pathloss 5.0

Selasa, 24 November 2009 di 00.00 | 0 komentar

GLOBAL SYSTEM FOR MOBILE COMMUNICATIONS (GSM)

In 1982, the Nordic PTT sent a proposal to Conférence Européenne des Postes et Télécommunications (CEPT) to specify a common European telecommunication service at 900 MHz. A Global System for Mobile Communications (GSM) standardization group was established to formulate the specifications for this pan-European mobile cellular radio system. During 1982 through 1985, discussions centered around whether to build an analog or a digital system. Then in 1985, GSM decided to develop a digital system. In 1986, companies participated in a field test in Paris to determine whether a narrowband or broadband solution would be employed. By May 1987, the narrowband Time Division Multiple Access (TDMA) solution was chosen. Concurrently, operators in 13 countries (two operators in the United Kingdom) signed the Memorandum of Understanding (MoU) which committed them to fulfilling GSM specifications and delivering a GSM system by July 1, 1991. This opened a large new market. The next step in the GSM evolution was the specification of Personal Communication Network (PCN) for the 1800 MHz frequency range. This was named the Digital Cellular System (DCS) 1800. The Personal Communication Services (PCS) 1900 for the 1900 MHz frequency range was also established.

THE DIFFERENT GSM-BASED NETWORKS

Different frequency bands are used for GSM 900/1800 and GSM 1900 (Figure 1). In some countries, an operator applies for the available frequencies. In other countries (e.g. United States), an operator purchases available frequency bands at auctions.

Figure 1 Frequency Band for different GSM

NETWORK HARDWARE

Every cellular system has hardware that is specific to it and each piece of hardware has a specific function. The Ericsson GSMbased systems comply to the GSM standard while varying from

it for the purpose of overall system improvement. The system solutions integrate existing hardware and new technology to provide a “total” solution to the mobile telephony market. The major systems in the network are:

· Operation and Support System

· Switching System

· Base Station System

The system is normally configured as depicted in Figure 2.

Figure 2 GSM Based System Model

OPERATION AND SUPPORT SYSTEM (OSS)

For GSM system administration, the OSS supports the network operator by providing:

· Cellular network administration

· Network operation and support

SWITCHING SYSTEM (SS)

Figure 3 shows the main components of the switching system. The following is a brief description of each of these components.

Figure 3 Switching System

· Mobile Services Switching Center (MSC)

The MSC is responsible for set-up, routing, and supervision of calls to and from mobile subscribers. Other functions are also implemented in the MSC, such as authentication. The MSC is built on an AXE-10 platform.

· Visitor Location Register (VLR)

In the GSM based solution, the VLR is integrated with the MSC. This is referred to as the MSC/VLR. The VLR contains non-permanent information about the mobile subscribers visiting the MSC/VLR service area, e.g. which location area the MS is in currently.

· Gateway MSC (GMSC)

The GMSC supports the function for routing incoming calls to the MSC where the mobile subscriber is currently registered. It is normally integrated in the same nodes as MSC/VLR.

· Home Location Register (HLR)

In GSM, each operator has a database containing information about all subscribers belonging to the specific Public Land Mobile Network (PLMN). This database can be implemented in one or more HLRs. Two examples of information stored in the database are the location (MSC/VLR service area) of the subscribers and services requested. The HLR is built on an AXE-10 platform.

· Authentication Center (AUC)

For security reasons, speech, data, and signaling are ciphered, and the subscription is authenticated at access. The AUC provides authentication and encryption parameters required for subscriber verification and to ensure call confidentiality.

· Equipment Identity Register (EIR)

In GSM there is a distinction between subscription and mobile equipment. As mentioned above, the AUC checks the subscription at access. The EIR checks the mobile equipment to prevent a stolen or non-type-approved MS from being used.

· Interworking Location Register (ILR)

Around the world there are market demands for roaming capabilities with GSM. The ILR is the node that forwards roaming information between cellular networks using different operating standards. This currently exists only in the GSM 1900 network.

· Short Message Service Gateway MSC (SMS-GMSC)

A Short Message Service Gateway MSC (SMS-GMSC) is capable of receiving a short message from a Service Center (SC), interrogating an HLR for routing information and message waiting data, and delivering the short message to the MSC of the recipient MS. In GSM system, the SMS-GMSC functionality is normally integrated in the MSC/VLR node.

