CDMA_Ana

WIRELESS NETWORKSNORTHERN TELECOM CDMA RF DESIGN

CDMA Analysis V0.02 1 06/10/96

I. Overview of CDMA Parameters and their Variation Impacton System Design

Introduction:This section provides a brief discussion of the parameters used in designing a standardCDMA system. It also specifies the impact of variation of some parameters on the linkbudget. The design parameters used for designing SPRINT SPECTRUM CDMAcellular system are included. Any further changes or updates will be provided whenapplicable.

Frequency BandThe frequency of operation is in the 1900 MHz band. Both cellular systems A and Bhave been assigned a total bandwidth of 30 MHz (15 MHz in each direction). With1.25 MHz CDMA channel bandwidth, the maximum number of carriers in each down(forward) and up (reverse) links is 11. The Base Station for system A transmits in thefrequency range 1930-1945 MHz and receives in the range 1850-1865 MHz. The BaseStation for system B transmits in the frequency range 1950-1965 MHz and receives inthe range 1870-1885 MHz. The CDMA preferred set channel numbers for system Aare 25, 50, 75, 100, 125, 150, 175, 200, 225, 250, and 275 and for system B are 425,450, 475, 500, 525, 550, 575, 600, 625, 650, and 675. To calculate the centerfrequency of CDMA channel in MHz we substitute the preferred channel number, N,in 1850 +0.05N for BS receiving frequencies and 1930 + 0.05N for the BStransmitting frequencies. Note that the frequency spacing between the down and uplinks is 80 MHz for PCS applications.

Data Rate and Voice Activity FactorData rate varies depending on the type of Voice Encoder (VOCODER). The full datarate for the 8kbps and 13kbps VOCODERS are 9.6 kbps and 14.4 kbps, respectively.Within each data rate set, the user can transmit at full, half, quarter, or one eighth ratedepending on the voice activity (talking, pausing, or listening). These rates are 9.6,4.8, 2.4, 1.2 kbps and 14.4, 7.2, 3.6, 1.8 kbps for the 9.6 kbps and 14.4 kbps data ratesets, respectively. It has been estimated that about 24% of the call duration the usertransmits at full rate, 14% at half rate, 12% at fourth rate, and 50% at one-eighth rate.This yields a voice activity factor (VAF) of about 40%. It should be noted, however,that the VAF is a discrete random variable with mean = 0.4. The 13kbps VOCODERwill be used for the SPRINT SPECTRUM case.

Reverse and Forward Links Eb/No



Eb/No is the energy per bit to background noise plus inter-user interference requiredto achieve a given FER (e.g., 2%) and is dependent on the speed of the mobile, fadingcondition (multi-path) and the power profile of the resolvable multi-paths. Themaximum required Eb/No for the reverse link occurs for mobile speeds around 30km/h at 1900 MHz and around 60 km/h at 800 MHz.



The forward link usually requires a higher Eb/Io value for the same frame error rateperformance which can be attributed basically to: (1) Different interference levels seenby each receiver (2) Type of detection (coherent in the forward link and noncoherentin the reverse link) and (3) Different power control algorithms. For SPRINTSPECTRUM design, we will use 6.2 dB for both links (assuming that the reverse linkis the limiting case).

Mobile Transmit PowerThe maximum mobile transmitted power depends on the power class (I, II, III) of themobile. For link budget calculation purposes a value of 0.2 W (class III) is used. This200 mW power is equivalent to 10log(0.2) + 30 = 23 dBm.

Base Station Receiver Noise FigureThe Noise Figure (NF) is a measure of the noise added by a network (or transducer)to an RF signal passing through it. NF is usually defined in terms of signal-to-noiseratios at the input and output ports of the network. Noise Figure measured in dBs isdefined as 10log[(SNR)in/(SNR)out]. The exact value of NF depends on the equipment(i.e., manufacturing specific).

Cable, Connector and Duplexer LossesThis is the resultant loss in the BTS RX path due to above components, and a typicalloss of 3 dB has been assumed for calculation purposes. Actual losses for eachapproved site should be calculated using selected cable type, radius, length, andconnector type.

