. LOCAL AREA NETWORK
Local Area Network (LAN) is a network that is created to connect the computers which are distributed up to 7 km area in a particular location. Initially LAN was consisted a small system that a server connected with a small number terminals via coaxial cable. But today, LAN has become highly productive network that supports higher speed demand and also it supports audio and video-conferencing as well as data transmitting. Home network, office network, and a university network could be given an example for local area network. It could be created as a large network that contains hundred computers, fax-modems, CD-ROM drivers, printers and other connected equipment as well as it could be a small network that consists two computers. One of the major advantages of the local area network is that allows users to use available resources such as hardware, software, printer, etc. which are connected in same LAN. And this sharing is providing to be achieved the saving source. [13]
2.3.2. METROPOLITAN AREA NETWORK
The network which structure consists connected computers around 5-100 km area is called Metropolitan Area Network (MAN). It could be applied in wider range than local area network. For example the network which is establishing between cities. MAN is a mod-scale network system. Audio and data communication can be performed in MAN. Its network scale is between WAN and LAN’s size. MAN connections usually perform the sharing of local resources on the network with high speeds. MAN protocols are defined by as IEEE, ITU-T standards protocols. ATM (Asynchronous Transfer Mode), DQDB(Distributed Queue Dual Bus), FDDI(Fiber Distributed Data Interface), Gigabit Ethernet, 10 Giga Ethernet, WiMAX and SMDS (Switched Multimegabit Data Service) can be listed as example of protocol and technology by using MAN connectivity.[1]
2.3.3. WIDE AREA NETWORK
Wide Area Network (WAN) is composed by connecting the computers with each other in an area which is larger than 100 km. This network is used with both MAN and LAN clusters.
WANs are a structure that is connecting together all local area networks in different locations of country. Internet which is used actively in todays is a good example for wide area network. It supports that the users of institutions who are located in different areas can transfer their data to other users, agencies etc. According to this feature this network design is more efficient to reduce cost and delays (i.e. time saving). The main feature of WAN connection is that it has long communication line and according to this feature to keep the transmission between long distances it is necessary to rent a telecomm operator. The bandwidth of communication is limited so a fee is paid based on using bandwidth. Thus, the important points for WAN connection are bandwidth, cost, connection quality and service quality.
2.4. ISO-OSI REFERANCE MODEL
Every computer manufacturer in the early years of the network was developing its own standards. Therefore, only the same manufacturer's devices could communicate with each other. This situation implies that who want to establish a network of institution needs to buy from a single device manufacturers. Due to the lack of inability to communicate with a different devices. Manufacturer from other institutions were needed to create an international standards. OSI (Open System Interconnection) model was developed by the ISO (International Organization for Standardization) in the late 1970s to put an end to this complication. With OSI model regardless of the type of the model, all equipments are able to communicate with each other. According to the OSI reference number: data communication is occurred in 7 layer. These are shown in Figure 2-14.[13]
Figure 2-14 OSI Reference Model
2.4.1 PHYSICAL LAYER
2.4.2 DATA LINK LAYER
This layer is responsible with control of the transportation and flow of data from one point to another. It forms the 2nd layer by attaching error control bits to data sets which are derived from link layer. In data layer, the transportation type of data in physical environment and addressing are described. By means of physical addressing is MAC (Media Access Control) addresses. This layer have the function of addressing, error identification, arbitration, and identification of the encapsulated data.
For addressing issue examples MAC, Unicast, Broadcast and Multicast addresses can be given. In data link layer, Frame Relay, ATM, HDLC protocols can be used. Furthermore, repeaters, switches, hubs and bridges are work in Layer 2 Datalink layer. [13]
2.4.3 NETWORK LAYER
Network layer is a layer which provides the movements of data sets between local or wide networks. It allows data packets to be routed through the network to reach its destination addresses. Addressing can be done by dynamic or static. The dynamic addressing is done by DHCP protocol with servers, the static addressing is done manually. In this layer, the best way to send data to the target can be done by router devices. Routing activities can be done by using routing protocols such as RIP, IGRP, OSFP and EIGRP.
