The demand for nomadic communicating services has been on a uninterrupted rise all over the universe mounting from 500 million endorsers a decennary ago to 4.6 billion in 2009 [ 1 ] This rise accompanied with competition among web suppliers and users demand for higher information rate at lower cost lead to uninterrupted development in telecommunication engineerings. The thrust to maximise the available bandwidth has seen the engineerings evolve from first coevals ( 1G ) and 2nd coevals ( 2G ) webs that is wholly circuit switched to 2.5G and 3G webs that are both circuit and package switched and traveling to 4G that is wholly packet switched. In parallel with this is besides the displacement from FDMA and TDMA techniques to CDMA techniques which provides spectrum efficiency. In utilizing codifications to specify user channels, this multiplexing technique provides solution for the of all time increasing figure of endorsers and holds much chance for the hereafter of telecommunication which is the 4G. The CDMA technique as employed in 2G and 3G is used in this undertaking for a design of 10kbps voice merely web and multiple services web of 10kbps voice and 150kbps non-real clip informations and are hereby discussed.
The CDMA web designs proposed in this undertaking exploits the advantages of public presentation sweetening techniques such as aerial sectoring, soft handoff and voice silence sensing. The flexibleness in managing informations rates and soft barricading capablenesss makes the designs robust and efficient.
Option one is a 2G web which uses a nominal bandwidth of 2MHz and bit rate of 1.664Mcps to supply quality voice merely web with barricading chance of 1 % . This requires about 276 cell sites to cover Orange Island with 204 base Stationss located in the City centre an country of 100km2. The suburban and sparsely populated countries assumed to be 400km2 and 1000km2 required 64 and 8 base Stationss severally. OQPSK is the transition technique uplink where the intervention is worse to guarantee changeless amplitude with limited stage fluctuation while QPSK is used downlink, keeping the same transmittal rate and heightening spectral efficiency. Cyclic coding with 24 spots CRC is used for mistake sensing to guarantee maximal sensing in the instance of worst attenuation ( burst mistakes ) and a whirl encoder of rate 1/3 K =7 is used for mistake rectification.
Option two requires a nominal bandwidth of 4.6MHz with bit rate of 3.744Mcps in a individual bearer three sector cell system and will efficaciously supply voice and informations services to about 145,000 users in all the parts of the Island. The figure of basal station required is 111, 45 and 6 for the metropolis Centre, suburban and sparsely populated countries severally. QPSK with coherency demodulation is the transition techniques for uplink and downlink, keeping the same transmittal rate on both links and supplying spectral efficiency with enhanced signal sensing.
A rate 1/3 turbo codification and cyclic codification of 12 spots CRC is employed to supply high mistake sensing and rectification. The hardiness and efficiency of turbo codification is about the highest. [ 2 ]
1.2 BRIEF HISTORY AND LITERATURE REVIEW
The practical application of spread spectrum engineering can be traced back to military operations since World War II. [ 3 ] Until Dixon ‘s publications in 1976, most literature on spread spectrum engineering were non detailed as application information were classified. [ 4 ] The mandate for civil usage of the engineering harmonizing to [ 4 ] was obtained in 1985 with Qualcomm as one of the pioneering company. The 2G standard IS-95 was published in 1993 and revised in 1995 with a 2nd alteration standardising IS-95B referred to as 2.5G. [ 5 ] The 3GPP and 3GPP2 established in 1998 defined the UMTS for WCDMA ( 3G web ) in Release 99 and standardized CDMA2000 severally while the LTE ( 3GPP long term development ) and LTE advanced are mapping CDMA into the 4th coevals webs. [ 6 ]
1.3 DESIGN SPECIFICATION
To plan a CDMA based nomadic communicating system for a major metropolis Voda in Orange Island covering an country of 1500km2 with a dumbly populated Centre of about 100km2. The denseness of users in the metropolis Centre, the suburban and the sparsely populated countries are 1000/km2, 100/km2 and 5/km2 severally. Available frequence sets are 1920 – 1980MHz for uplink and 2110 – 2170MHz for the downlink. The design is to cover two options: a voice merely web with user informations rate of 10kbps and a 10kbps voice with 150kbps non-realtime information web. Extra premises:
The suburban and sparsely populated countries are 400km2 and 1000km2 severally.