Body LossThis is the loss due to a hand-held mobile being used close to the human body causingsignal blockage and absorption.

Building Penetration LossThis is specific to the application and type and structure of the environment. Customerspecific values could be used depending on the requirement. The following values willbe used in calculating the power link budget for SPRINT SPECTRUM: 20 dB forDense Urban, 15 dB for Urban, 10 dB for Suburban, 8 dB for Rural (In-Vehicle), and0 dB for Rural (open).

Shadowing and Penetration Loss Standard DeviationSlow fading (shadowing) is assumed to be log-normal with standard deviation σ1.Shadowing is the local mean of the fast amplitude variation of the RF signal which isassumed to have Rayleigh distribution. A typical value for σ1of 8 dB has been usedfor calculation purposes. The signal upon penetrating a building will also experience a



loss which has a log-normal distribution with standard deviation = σ2. The composite

(effective) standard deviation due to shadowing and penetration loss is σ = σ σ12

22+ .

In our case, σ2 is 8 dB for in-building coverage, 4 dB for in-vehicle coverage, and 0dB for out-door coverage. It follows that σ is 11.3 dB for DU, U, SU, 8.9 dB forRural (in-vehicle), and 8 dB for Rural (out-door).

Quality of ServiceQuality of service (QOS) or coverage reliability of a cellular system is defined as theprobability of the instantaneous received signal power level greater than a threshold(Pth). If the local mean of the signal’s power has a log-normal distribution with medianµ dBm and standard deviation of σ dB, then QOS = Q[(µ - Pth)/σ]. Where

Q x e dyy

x( ) /= −∞∫1

22 2

π and (µ - Pth) is defined as the Fade Margin (FM). Note thatthe above definition is general which can be applied to calculate the QOS at the celledge or all over the coverage area.

Slow Fade (Shadow) MarginThis depends on the QOS at the cell edge and on the shadowing and penetrationstatistics (the composite standard deviation). For SPRINT SPECTRUM case, thefollowing values have been calculated and used in the link budget: 7.6 dB for DU, U,and SU, 6 dB for Rural In-Vehicle, and 5.4 dB for Rural Out-door.

Soft Hand-off GainThis depends on the shadowing statistics, QOS at cell edge, number of cells in softhand-off and the shadowing correlation between them. The signals from differentsectors (cells) are combined using maximal Ratio Combining algorithm (RAKEReceiver) that maximizes signal-to-noise ratio. Different soft hand-off types can beidentified:

• No HO: A subscriber is served by a single sector. (One channel element is required).

• Softer HO (Inter-sector hand-off): A subscriber is served by two sectors of the same cell. (One channel element is required). In this case the cell controls the hand-off process and provides a parallel path between the sectors. The MSCis informed of the hand-off activity but is not an active participant.

• Soft HO (or two-way soft-HO): A subscriber is served by two sectors from twodifferent cells. (Two channel elements are required). The MSC controls this hand-off process.

• Softer-Soft HO: A subscriber is served by two sectors of one cell and one sector of a second cell. (Two channel elements are required).



• Soft-Softer HO: A subscriber is served by two sectors of one cell and one sector of a second cell. (Two channel elements are required).

• Soft-Soft HO: A subscriber is served by three sectors from three different cells. (Three channel elements are required).

Cell Loading and Loading FactorLoading is a measure for the cell capacity. Every user, upon accessing the CDMAchannel, is considered as an interference source to all other users and contributes to anincrease in noise rise level above background noise (thermal noise). Cell loadingdefines the call blockage in CDMA. In contrast to FDMA and TDMA, CDMA offerssoft blockage since loading can be relaxed as desired. The load margin (in dB) due toloading is calculated as 10log(1-loading). A system loading of 50% degrades thesystem performance (i.e., reduces the cell coverage) by 3dB and 30% degrades theperformance by 1.55 dB. For the SPRINT SPECTRUM case, the system was designedfor 50% loading in DU, U, and SU sites, and 30% loading for Rural and Highwaysites. Note that the selection of the cell loading depends on the carried traffic by thatsector. For highly loaded cells, the network is designed with a high loading factor forthese cells in order to accommodate the high traffic demand. On the other hand, if thetraffic demand in some cells is expected to be light, then it is advantageous to designthese cells with a low loading factor. As you may have noticed that the cell coveragehas been extended by 10log(50/30) = 2.22 dB by reducing the loading factor from50% to 30%.