2.4.4 TRANSPORT LAYER
The transport layer is the layer for two units which provides end to end connection and provides network service for these units. It provides a safety transportation of the data from the source to the target computer. The delivery situation of the data can be checked by appropriate protocols. It provides communication between OSI’s first three lower layer and upper layer. The most important role of this layer is Security and Flow Control. The aim of the flow control is to control the data in order to send to the correct address and to ensure that if the data is not delivered correctly, the flow control is responsible to send data again.
2.4.5 SESSION LAYER
2.4.6 PRESENTATION LAYER
It can be described as a high level communication interface between user programs and network. It is also used for the identification of a common format for the computer that data are planned to send. In another word, it describes the file extension’s identity. It resolves the problem of disconformity occurred from the usage of different protocols used by devices. For example: MPEG, GIF, TXT, ASCII, JPEG, AVI etc.
2.4.7 APPLICATION LAYER
It is the layer in which the network operating system, providing service to the users, and application programs exist. All the programs, used by the users, are declared in this layer. This layer presents some tools to the programs to use the network we can give everything we see in our monitor as an example. It’s the closest layer to the user, does not serve anything to the other layers. FTP, TFTP, HTTP, TELNET, SNMP, and SMTP protocols are applications used in this layer as an example. Reaching the internet, sharing the documents, emailing and database management and such operations are done in this layer. [13]
2.5 ROUTING PROTOCOL
Router devices using appropriate router protocols build a database. Database is built, by using IP address information, subnet mask, the data of neighboring routers. The alteration of this data are organized in RIB charts and all the needed calculations are done. Routing process is done by choosing the most appropriate path. Chosen or chosen to be used paths should have been introduced to the neighbor routers in the network. In this way, the router knows the ways going to the different routers too. The handshake between the routers is named routing update. If the routers are under the control of one management team, and all the describing, management rule detections are only done by this team, this means routing domain is constituted. Each different router orbit is used as a different autonomous system. [14]
Each router, according to the method, forms a RIB chart referring to the updates coming from the other router. By this chart, the best way to target is defined. Routing protocol, to use the ways and find the new ways, uses two main protocols named Dynamic Routing Protocol and Static Routing Protocol.
2.5.1. STATIC ROUTING PROTOCOL
In this protocol, network manager determines the route from the source to the target. There is no need for any protocol to calculate or transact. Routing protocols are calculated or determined by network administrator in advance. By adding, route data to data package which routers are going to be used are identified. During the static routing, next hop data is identified by network administrator. Thus, during transferring data to a different network the data is sent to the next router.
2.5.2. DYNAMIC ROUTING PROTOCOL
By large applications in network, more operations were being done via these networks. Static routing protocol was poor for large inclusive applications and for making the operations faster, comes the dynamic routing protocol. Dynamic routing protocol as a structure, uses routing protocol messages, thus given info to the leaders about networks gives way to periodic updates, and the best ways to these updates. By this means, routing charts are updated and the updated charts are transferred to other routers. In line with this process, the most appropriate way for the data from the source to the target is chosen.
For all these routing process to be done, all the routers in the network should use the same routing protocols. [15]
Figure 2.15 Dynamic Routing Protocol Examples
In dynamic routing protocol, for each packet the route can be determined according to separate calculations. To form the routing information, routing calculations are used. As it can be seen at the figure 2.15, using static routing protocol in a large and complicated network, can lead a lot of problems. In dynamic routing protocol structure, while sending data packages the most appropriate way can be chosen according to that very moment.
Since we are going to handle with EIGRP from distance vector protocols and OSPF, form link state protocols, below we are going to handle with all these protocols separately.