· Short Message Service Interworking MSC (SMSIWMSC)

A Short Message Service InterWorking MSC (SMSIWMSC) is capable of receiving a mobile originated short message from the MSC or an ALERT message from the HLR and submitting the message to the recipient Service Center (SC). The SMS-IWMSC functionality is normally

integrated in the MSC/VLR node.

· Data Transmission Interface (DTI)

DTI - consisting of both hardware and software - provides an interface to various networks for data communication. Through DTI, users can alternate between speech and data during the same call. Its main functions include a modem and fax adapter pool and the ability to perform rate adaptation. It was earlier implemented as the GSM InterWorking Unit (GIWU).

BASE STATION SYSTEM (BSS)

The Base Station System (BSS) is comprised of two major components. They are:

· Base Station Controller (BSC)

· Base Transceiver Station (BTS)

Figure 4 Base Station System

The Base Station Controller (BSC) is the central point of the BSS. The BSC can manage the entire radio network and performs the following functions:

· Handling of the mobile station connection and handover

· Radio network management

· Transcoding and rate adaptation

· Traffic concentration

· Transmission management of the BTSs

· Remote control of the BTSs

Diposting oleh Pathloss50 Label: Refference

Draw Smith Chart Using excell

Jumat, 20 November 2009 di 16.18 | 0 komentar

A situation arose at work where we needed to be able to plot complex impedance points taken off the network analyzer display and plot them on a Smith Chart. A modification to the original Smith Chart for Excel permits doing so. If you download the new edition, you will need to enable the Analysis ToolPak (included with Excel as an Add-In) to perform the complex math.

The original Smith Chart for Excel that takes s-parameters as input is detailed below.

This example Excel workbook demonstrates how easy it is to implement a Smith Chart using only a standard x-y scatter chart and coordinate conversions. The workbook shown below used data imported from a typical S-parameter file (in this case an RF2321 amplifier, from RF Micro Devices) and plotted on a chart that uses an image file that contains a Smith Chart. Version 2.0 adds equivalent denormalized impedance with equivalent resistance and capacitance/inductance values. Version 2.1 corrects a graphical equation, but does not affect the accuracy of the previous versions (thanks to Peter for alerting me).

Step-by-step instructions are presented below. Click here to download the example workbook. Click here to download just the background Smith Chart graphic. Finally, click here if you would like a fully-detailed Smith Chart, created in Visio, with impedance and admittance lines.

If you appreciate the effort it took to develop this workbook, please consider making a donation to RF Cafe by clicking here (at the bottom of the list).

Engineers use spreadsheets for a myriad of applications from calculating cascaded chains of components to PLL phase noise prediction, but I can never recall seeing S‑parameters plotted in a spreadsheet using a Smith Chart¹. If a Smith Chart is included in a spreadsheet, it is usually an image pasted in from some other application. This article describes an extremely simple method of implementing a Smith Chart using the built‑in graphing capability of any modern spreadsheet program (Excel is used in this example). All that is required is an accurate graphic of a Smith Chart for use as the chart background image, and a rectangular‑to‑cylindrical coordinate conversion.

Smith Chart for Excel sample screen shot

Example Spreadsheet

Sample Smith Charts for S-parameters

RF2321 Datasheet Excerpt

Although the example given here is used to plot S‑parameters from a file, the possibilities are great for generating any sort of Smith Chart application such as for impedance matching.

A general-purpose amplifier (RF2321) manufactured by RF Micro Devices is used in this example, and its S-parameter file was downloaded from the RFMD website. A copy of the datasheet Smith Charts are given for results comparison. Here are step-by-step instructions for generating your first Smith Chart. Experienced Excel users might want to skip down to the image loading and calibration section.