Forward Link Power Allocation and Walsh Code DesignationThe power allocation varies depending on the equipment and design features. ForSPRINT SPECTRUM case, the initial settings will be 20% for Pilot channel (WalshCode 0), 2% for Synchronization channel (Walsh Code 32), 4% for paging channels(up to 7 channels; Walsh Codes 1-7), and 74% for traffic channels (Walsh Codes 8-31,33-63). Note that if less than 7 paging channels are used, then the remaining channels(Walsh Codes and their power allocations) can be utilized as additional trafficchannels.

CDMA CapacityNumber of simultaneous users that can be served by each CDMA sector is given by

NW RE I

FVAF

S Sub

b

reuseG loading=

// 0

where

W/Rb : Processing Gain = 19.31 dB



Eb/Io : 6.2 dBFreuse : Frequency Reuse factor defined as the interference from other cells to

the interference in the desired cell. We will use Freuse of 63%.VAF : Voice Activity Factor = 40%.SG : Sectorization Gain = 2.55/3. That is, the capacity of a three-sector site is

not exactly three times that of an Omni-site because the RF coverage of the three sectors is not perfectly isolated.

Sloading :Loading Factor = 50% for DU, U, SU sites and 30% for Rural and Highway sites.

Using the values above we haveNu = 13 users/sector for DU, U, and SU sites, andNu= 8 users/sector for Rural and Highway sites.



II. Procedure for Running the CDMA Analysis Tool on PlaNET

The CDMA analysis tool can only be run after you spread the traffic. To spread the trafficor to do traffic analysis, please refer to the document "Spreading and analyzing thetraffic" - File2 or section III of this File “Controlling CDMA Design Parameters from theResults of the CDMA Analysis Tool” depending on the procedure you want to follow forspreading the traffic.

1. Clear Previous Analysis: Clear previous CDMA analysis and delete all L* and Q*files that belong to CDMA analysis from your current directory every time you run theCDMA analysis. The sizes of these files are large and can increase the probability ofsystem crash. The L* files are generated every time you run the analysis which contain thenecessary data to be used during the simulation . The data in these files is exported fromthe prediction and database files. The Q* files are the output files which contain the resultsof the analysis and are used in generating different types of plots and statistics reports.Saving these files will not help when you rerun or restart the analysis because the analysishas to be repeated every time you login to your system.

2. Size of analysis area: To avoid system crash, the size of the CDMA analysis area for100m clutter data resolution is advised to be less than 100Km X 100Km, although I havesucceeded in analyzing a window size of 190Km X 190Km. For 30m Clutter dataresolution, the processing time is 11.1 times that for 100m case. Therefore, thewindow size is advised to be reduced accordingly.

3. Parameter Settings: You may use different parameter settings for different classes ofsites by activating only those sites of interest and then applying the changes to each set atonce. Alternatively, you may change some of the CDMA parameter settings on site-by-site(or sector-by-sector) basis by choosing the site/sector ID from the CDMA main menu.

To change the settings• Select CDMA from Tools Menu.• Select Parameter Settings.• Runs: 15. (From the Main CDMA Menu).This factor is a tradeoff between the processing time and simulation accuracy. One run isequivalent to one Shot which is also equivalent to one random trial. Many of thesimulation variables are inherently random in nature, for example, the generated trafficfrom each bin. Therefore, to establish more reliable results, the number of Runs has to bemuch greater than 1. For large values of "Runs", we can then look at the results on anaverage basis.



Note: The CDMA plots are generated only from the results of the last run. The results inthe statistics reports are averaged over all random trials.