Figure 2.16 Dynamic Routing Protocol structure
2.5.2.1 OPEN SHORTEST PATH FIRST (OSPF)
OSPF is in the group of link-state routing protocols and is built on the structure of interior gateway protocol. In short, IGP does routing only in autonomous systems. It cannot be used between autonomous systems. Thus, the changing of the routing charts can be faster. In the link-state routing protocol, for choosing the best path Dijkstra Algorithm (the shortest path calculation algorithm) is used. Routers, because of the characteristics of Dijkstra Algorithm, has all the topological routing protocol data of the network which they depend on link-state. Thanks to the multicast characteristic feature sends the updates which are in their own routing charts to the routes which are indicated in advance.
In OSPF, routers running with line status protocols have information about all network and they can be aware of any changes that occur in the network. Thus, all subnets can be grouped under a tree and according to the Shortest Path First algorithm, the shortest path can be decided for the destination. In networks which use these protocols, information is just sent about the change when changes occur and with this way unnecessary protocol traffic is avoided.
By using OSPF, the information that is unavailable in network becomes known by all routers which applied the protocol and the packets that are transmitting to the unreachable network does not allow any data flow. Due to this optimization all disadvantages which are occurred by static routing are resolved. [4]
Depending on the situation, the network administrator can take into account the hop number for the shortest path or can create a more effective topology by considering factors such as delay in switching path, intensity of usage and bandwidth. Routers in OSPF can exchange information with each other. On the other hand, OSPF is not able to know how many steps needed for reaching a network but is able to know when and in which speed it can reach to the network. In addition to this, OSPF have four different network ranks: Backbone area, Stub area, Totally stubby area and Not-so-stubby area [4]
Likewise, router can be ranked as below: • ABR - Area Border Router
• ASBR – Autonomous System Boundary Router • IR – Internal Router
• BR – Backbone Router • DR – Designated Router
• BDR – Backup Designated Router [18]
2.5.2.2 EIGRP
Enhanced Interior Gateway Routing Protocol is a protocol developed by Cisco. EIGRP protocol can only be used in Cisco devices. It cannot be used in different router brands. EIGRP can be classified under Hybrid Routing protocols. This means that, in appropriate cases, Link-State can be active or Distance-Vector can be active.
Protocols such as RIP and IGRP are able to update topology updates and all network information as well as other new updates to routers. However, EIGRP protocol works totally in the opposite way and only share new topology differences with other routers.
2.6 VIRTUAL PRIVATE NETWORK (VPN)
Virtual Private Networks provide secure connection over communication networks by using encapsulation. Main purpose of the VPN is to establish secure virtual communication channels between two end points over leased connections from service providers. For virtual connection, end points should have both physical connections established between and also end point communication devices supporting VPN features. With this, from a single physical connection, many virtual VPN tunnels can be defined. These logically separated VPN connections provide independent communication channels between end points.[16]
2.7 MULTI PROTOCOL LABEL SWITCHING (MPLS)
Multi-Protocol Label Switching (MPLS) is getting stems from Toshiba’s cell switch routing, Ipsilon’s IP switching, IBM’s Aggregate Route-Based IP Switching, (ARIS) and Cisco’s Label Switching. MPLS technology has been started to be developed by an IETF task force in 1997. It adds label switching mechanism to existing IP backbone functionality. With this approach, normally datagram based IP networks obtain virtual leased line based data networks’ characteristics and qualities. [16]
Many companies worked for solution to have Layer 2 switching speed in Layer 3, to get rid of difficulties in controlling, managing the network and providing better scalability for IP over ATM applications, to have QoS support for multimedia applications and to have multi Layer 2 protocol support. These studies show a necessity to have some kind of common ground and integration between ATM based cell switching and IP routing based internet. MPLS solves many of the problems associated with somewhat synthetically establishing connection based circuits for IP protocol over ATM network.[2]
Due to rapid internet growth in recent years, internet technologies also face rapid changes. Increasing internet subscriber quantity encouraged worldwide access to internet infrastructure, better service quality, more bandwidth and allows for internet service versatility. For this reason, internet service providers and Telecommunication companies are forced to adopt their existing infrastructure for continuous technological advances and to cope up with increasing subscriber demand.