Open a new workbook in Excel.
Click the "File/Open..." menu selection and locate the S‑parameter file to be plotted (in this case, “23212725.s2p”). Set the window to display "All Files (*.*)," since the S‑parameter file will most likely not end in an Excel extension.
The Text Import Wizard will open. Select the "Delimited" option, then click "Next."
Unclick the "Tab" checkbox and select "Space." Scroll down into the data area and verify that the data is separated by vertical lines at the appropriate points (lined up in columns), then click "Next."
Click "Finish." You will now have all the data imported into a worksheet. Now would be a good time to save the workbook under a new name (be sure to save it as an Excel worksheet).
The data column labels might need to be shifted to line up with the data (results will not be affected if left as is). The data cannot be plotted as imported and must be translated into equivalent circular coordinates (very simple).
Click the "Insert/Worksheet" menu selections.
Refer to the example spreadsheet as a suggested format for the plotting data.
In the "Freq (MHz)" column, use the equation ="Freq"/1e6, where "Freq" is referenced from the S‑parameter import worksheet. This column is not plotted, but is provided as a reference for the S‑parameter.
In the "S11x" column, use the equation ="|S11|"*cos("∕ S11"*PI()/180), where "|S11|" is the magnitude and "
In the "S11y" column, use the equation ="|S11|"*sin("∕ S11"*PI()/180).
In the "S22x" column, use the equation ="|S22|"*cos("∕ S22"*PI()/180).
In the "S22y" column, use the equation ="|S22|"*sin("∕ S22"*PI()/180).
That creates the first row of equations. Now, highlight all five cells and grab the "handle at the lower right corner of the highlighted area and drag it down by the number of rows of imported data (201 in this case). You can cut out whatever data you do not want to plot.
Use the "Format/Cells..." menu selection to format the numbers to your preference.
Highlight the entire group of S‑parameter data (201rows by 4 columns), then click the "Insert/Chart..." menu selection. Click the "XY (Scatter)" chart type and then select the "Scatter with data points connected by lines." picture in the lower left. Do not worry that the preview looks meaningless at this point. Click "Next."
Select the "Series" tab. Highlight "Series 1" in the list, then place the cursor in the "Name" edit box and type in S11. The name in the list will change to "S11."
Click "Series 2" in the list and then click the "Remove" button.
Click "Series 3" in the list and rename it to S22. In the "X Values" edit box, change the "$B" to "$D" on both sides of the colon, then click "Next."
Click the "Gridlines" tab and uncheck everything, then click the "Legend" tab and select the "Corner" option. Click "Next," then "Finish."
Move the chart to a convenient place on the worksheet, and reshape it to as close to a square as possible. Not being a perfect square will not affect the accuracy of the plotted points, but will make a nasty looking Smith Chart.
Click an open area of the graph (the "Plot Area") and use the "handles" to resize the graph to fill the graph window (it will not go all the way to the edge).
LOADING THE SMITH CHART IMAGE
Right-click in the Plot Area and select the "Format Plot Area..." menu selection, then click the "Fill Effects..." button. Next, click the "Picture" tab and click the "Select Picture..." button.
Navigate to where your favorite Smith Chart image is located and select it. The one used in this example can be downloaded from the RF Cafe web site. If you are creating your own version, the best results can be had using a vector image creator (such as Visio) and then saving it in WMF or EMF format. Doing so preserves the sharpness of lines when resizing. It is also necessary to provide white space around the edge of the image to allow for the Excel plot area not being able to extend all the way to the edges. Click Insert. Click the "OK" buttons to close all the formatting windows.
CALIBRATING THE SCALES
Somewhere on the worksheet enter the numbers -1, 0, and 1 in separate cells. These will be used to set the scale to correspond with the outer circle.
Right-click in the Plot Area and choose the "Source Data..." menu selection, then click the "Series" tab.
Click the "Add" button and type "-1+j0" in the "Name" edit area. Place the cursor in the "X Values" edit area and select the cell with the "-1" in it. Place the cursor in the "Y Values" edit area and select the cell with the "0" in it. Note that any default values in the edited areas must be overwritten.
Click the "Add" button and type "1+j0" in the "Name" edit area. Place the cursor in the "X Values" edit area and select the cell with the "1" in it. Place the cursor in the "Y Values" edit area and select the cell with the "0" in it.
Click the "Add" button and type "0+j1" in the "Name" edit area. Place the cursor in the "X Values" edit area and select the cell with the "0" in it. Place the cursor in the "Y Values" edit area and select the cell with the "1" in it.
Click the "Add" button and type "0-j1" in the "Name" edit area. Place the cursor in the "X Values" edit area and select the cell with the "-1" in it. Place the cursor in the "Y Values" edit area and select the cell with the "0" in it. Click "OK."
Right-click the y-axis and select the "Format Axis..." menu selection, then click the "Scale" tab.
Set the "Minimum" value to -1.02, the "Maximum" value to 1.02, and the "Major unit" and "Minor unit" values to 5. Click OK."
Right-click the x-axis and select the "Format Axis..." menu selection, then click the "Scale" tab.
Set the "Minimum" value to -1.02, the "Maximum" value to 1.02, and the "Major unit" and "Minor unit" values to 5. Click "OK."
If the calibration marks do not line up with the unit circle of your Smith Chart, go back and adjust the scales until they do. After calibration, the marks and axis lines and labels can be removed to eliminate clutter.