SYSTEM PARAMETERS• Chip Rate (Mc/s): 1.2288• Traffic Rate (kb/s): 14.4 for a 13 kb/s VOCODER• Paging Rate (kb/s): 4.8• Synchronous Rate (kb/s): 1.2• Fade Margin: Reduction in signal level as a result of fading that can occur before ahand-off process is initiated. i.e., the received signal at the edge will be degraded by theFade Margin value minus Soft Hand-off gain of the cell before a soft hand-off process istriggered.

Input 3.6 dB for Dense urban, Urban and Suburban sites2.0 dB for Rural On-Hwy sites, and1.4 dB for Rural In-Town (Out-door) sites.

Note: The calculations of the above fade margin values are based on 75% cell edgereliability, 11.3dB composite standard deviation for in-building, 8.9 dB for in-vehicle, and8 dB for outdoor.Note: Since the fade margin parameter can't be specified per site basis, I suggest todetermine first the category type of the majority of the sites in the analysis window andthen select the fade margin value as specified above.Note: The soft hand-off gain is assumed to be 4dB which has been applied across thewhole coverage area and has been included in above calculations.

ANALYSIS RUN LIMITS• Max. Sites per Bin: Number of sites that can be evaluated during the analysis of a

single bin. Input: 19• Max. Pathloss (dB): 200. A site will be excluded from the analysis if the pathloss

between its antenna and that particular bin is greater than 200 dB.• Max. Pathloss Diff. (dB): 100. A site will be excluded from the analysis if the

difference in pathloss between it and any other site in the list is greater than 100 dB.• Max. Memory Usage (Mbytes): 256. (Should be equal to the RAM size of your

machine).

MOBILE PARAMETERS• Maximum PA Power (dBm): Refer to mobile manufactures specifications. Input

Class III of 23 (dBm)• Minimum PA Power (dBm): -50• Antenna System Gain (dBi): 0• Body Loss: Input: 0 (dB)• Receiver Noise Figure (dB): 8• Forward Voice Eb/Io (dB): 6.2. The required Eb/Io at the mobile receiver (hence

called Forward Voice Eb/Io) for achieving a FER of 2%.• Percentages of Voice Channel Data Rates:



• Percentage Full Rate (%): 24• Percentage Half Rate (%): 14• Percentage Quarter Rate (%): 12• Percentage Eighth Rate (%): 50‡

This yields a VAF of 24 *1 +14*0.5 +12*0.25 + 50*0.125 ~ 40%‡

‡ Will be set automatically after applying the above edits.

SECTOR PARAMETERS

>> Base Station Parameters• Transmit Line Loss (dB): 3 (Default)• Receive Line Loss (dB): 3 (Default)Note: Use actual values for your sectors if known - see “Site Configuration Plan”.• Base Noise Figure (dB): 6.4

>> TMIT Power Parameters• Max. Pilot Power (dBm): 36.0

• Relative Min. (dB): -42• Power Initial (dB): -1.5

• Relative Voice Power (dB): -2• Relative Min. (dB): -10• Power Initial (dB): -7.2

• Relative Initial Paging Power (dB): -5.8• Relative Initial Synch. Power (dB): -11.4

>> Quality Parameters• Reverse Voice Eb/Nt (dB): 6.2• Target Pilot Ec/Io (dB): -13

>> Hand-off Parameters• T_ADD (dB): -14

T_ADD: pilot detection threshold. The pilot in the Neighboring or Remaining Set is added to the Mobile Station Candidate Set if its strength exceeds T_ADD. T_ADD is specified in units of -2dB Ec/Io. Based on Qualcomm studies an upper bound for T_ADD is -12dB(Ec/Io) and lower bound -17db (Ec/Io).

• T_DROP (dB): -16T_DROP: Pilot drop threshold. T_DROP is used by the mobile station to start a hand-off drop timer (T_TDROP) for pilots in the Active and Candidate Sets. T_DROP is also given in units of -2dB Ec/I0. Based on Qualcomm studies an upper bound for



T_DROP is -12dB(Ec/Io) and lower bound -20dB (Ec/Io).This parameter controlsthe soft hand-off area for a given sector.