Telecommunication companies utilized IP over ATM approach in 1990s which was the best technology for this time period. MPLS technology employs label swapping for reaching target node instead of node to node IP routing (label swapping and forwarding). MPLS can be considered as an enhancement to existing IP infrastructure. New applications include traffic engineering, IP VPN, integration with IP routing and Layer 2 or optical switching. This provides for high performance IP backbone architecture. [2]
advantage of both IP routers’ routing protocol support and ATM switches’ cell header (label) switching. Basic structure is shown in Figure 2.17.
Figure 2.17 Formation of MPLS
MPLS has short, fixed length labels that identify IP packet headers which allow for easier packet forwarding. IP packets are wrapped inside additional MPLS headers and then forwarded. This makes forwarding easier as it avoids hop by hop routing and uses label switching instead. MPLS frames can be transported over any Layer 2 infrastructure like ATM, Frame Relay, PPP or Ethernet etc. In frame based MPLS labels are inserted between Layer 2 and Layer 3 headers. This labelling process is called inserting Shim Header. MPLS enables forwarding of IP packets through a predefined label path over the network. This predefined path is called as Label Switched Path (LSP). LSPs are uni directional and similar to ATM PVC (Private Virtual Circuit). Label Switch Router (LSR) defines the path where packet will be forwarded and each LSR which this LSP traverses makes forwarding decision according to these labels and forwards this MPLS frame to next LSR node.
2.7.1 MPLS ARCHITECTURE AND BASIC COMPONENTS
Main components of MPLS architecture are as follows; MPLS Label, Label Switching, Label Switched Path (LSP), Label Switching Router (LSR) and Forwarding Equivalence Class (FEC). MPLS network is composed of LSRs that are located in the center of the network and surrounding Edge-LSRs (Label Edge Router – LER).
2.7.1.1 MPLS LABEL
Figure 2-18 MPLS Label Format
MPLS header which is located between Layer 2 header and IP header is composed of 4 octets (32 bits). 3 bits inside this header is used for Class of Service (CoS). This service class information is for traffic precedence for special applications and defines QoS levels in the MPLS network. 8 bits TTL value is used for mimicking IP TTL which is inside the IP header. Each IP packet has a Time to Live (TTL) value that prevents packets from entering into an infinite forwarding loop. TTL field value reduced by one for each forwarding action and when it reaches to zero, this packet is discarded. There is also a 1 bit field which shows the stacking status and indicates whether encapsulated label is the last one in the stack or not. Remaining 20 bits of the header has the real MPLS label value.[2]
2.7.1.2 LABEL CHANGES
Label switching logic should be provided to the nodes before MPLS packets arrive to the nodes, this is realized by signaling and label distribution. Each packet should be classified in the edge of the MPLS network in order to associate them with an MPLS label, this is performed by Label Edge Router (LER). LER searches its routing table for a match, adds corresponding label to this packet as ingress router that is in charge of this classification, and sends the MPLS frame to next LSR via defined Label Switches Path (LSR).
Arguably the most prominent benefit of label switching is the ability to associate any user traffic type with a Forwarding Equivalence Class (FEC) and then forwarding this classified traffic through a LSP path. This functionality helps ISPs to make an exact and deterministic flow control over their networks, better and controllable utilization of the network resources and more predictable overall network behavior.[2]
2.7.1.3 LABEL SWITCHING ROUTER (LSR)
LSR is the high speed switching and routing device in a MPLS network which participates in formation of Label Switched Paths (LSP). It fulfills the functions of forwarding packets from source to destination and populating the routing-label table. LSRs are placed in the core of the network and makes label switching according to available forwarding table information. They can be routers or switches. They combine the Layer 2 performance and traffic management qualities with Layer 3 routing support and flexibility. Figure 2-19 shows LSR function.