That's all there is to it. As you can see, the results are identical to the published Smith Chart in the RFMD datasheet. Once you do the first one, the rest will be really easy. Of course, if you do not want to go to the trouble of carrying out the above procedure, you can simply go to the RF Cafe web site (http://www.rfcafe.com) and download the "Smith Chart for Excel" file free of charge. This exact example workbook is what you will be getting. - Enjoy!

REFERENCES

Smith Chart is a registered trademark of Analog Instruments Company, New Providence, NJ
“Field and Wave Electromagnetics,” by David K. Cheng, Addison Wesley, 1983

Please remember to credit RF Cafe for the idea if you use it in a publication!

Source : http://www.rfcafe.com/business/software/smith-chart-for-excel/smith-chart-for-excel.htm

Diposting oleh Pathloss50 Label: Refference, Telco Tools

Link Planning Tools (excell worksheet)

di 16.10 | 0 komentar

R. Alok K. Tiwari, of Idea Cellular Ltd., has graciously made this "Transmission Link Planning" workbook available. The following text is provided by Mr. Tiwari:

Click to download:

Important: If the file name is changed from the supplied "Link Planning Tool.xls," some of the macros will not function properly. It would be best to save the completed workbook under a new name, then start on new systems with the original file.

Here is the description for using the utility:
1. We mainly enter the parameter value into the
sheet "Calculations".
a. Entries shown in YELLOW cells are
mandatory.
b. Entries shown in GREY cells are to play with in order to
get the desired result wrt Standard Link Design Criteria.
c. Entries shown in SEA GREEN are ONE-TIME entries like
temperature, pressure etc.

DISCLAIMER: Use of this UTILITY is not intended for any commercial set-up. The author is not responsible for any type of damage occurred due to implementation of the results obtained from this utility to any commercial set-up.

Link Planner v7 Calculations Worksheet, by Mr. Alok K. Tiwari

Link Planner v7 Calculations Worksheet, by Mr. Alok K. Tiwari

PASSWORDS:
Sheet "Calculations" : Password "link"
Sheet "Antenna Heights": Password "antennae"
Sheet "Report": Password "report"
Sheet "DB_Ant1(18Ghz)": Password "antennae"
Sheet "DB_Ant2(15Ghz)": Password "antennae"
Sheet "DB_RadioEqpt": Password "radio"
Sheet "PassiveRepeater": Password "passive"

Above Passwords are activated into the file attached to this mail.
Please be careful while making any change to Sheet "Calculations" for it contains the most important formulae.

The "Calculation" sheet looks up for the required data :
a. For Antennae (of 18 GHz band) from the sheet:
"DB_Ant1 (18GHz).
Using the Password sizes and gains can be
modified.
Note that only FOUR sizes are permissible to
provide into this sheet.

b. For Antennae (of 15 GHz band) and Frequency of
Operation from the sheet:"DB_Ant2 (15GHz).
Using Password sizes and gains can be modified.
Note that only FOUR antennae sizes EIGHT Frequencies in TWO separate bands
can be used.
Also do not change the frequency named F1,F2,....F6,G1,G2. Only their respective
values can be changed.

c. For Radio Specific Data form the sheet:
DB_RadioEqpt.
Using Password we can also modify the Radio Names, their signature data and
Radio Parameters. Here THREE different type of Radios can be used.

Link Planner v7 Antenna Heights Worksheet, by Mr. Alok K. Tiwari

Link Planner v7 Antenna Heights Worksheet, by Mr. Alok K. Tiwari

2. The Sheet "Antenna Heights" is to calculate the antennae heights
based on LOS survey feedback data.

3. The Sheet "Report" is just the
compilation of information used in
link implementation.

This is to bring to your kind notice that formulae used into this workbook are as per ITU-T.As I'm using the Tool like Nokia's NETACT PLANNER and CTE's PATHLOSS, I've observed the similar results at least for Link Design parameters.

Source : http://www.rfcafe.com/business/software/link-planning-tool/link-planning-tool-excel.htm