The physical terrain of the countries is considered to be averagely apparent with no extra way loss or web obstructor by high lands.
1.4 COMPARATIVE COST ANALYSIS
In 2001, GSM licensing was done in Nigeria, at a license monetary value of $ 285 million [ 7 ] [ 8 ] ( about N 39.9 billion @ $ 1 = N 140 ) for 40MHz ( 2x5MHz in the 900MHz set and 2x15MHz in the 1800MHz set [ 9 ] ) . The cost per Hertz = N 997.5. The cost of constructing a cell site is about $ 230,000 [ 7 ] excepting the cost of rental for the land which is about $ 21,500. Entire site cost is about $ 251,500 ( N 35.21 million ) . This means that the cost of 35.3kHz is tantamount to the cost of 1 cell site and 1MHz comparable to 28 cell sites.
The hundred-and-fiftieth unit of ammunition of command ended the UK licensing in 2000 [ 10 ] with mean cost per Hertz being ?161.8 as shown in table 1.
The mean cost of constructing a new site ranges from ?220,000 – ?240,000 [ 12 ] or a‚¬266,000 [ 13 ] .
Therefore the cost of 1.422kHz is tantamount to the cost of 1 cell site and 1MHz comparable to 703 cell sites!
Table 1: Cost of 3G bandwidth ( Beginnings: [ 11 ] & A ; [ 12 ] )
1.5 DESIGN CONSIDERATIONS
The analysis above nowadays the extremes of the cost of bandwidth comparative to cell site. The undertaking at manus is to present a quality web services to the people of Voda, guaranting equal coverage utilizing the best optimisation method and at a well low cost. Bandwidths are expensive but in seeking to salvage in bandwidth, more base Stationss are required which is a comparatively low cost. So trade-offs has to be made in the most economical manner to guarantee conservative usage of the bandwidth. Based on these considerations, the undermentioned determinations are made:
The bit rates and bandwidths are well chosen to cut down cost in hardware, cell site acquisition and bandwidth.
The base Stationss can be shared with other suppliers to retrieve some of the cost.
Excess cost of bandwidth in option 2 can be recovered from information users.
The cryptography strategies are maximized to heighten system capacity and service quality, and to avoid long hold due to ARQ for information services.
Barricading chance is set at 1 % ( considered extremely satisfactory from my interview and interaction with users ) .
2.0 CIRCUIT SWITCHED CDMA NETWORK FOR VOICE SERVICES
Figure 1 ( matlab codification located in appendix 1 ) shows that as user information rate additions, the figure of users that can be accommodated at a peculiar bandwidth lessenings.
Fig.1: Number of users as a map of bandwidth Pole Capacity
To enable us find the effectual bandwidth for the system, we start from the required user informations rate and cipher what the information rate at the base station should be. Figure 2 is a block diagram of uplink web for voice merely service. A coded voice signal to be transmitted in a 10ms frame construction at 10kbps contains 100 spots. The frame is coded for mistake sensing adding 24 cheque spots and forwarded for mistake rectification coding. The encoder is a rate 1/3 whirl encoder which is described below in subdivision 2.1. The tail spots appended to the information from the encoder is 6 ensuing to entire user information rate of 13kbps. The end product encoded sequence of 390 spots ( 130 x 3 ) is interleaved to cut down the consequence of burst mistakes. The interleaved end product of 39kbps is used to bring forth Walsh codification ( every 6 spots of the 390 is used to bring forth a 64 spot sequence ) ; the ensuing signal is 4160 spots at a information rate of 416kbps. The end product is fed into a information explosion randomizer which regulates the sender power ( turns the sender away or to a power save manner when the entire user information rate is less than 13kbps ) . With distributing factor of 128 for a entire user information rate of 13kbps, the ensuing bit rate is 1.664Mcps.
BT= Baud rate ( 1+r ) aˆ¦aˆ¦.. ( 1 )
For a roll-off factor of 0.20 utilizing a root raised cosine, BT = 1.9968MHz. The nominal bandwidth is set to 2MHz including guard sets.