Figure 2-19 Formation of LSR
2.7.1.4 LABEL SWITCHED PATHS (LSPs)
Within MPLS network before any data communication starts, LSPs are formed between two endpoints where packet transport intended to take place. LSP labels are distributed via signaling and FEC associations are realized. All traffic has to go through LSPs in MPLS. LSPs are formed by two methods, Explicit Route or Node by Node routing. [18]
2.7.1.4.1 HOP BY HOP ROUTING
2.7.1.4.2 EXPLICIT ROUTING
Explicit routing is based on having defined LSR address list in the sender node explicitly, which includes all the intermediate nodes that interconnect sender node to the receiver node. This list is arranged in a way to have the ip addresses of the equipments that participate in this LSP. Explicit routing is realized with two methods, strict and loose explicit routing. In strict method, only LSRs defined by sending LER is used. Additionally it is required to follow the sequence defined in LER. In loose routing mode, it is allowed to use additional LSRs other than the defined ones when it becomes necessary. Each LSR cannot select next hop independently. In the first sending LSR, the node list is defined. By this way resources in the network can be reserved for data transport with sufficient QoS guarantees.
2.7.1.5 FORWARDING EQUIVALENCE CLASSES (FEC)
FEC represents the group of packets which will receive the same treatment while being transported. Can be defined as a packet group which has the same source and destination address. For the packets that are grouped in this way, routing to destination node is performed in the same manner. Grouping of the packets which are destined for the same end point allows to assign them a single label and allows a common routing for them. Thus, according to traffic type different prioritization and service qualities can be provided. For each LSP a FEC definition is done. Each FEC defines one or more FEC element group and each FEC element defines the group of packets that correspond to LSP.
2.7.2. LABEL DISTRBUTION PROTOCOL (LDP)
LDP is the protocol which is responsible for the distribution of labels. It is set of procedures that an LSR informs the other LSRs about its label/FEC assignments. LSR routers that communicates their label/FEC assignments to each other are called “label distribution pairs”. These LSR routers have “label distribution neighborhood”. The important point is that while two LSR routers can be label distribution pairs for some label/FEC assignments, they may not be label distribution pairs for other label/FEC assignments. Additionally LDP protocol includes the procedures for label distribution pairs to learn MPLS capabilities of each other.
MPLS architecture does not oblige to use single type of label distribution protocol (LDP). RSVP and BGP protocols are extended in a way to make it possible to exchange labels and make label distribution.
Each FEC is assigned with short, fixed length and locally significant identifiers/labels. This label is either located inside the data link layer header or network layer header. In case there is no available field for label value to be inserted, a special header is inserted into the packet.
3 PROCESS AND RESULTS
This part of the thesis is realized in two sections. First section is devoted to microwave radio link design in order to provide communication between two locations and based on modelling of different radio link solutions with different modulation techniques, different antenna dimensions etc. by using PathLoss program software. Results are evaluated against annual transmission loss rate and optimal radio link solution is decided. Second section focusses on L2 Ethernet VPN over MPLS lab simulation by using GNS3 program software for point to point and point to multipoint MPLS applications.
3.1. RADIO LINK DESIGN BY USING PATHLOSS PROGRAM
PathLoss program software requires exact geographical coordinates of two radio link end points and by using SRTM (Shuttle Radar Topography Mission) Digital Elevation Model information of the Earth ( high-resolution digital topographic database of Earth), calculates LoS (Line of Sight) status and link budget by taking into account free space loss, rain loss, refraction, diffraction, reflection,aperture-medium coupling loss, and absorption.
Path loss (or path attenuation) as a definition is the reduction in power density (attenuation) of an electromagnetic wave as it propagates through space. Path loss is a major component in the analysis and design of the link budget of a telecommunication system. Other than free space loss and rain loss etc., path loss / attenuation is also influenced by terrain contours, environment (urban or rural, vegetation and foliage), propagation medium (dry or moist air), the distance between the transmitter and the receiver, and the height and location of antennas.
Path loss normally includes propagation losses caused by the natural expansion of the radio wave front in free space (which usually takes the shape of an ever-increasing sphere), absorption losses (sometimes called penetration losses), when the signal passes through media not transparent to electromagnetic waves, diffraction losses when part of the radio wave front is obstructed by an opaque obstacle, and losses caused by other phenomena.