• T_COMPARE (dB): -2.5This parameter is a comparison threshold between an Active Set Pilot versus a Candidate Set Pilot. Pilot Strength Measurement message is sent by the mobile station when the strength of a pilot in the Candidate Set exceeds that of a pilot in the Active Set by 0.5xT_COMP. The value of T_COMP should be set to prevent the mobile station from sending continuous Pilot Strength Measurement messages, as a result of small changes in strength between the pilots in the Active and Candidate Sets. This parameter can also be used to control the soft hand-off area for a given sector.

• Tick "Optimize Forward Link"

Note: Make sure that you check the edit box next to each variable you change for theedits to take place.Note: The CDMA parameter settings can be saved if a file has been specified in Files inthe CDMA main Menu.

4. Start the Analysis:

At this point you are ready to start the CDMA analysis.• Select Analyze the "Reverse & Forward Link" from the CDMA main menu.• Select "Analyze System".The processing time depends on the area, prediction size, # of sites in that area, # of Runs,and the available memory on your workstation. Roughly, it takes about 20 minutes toanalyze a window size of 15Km X 15Km (for 100m resolution). However, the processingtime grows exponentially with the increase in the area size and clutter data resolution. Theprocessing time for the same window size but with 30m clutter data resolution would beabout 3.5 hours.

5. Results of the Analysis:

a. Pictorial Results:From the CDMA Menu, click on "Display". Select one of the following:• Reverse Best Server• Reverse Path Loss• Reverse Hand-off Status

• No HO; Color: White• Softer HO; Color: Green• Soft HO; Color: Yellow• Softer-Soft HO; Color: Red



• Soft-Softer HO; Color: Red• Soft-Soft HO; Color: Blue

• Reverse Available Eb/Io: Sum of Eb/Io from all cells involved in hand-off.• Reverse Required Mobile ERP: The power-controlled transmitted mobile power

required to acquire the reverse link. Use Low = -10(or less down to -50), Step =1 (or2).

For High, use• Dense Urban: -0.6‡‡• Urban: 4.4• Suburban: 9.6• Rural On-HWY (In-Vehicle): 13• Rural In-Town (Outdoor): 21.6

‡‡: This number is calculated as follows: 23 dBm (maximum allowable mobile ERP) - 7.6dB (Fade Margin for Dense Urban area) - 20 dB (Building penetration loss for DenseUrban area) + 4 dB (Soft Hand-off gain). Similar calculations can be done for the othermorphologies.

Note: Specifying different values for the maximum mobile ERP as shown above requiresyou to plot the reverse link coverage five times corresponding to the five morphologies.Alternatively, you can specify only one maximum value (for example 23 dBm), but keep inmind that no coverage will be attained if the required mobile ERP is greater than -0.6 dBmfor a dense urban bin, 4.4 dBm for urban bin, and so on. If the second approach isfollowed, then the plots have to be interpreted carefully when presented to the customer.

• Forward Available Ec/Io: Sum of Ec/Io from all cells involved in hand-off. Use Low = -15, High = 0, Step = 1.

• Forward Receiver Power: Maximum received power at each bin• Forward Pilot Ec/Io: Ec/Io of the serving sector.• Traffic Demand: Erlangs/Sq.Km.• Traffic Gain: Gain in capacity due to power control algorithm.

b. Statistics ReportsFrom the CDMA main menu, click on "Statistics". Generate the Reverse link andForward link reports by clicking on the "Reverse Link Report" and "Forward LinkReport", respectively.

Note4: Don't regenerate the forward and reverse link statistics files in the same session asthis may lead to a system crash. Always close the old files before you generate the newones.



III. Controlling CDMA Design Parameters from the Results of the CDMA Analysis Tool

Introduction:At this stage of CDMA design for SPRINT SPECTRUM, we would like to rely more onthe CDMA tool for controlling some of the design parameters such as system loading (ornoise rise level due to loading), soft hand-off percentages, and reuse efficiency. Also, wewould like to know from CDMA tool if the coverage of the forward and reverse link areidentical as well as to ensure that the design is meeting the objectives and the reliabilitycriterion assumed in the link budget(i.e., the probability of service at the cell edge). Forinstance, changing the antenna tilting can limit the cell coverage and control the other-cellsinterference. Also, modifying the hand-off parameters and varying the antenna orientationcan control the soft hand-off region percentages and rates.