Fig. 2: Uplink web ( Mobile to Base station ) Adapted from [ 14 ]
The downlink transmittal shown in figure 3 is about the same as in the uplink except that a rate A? encoder is used since there are less interference downlink and 4 power control spots ( 400bps, utilizing a decimator of 65 on the 26kbps informations rate ) are multiplexed with the informations to be transmitted which is at the rate of 26kbps. The 64 Walsh codifications generated at the bit rate of 1.664Mcps define the downlink channels and are used to distribute the 26kbps signal ensuing to a distributing addition of 64. A sum of 55 traffic channels are available to the base station, 1 pilot channel, 1 synchronism channel and 7 paging channels. Besides the transition technique in the downlink is different without a hold in the quadrature signal.
Fig. 3: Downlink web ( Base station to Mobile ) Adapted from [ 14 ]
2.1 Cryptography Technique
Cyclic coding with 24 cheque spots reduces the chance of undetected mistake to 10-24 [ 14 ] and a K = 7 rate 1/3 whirl programmer provides error rectification. The efficiency of the whirl encoder additions with diminishing rate and increasing restraint length. [ 14 ] With a big barricading factor ( figure of figures in a block ) , the efficiency of the coding tends to maximum. These picks guarantee that the spot error rate is non more than 10-3 and any frame with uncorrected mistake is dropped for worst instance attenuation.
2.2 MODULATION TECHNIQUE
The transition technique for the uplink is OQPSK. CDMA is an intervention limited system and this is worse on the uplink. OQPSK will supply enhanced signal sensing at the base station since the signals are of changeless amplitude and stage fluctuation is less than. This reduces the spot error rate and increases the quality of the service. In the downlink where intervention is less, transition is QPSK. It is of import to observe that consistent sensing is non required with these transition techniques and the baseband signal for the uplink or downlink is non more than 1.1MHz ( half the transmittal bandwidth for a BPSK ) taking to heighten spectral efficiency.
2.3 CELL CAPACITY
The nexus budget for the uplink and the downlink are located in appendix 2 and 3 severally. The concluding way loss allowed in the uplink is 140.5dB and 157.5dB for the downlink. Since the allowed way loss for the uplink is less, the system is said to be uplink limited
The Okumura – Hata extension theoretical account as used in [ 15 ] for a base station antenna tallness of 30m, nomadic station aerial tallness of 1.5m relates the allowed way loss in dubnium ( L ) and the cell scope in kilometer ( R ) by:
L1 = 137.4 + 35.2 aˆ¦aˆ¦aˆ¦ ( 2 )
If we provide a rectification factor of 8dB for the suburban part [ 15 ] and 27dB for the sparsely populated country [ 16 ] , for the suburban equation ( 1 ) becomes
L2 = 129.4 + 35.2 aˆ¦aˆ¦aˆ¦ ( 3 )
and for the sparsely populated country
L3 = 110.4 + 35.2 aˆ¦aˆ¦aˆ¦ ( 4 )
for L = 140.5dB, the scope R1, R2 and R3 for the dumbly populated, suburban and sparsely populated countries severally corresponds to 1.225km, 2.067km and 7.163km. These values give bounds in footings of way loss ( coverage ) . However, we need to look into restriction due to capacity.
The figure of users per cell ( individual bearer one sector ) in the uplink is given by:
NUL = + 1aˆ¦aˆ¦aˆ¦ . ( 5 )
where W= bit rate ; R = user spot rate ; = seize with teeth energy to Interference spectral denseness ; = Interference from other cells and = activity factor of the user.
For voice service with: W=1.664Mcps, R = 10kbps, = 7dB ( 5 ) for a vehicular user at 120km/h, I?=50 % ( 0.5 ) and =65 % ( 0.65 ) ,
NUL a‰?35 user channels.
In the downlink, the capacity of a individual bearer one sector cell is given as:
NDL = + 1aˆ¦aˆ¦aˆ¦ . ( 6 )
where ???¶ ( orthogonality factor due to imperfect power control ) = 0.4.
NDL a‰? 48 user channels.
The figures calculated above are referred to as pole capacity matching to 100 % burden of the cell. This nevertheless is non practical and 6dB noise rise is provided for as intervention border in the nexus budget corresponds to 75 % burden factor ( I·L ) . [ 15 ]
Actual capacity in the uplink is given by:
NUL x I·L… … … ( 7 )
From equation ( 7 ) , NUL a‰? 26 user channels & A ; NDL a‰? 38 user channels.