In the study of wireless communications, path loss can be represented by the path loss exponent, whose value is normally in the range of 2 to 4 (where 2 is for propagation in free space, 4 is for relatively lossy environments and for the case of full specular reflection from the earth surface—the so-called Flat Earth model). In some environments, such as buildings, stadiums and other indoor environments, the path loss exponent can reach values in the range of 4 to 6. On the other hand, a tunnel may act as a waveguide, resulting in a path loss exponent less than 2.
Path loss is usually expressed in dB. In its simplest form, the path loss can be calculated using the formula [20]
Where L is the path loss in decibels, n is the path loss exponent, d is the distance between the transmitter and the receiver, usually measured in meters, and C is a constant which accounts for system losses.
Radio and antenna engineers use the following simplified formula (also known as the Friis transmission equation) for the path loss between two isotropic antennas in free space:
Path loss in dB: [20]
Where L is the path loss in decibels, lambda is the wavelength and d is the transmitter-receiver distance in the same units as the wavelength.
3.1.1. PATH LOSS RADIO LINK DEFINITIONS FOR SAMPLE LINK
Figure 3-1 Link Definitions in Path Loss
Figure 3-2 Generating Path Profile and terrain data for Site 1
Figure 3-3 Generating Path Profile and terrain data for Site 2
Figure 3-4 Clutter Backdrop and terrain data
PathLoss tool has another screen (Figure 3-5) for analyzing exact LoS status where the height profile between Site 1 and Site 2 can be graphically and tabular seen.
Figure 3-5 Terrain data
Figure 3-6 Antenna Heights
Next sections use this antenna height assumption and by changing modulation and antenna types, the overall radio link availability values with different transmission capacities are evaluated for five different radio link designs.
3.1.1.1 DESIGN SIMULATION -1
Various design simulations are studied for achieving the highest radio link capacity while still satisfying the high transmission availability values. All radio link models are based on a commercial microwave equipment manufacturer’s (DragonWave Inc.) Harmony Radio product family which has a wide range of microwave radios that start from 3.5Ghz to 42Ghz and variable spectrum which can be adjusted between 3.5 to 56Mhz channel bandwidth.
For all radio link calculations, PathLoss IP radio model of 8Ghz Dragonwave Harmony Radio is used and antenna is selected from Andrew Corporation (VHLP series, frequency range 7125 Mhz – 8500Mhz) with various diameters but with single polarization in order to be able to decide on optimal design.
For the Simulation -1, Harmony Radio with 256QAM modulation and 56 MHz channel bandwidth is considered together with 1.8m antenna. Harmony Radio can provide a transmit power of TX = 17 dBm for this mode, and antenna gain is 40.8 dBm for 1.8m antenna. This results in an EIRP (Equivalent Isotropically Radiated Power) value of 57.8 dBm for both end points in Site 1 and Site 2. If we consider additional antenna gain of 40.8dBm on the receiving site as well, total gain budget of 98,6 dBm becomes available both for Site 1 and Site 2. At this modulation level Harmony Radio has a receiver sensitivity of 65dBm so, if we consider the free space loss of 138,33dBm (for a distance of 24,54km) and Atmospheric absorption loss of 0,26dBm and Field margin of 1dBm, we end up with receive signal of -40.99dBm (which is safely in line with -65dBm receiver sensitivity). This allows for quite sufficient thermal fade margin of 24dB, which in turn provides a good overall transmission link availability (Annual rain + multipath availability : %99,99990).
Figure 3-7 and Figure 3-8 show consecutively the transmission analysis screen with calculated attenuation values, selected antenna model and radio model with gain values and the antenna pattern for 1.8m 8 GHz single polarized antenna. Figure A-1 provides detailed information for Radio and Antenna model used in this simulation and related threshold and gain values to achieve a BER ratio of 10-6.
Figure A-2 shows the rain loss related PathLoss tool values for the selected geographical area, ITU-T Region K is automatically selected by using ITU algorithm Rec. ITU-R P.530-8/13 for 8 GHz frequency. Used rain rate data source is ITU-R P.837-5 database.