Therefore, using the CDMA tool on PlaNet, we would like to make sure that there is noexcessive amount of multiple access interference from other cells/sectors. We will use theFrequency Reuse (FR) factor as a measure for this interference. The FR factor is definedas 1/(1+f), where f is the fraction of other-cell inter-user interference with respect to thein-cell interference. A high FR factor is not always desirable nor achievable for every cellsince, in practical situations of uneven traffic distribution, if the other-cells interference fora particular cell is low (hence high FR), then the FR factor for some other cells will beenforced to be low. A feasible design would then require a moderate value for the FRfactor.

In our CDMA design, we have assumed f = 0.60, or FR = 0.63. This factor can beobtained for each sector from the Reverse Link Statistics Report after you run the CDMAanalysis.

Another parameter of interest to us is the soft hand-off percentage. A composite softhand-off of 50% of the total coverage area is desirable. The nominal values for the softhand-off percentages as specified in SPRINT SPECTRUM document “CDMA RFDESIGN SPECIFICATIONS” are:

% Subs in Softer Hand-off 20%% Subs in Soft Hand-off 20%% Subs in Soft-Softer Hand-off 5%% Subs in Three Way Soft Hand-off 5%

The soft hand-off percentages are a trade-off between performance quality (since SoftHand-off extends coverage at the cell edge by 4dB) and the cost of additional channel



elements. One additional channel element is required to achieve Soft, Soft-Softer, orSofter-Soft hand-off. Two additional channel elements are required to achieve Three Waysoft hand-off. Clearly, the latter soft hand-off type need to be minimized.

The Hand-off percentage distribution over different types of hand-off can be obtainedfrom the "Forward Link Statistics report" after you run the CDMA analysis. Our aim hereis to keep the percentage of "No Hand-off Area" at 50% on the average (not necessarilyon a per sector basis).

PROCEDURE:

1. Set number of Runs in the CDMA main menu equal to 15.

2. Spread the traffic. As you may have noticed when you spread the traffic for year 5that, due to random traffic distribution, some sectors captured more than 6.61 Erlangs(and hence required more than one RF carrier) than others. Other sectors, however,captured much smaller values than would be when the system operates eventually atfull load. Since the current CDMA tool doesn’t support multi-carrier simulation, thosesectors that have got more than 6.61 Erlangs for 50% sector loading (or 3.13 Erlangsfor 30% loading) will be overloaded and their coverage radii will be reducedaccordingly (remember that RF coverage will be reduced by 10log10[1-loading] dBdue to loading factor. To solve this, we will use traffic values that will eventually bethe actual sector loading when the network is fully loaded. On one hand, this methodprevents excessive sector loading due to the random distribution of traffic in theoriginal customer’s traffic mapping files. On the other hand, it doesn’t allow the use ofsmall traffic values due to an inappropriate choice of the traffic file. This methodguarantees an even distribution of the traffic and hence it become easier to fix FRfactor at about 63% (except for sites at the network boundary).The sector pole capacity for a processing gain of 19.31 dB, Eb/Io of 6.2 dB, voice activity factor of 40%, frequency reuse factor of 63%, and sectorization gain of 85% is 26 users. Therefore, assuming 1% blocking probability, one sector can support 6.61 Erlangs (or 13 users) for 50% loading and 3.13 Erlangs (or 8 users) for 30% loading.

2a. Create and index a Live Traffic File by following the procedure described in page 180 of MSI PLANET Training Manual - March 95.

2b. Input 6.61 Erlangs/sector for Dense Urban, Urban and Suburban sites.Input 3.13Erlangs/sector for Rural and Highway sites.Make sure that the file contains all your active sectors.

2c. Use eastmin, eastmax, northmin, and northmax to define the geographical area within which the traffic data will be spread. (These values can be obtained from Display Key). Update these values in your index file as you slide the CDMA analysis window. Alternatively, use one set for eastmin, eastmax, northmin, and



northmax such that all your active sites are within the dimensions you select. If the second approach is followed, then more processing time and memory size are required for spreading the traffic.