Figure 3-7 Transmission Analysis 1
Figure 3-8 Transmission Analysis for Antenna 1.8m
Figure A-4 shows the Radio Specification for 256QAM modulation level, PathLoss program uses the specified values of TX_POWER and RX_THRESHOLD values specific for this microwave radio.
Site 1 Site 2 True azimuth (°) 32.58 212.68 Vertical angle (°) -0.46 0.29 Elevation (m) 1178.30 1026.99 Tower height (m) 30.00 30.00 Antenna model VHLP6-7W (TR) VHLP6-7W (TR) Antenna file name vhlp6-7w vhlp6-7w Antenna gain (dBi) 40.80 40.80 Antenna height (m) 22.93 14.22
Frequency (MHz) 8000.00 Polarization Vertical Path length (km) 24.54 Free space loss (dB) 138.33 Atmospheric absorption loss (dB) 0.26
Field margin (dB) 1.00
Net path loss (dB) 57.99 57.99 Radio model 08HR56HET348v01 08HR56HET348v01 Radio file name 08hr56het348v01 08hr56het348v01 TX power (dBm) 17.00 17.00 Emission designator 56M0D7WET 56M0D7WET
EIRP (dBm) 57.80 57.80
RX threshold criteria 1E-6 BER 1E-6 BER RX threshold level (dBm) -65.00 -65.00
Receive signal (dBm) -40.99 -40.99 Thermal fade margin (dB) 24.01 24.01 Dispersive fade margin (dB) 37.27 37.27 Dispersive fade occurrence factor 1.00
Effective fade margin (dB) 23.81 23.81 Geoclimatic factor 1.768E-006
Path inclination (mr) 6.52 Fade occurrence factor (Po) 6.731E-004
Worst month multipath availability (%) 99.99972 99.99972 Worst month multipath unavailability (sec) 7.35 7.35 Annual multipath availability (%) 99.99995 99.99995 Annual multipath unavailability (sec) 16.04 16.04 Annual 2 way multipath availability (%) 99.99990
Annual 2 way multipath unavailability (sec) 32.08 Polarization Vertical 0.01% rain rate (mm/hr) 26.71 Flat fade margin - rain (dB) 24.01 Rain attenuation (dB) 24.01 Annual rain availability (%) 100.00000 Annual rain unavailability (min) 0.01 Annual rain + multipath availability (%) 99.99990 Annual rain + multipath unavailability (min) 0.54
Site 1 to Site 2 radio link design with the specified modulation and antenna type results in an overall link availability value of %99,99990 (including annual rain and multipath related effects) which means 0,54 minutes of interruption of traffic for one year. With 56 MHz spectrum bandwidth and 256QAM modulation level, a high traffic capacity of 348Mbps is achievable between Site 1 and Site 2 with very limited interruption annually.
3.1.1.2 DESIGN SIMULATION -2
For the Simulation -2, Harmony Radio with 256QAM modulation and 56 MHz channel bandwidth is considered together with 1.2m antenna. Harmony Radio can provide a transmit power of TX = 17 dBm for this mode, and antenna gain is 37.3 dBm for 1.2m antenna. This results in an EIRP (Equivalent Isotropically Radiated Power) value of 54.3 dBm for both end points in Site 1 and Site 2. If we consider additional antenna gain of 37.3dBm on the receiving site as well, total gain budget of 138,33 dBm becomes available both for Site 1 and Site 2. At this modulation level Harmony Radio has a receiver sensitivity of 65dBm so, if we consider the free space loss of 138,33dBm (for a distance of 24,54km) and Atmospheric absorption loss of 0,26dBm and Field margin of 1dBm, we end up with receive signal of -47.99dBm (which is safely in line with -65dBm receiver sensitivity). This allows for quite sufficient thermal fade margin of 17dB, which in turn provides a good overall transmission link availability (Annual rain + multipath availability : %99,99947).
Figure 3-9 Transmission Analysis 2, Pathloss Calculation with 1.2m Antenna
Figure 3-10 Transmission Analysis 2 for Antenna 1.2m
Site 1 Site 2 True azimuth (°) 32.58 212.68 Vertical angle (°) -0.46 0.29 Elevation (m) 1178.30 1026.99 Tower height (m) 30.00 30.00 Antenna model VHLPX4-7W (TR) VHLPX4-7W (TR) Antenna file name vhlpx4-7w vhlpx4-7w Antenna gain (dBi) 37.30 37.30 Antenna height (m) 22.93 14.22
Frequency (MHz) 8000.00 Polarization Vertical Path length (km) 24.54 Free space loss (dB) 138.33 Atmospheric absorption loss (dB) 0.26
Field margin (dB) 1.00
Net path loss (dB) 64.99 64.99 Radio model 08HR56HET348v01 08HR56HET348v01 Radio file name 08hr56het348v01 08hr56het348v01 TX power (dBm) 17.00 17.00 Emission designator 56M0D7WET 56M0D7WET
EIRP (dBm) 54.30 54.30
RX threshold criteria 1E-6 BER 1E-6 BER RX threshold level (dBm) -65.00 -65.00
Receive signal (dBm) -47.99 -47.99 Thermal fade margin (dB) 17.01 17.01 Dispersive fade margin (dB) 37.27 37.27 Dispersive fade occurrence factor 1.00
Effective fade margin (dB) 16.97 16.97 Geoclimatic factor 1.768E-006
Path inclination (mr) 6.52 Fade occurrence factor (Po) 6.731E-004
Worst month multipath availability (%) 99.99865 99.99865 Worst month multipath unavailability (sec) 35.52 35.52 Annual multipath availability (%) 99.99975 99.99975 Annual multipath unavailability (sec) 77.48 77.48 Annual 2 way multipath availability (%) 99.99951
Annual 2 way multipath unavailability (sec) 154.95 Polarization Vertical 0.01% rain rate (mm/hr) 26.71 Flat fade margin - rain (dB) 17.01 Rain attenuation (dB) 17.01 Annual rain availability (%) 99.99996 Annual rain unavailability (min) 0.22 Annual rain + multipath availability (%) 99.99947 Annual rain + multipath unavailability (min) 2.80
Site 1 to Site 2 radio link design with the specified modulation and antenna type results in an overall link availability value of %99,99947 (including annual rain and multipath related effects) which means 2,40 minutes of interruption of traffic for one year. With 56 MHz spectrum bandwidth and 256QAM modulation level, a high traffic capacity of 348Mbps is achievable between Site 1 and Site 2 with very limited interruption annually.
3.1.1.3 DESIGN SIMULATION -3
For the Simulation -3, Harmony Radio with 64QAM modulation and 56 MHz channel bandwidth is considered together with 0.6m antenna. Harmony Radio can provide a transmit power of TX = 19 dBm for this mode, and antenna gain is 30.6 dBm for 0.6m antenna. This results in an EIRP (Equivalent Isotropically Radiated Power) value of 49.6 dBm for both end points in Site 1 and Site 2. If we consider additional antenna gain of 30.6dBm on the receiving site as well, total gain budget of 138,33 dBm becomes available both for Site 1 and Site 2. At this modulation level Harmony Radio has a receiver sensitivity of 65dBm so, if we consider the free space loss of 138,33dBm (for a distance of 24,54km) and Atmospheric absorption loss of 0,26dBm and Field margin of 1dBm, we end up with receive signal of -59.39 (which is safely in line with -65dBm receiver sensitivity). This allows for quite sufficient thermal fade margin of 11.61dB, which in turn provides a good overall transmission link availability (Annual rain + multipath availability : %99,99804).
Figure 3-11 Transmission Analysis 3, Pathloss Calculation with 0.6m Antenna and 64 QAM modulation
Figure 3-12 Transmission Analysis 3 for Antenna 0.6m a 64 QAM modulation