2d. Spread the traffic data by selecting the live traffic file you just created from the main menu Tools ⇒⇒ Traffic Load/Create ⇒⇒ Load Live Data. Select Use Available Clutter and the traffic will be spread over the area according to the pre-specifiedclutter weightings (see File2 - Spreading and Analyzing the Traffic).

3. Do the CDMA analysis for at least N cells. N depends on the morphological classification of the area. If the area consists of contiguous urban or rural sites, then N should be large enough to include the interference of at least the second tier. In this case, N = 19. For highways you can use smaller values for N. If in some situations there exists a very high antenna site relative to its neighbors and assuming that the coverage of that site has not been controlled by antenna tilting or any other means, thenthat site has to be included in the list and N has be increased to include the sites from the third tier.

4. Examine "FR" factor, Loading and "NO Hand-off" % values from the reverse link and forward link statistics reports.

4a. First, fix FR and Loading factors:Loading factor is the measure of the in-cell interference (noise rise) and FR is the measure for the other-cell interference with respect to the in-cell interference.If "FR" is NOT in the range [61%, 65%] averaged over all analyzed sectors and if"Loading" is greater than 60% averaged over DU,U, and SU analyzed sectors (or 38% averaged over Rural and Highway analyzed sectors) , then change one or more of the following parameters for the sectors that have values most deviated from the above nominal values- Repeat procedure until FR and Loading factors are within the above required ranges.

4a1. Sector orientation: Rotate sectors clock wise or counter clock wise by up to 600 for tri-sector sites so that the RF coverage can be reoriented and CDMA design parameters can be controlled. Note that rotating tri-sectors by 600 corresponds to site inversion beyond that the cell coverage goes back to the origin (starting from 00).

4a2. Antenna Tilting. Up to 5 degrees.The variation of this factor should be related to the antenna height, E-plane radiationpattern (vertical beam width), structure of the near surrounding area and whethertilting is achieved electrically or mechanically. To achieve a coverage radius of Rmeters or an antenna of height Hb, the tilting angle, ϕ, (measured from horizon) for a



flat earth is given by ϕ = tan-1 (Hb/R). i.e., for Hb : R of 1 : 20, ϕ ≈ 30; for Hb : R of1 : 10, ϕ ≈ 60.Note: Antenna tilting is implemented mechanically in PlaNet. However, a combination of electrical and mechanical tilting usually gives the best performance.

4a3. Antenna height (if applicable):Increasing/decreasing the antenna height by αα > (-1) will increase/decrease coverage by about 10log10(1+αα) dB. αα = 1 corresponds to doubling the antenna height; αα =(-1/2) corresponds to halving the antenna height.The dependency of the propagation loss on the base station antenna height, H, usingOkumura-Hata model is -(13.82+6.55log10d)log10(H), where d is distance in metersfrom base station to mobile station. If the antenna height is changed from Hold toHnew, then the difference in the cell coverage will be 20.4log10(Hnew/Hold). Therefore,the best you can achieve is 6dB/octave for doubling the antenna height. However, ithas been demonstrated that 3dB/octave is only attainable in mobile radioenvironment. In addition, loss due to the increase in the cable loss need to beincluded.

4b. Second, fix Hand-off percentage:If "NO Hand-off" is not in the range [49%, 52%] averaged over all analyzedsectors, then change T_Drop in the range [-17 dB, -10 dB] for the sectors thatare most deviated from the above nominal value- Repeat the process, if necessary, until the "No Hand-off" is in the above required range.

5. Update/Expand your list:Add new sites to the list and at the same time drop some sites from the list, if necessary. Drop sites that will not affect the remaining sites in the list and at the same time will not be affected by the new sites added to list. (In general, you can drop those sites at least at the second tier and farther with respect to the site in the core of the analysis). In short, at least N sites need to be kept in your list when you slide yourwindow.

6. Repeat steps 2-5 until "FR", Loading and "No hand-off" parameters are controlled for all sites.

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