From the foregoing, the system is wholly uplink limited in capacity and coverage. Therefore the design will concentrate on the uplink.
Fig. 4: Cell sectoring
For a individual bearer three sector cell as in figure 4, the uplink capacity is 26 ten 3 = 79 user channels.
2.4 CAPACITY IMPROVEMENT
For the soft capacity of the system, the Erlang tabular array will non give an optimal consequence. [ 15 ] This is because if intervention is less in the surrounding cells, the referent cell ‘s capacity additions. Using the process summarised in [ 15 ] and located in appendix 1, the soft capacity is calculated as in table 2 for barricading chance of 1 % .
Table 2: Erlang computation for soft capacity
2.4 DIMENSIONING OF CELL SITE
The mean minute of usage for cell phone call is 475 proceedingss per month for a keeping clip of 3.25 proceedingss, intending 146 calls per month. [ 16 ]
On mean 90 % of the traffic is during the on the job yearss ( 21 yearss ) in a month. [ 17 ] This consequences to average of 6 calls /day/subscriber. Averagely, 2 of the calls are made during the busy hr. [ 18 ]
The traffic Erlang for a individual user = aˆ¦aˆ¦aˆ¦aˆ¦ ( 8 )
With the figures specified above, equation ( 8 ) gives 0.1083 Erlang of traffic
The user denseness in the metropolis Centre = 1000users/km2.
Traffic denseness = 1000 ten 0.1083 = 108.33erlang/km2.
Area of a cell = Soft capacity / Traffic denseness
= 67.69erlang / 108.33erlang/km2 = 0.625km2
Using the Hexagonal form theoretical account of cell dimension, the scope of the cell = = 0.490km ( good within the scope for maximal path loss 1.225km ) .
Number of cells in the metropolis Centre = 100km2 / 0.490km2 = 204 cell sites
The user denseness in the suburban country = 100users/km2.
Traffic denseness = 100 x 0.1083 = 10.83erlang/km2.
Area of a cell = Soft capacity / Traffic denseness
= 67.69erlang / 10.83erlang/km2 = 6.25km2
The scope of the cell = 1.55km ( still within the scope for maximal path loss 2.067km ) .
Number of cells in the suburban country = 400km2 / 6.25km2 = 64 cell sites
The user denseness in the sparsely populated country = 5users/km2.
Traffic denseness = 5 x 0.1083 = 0.5415erlang/km2.
Area of a cell = Soft capacity / Traffic denseness
= 67.69erlang / 0.5415erlang/km2 = 125.0km2
The scope of the cell = 6.934km ( less than nexus budget value of scope for maximal path loss 7.163km ) .
Number of cells in the suburban country = 1000km2 / 125km2 = 8 cell sites
Sum of 276 cell sites required to cover Voda in Orange Island.
3.0 WCDMA ( 3G ) Network
Fig. 6: Uplink web for information traffic ( Mobile to Base station )
Figure 6 is the uplink web diagram of the design for a nomadic communicating system capable of supplying 10kbps voice service and 150kbps non-realtime informations service. Get downing with a user who is uploading informations at 150kbps rate, a 10ms frame incorporating 1500 spots undergoes cyclic coding with extra 12 CRC spots appended to it. The 1512 spots are segmented into 4 blocks of 378bits so as to fit the latency of the interleaver ( 390bits ) in the turbo encoder. Each block is channel coded utilizing the rate 1/3 turbo encoder described in subdivision 3.1. The end product of the encoder is 4 blocks 1170 spots made up of the original 378 spots plus 12 tail spots multiplied by 3. The entire end product spot for wireless frame equalisation is 4680 spots. The spots are interleaved twice ( depending on the transmittal clip interval ) and mapped onto the physical bed. The spots are spread with channelisation codification dividing the information and the control channels and the spreading factor is 8 for informations. The end product bit rate is 3.744Mcps and corresponds to the nominal bandwidth of about 4.6MHz utilizing equation ( 1 ) . The I and Q codifications are multiplexed to avoid intervention in the system during discontinuous transmittal before informations is dispersed with complex scrambling codification. The scrambled signal so modulates the bearer for transmittal. The downlink operation is about the same as the uplink with QPSK used in both the downlink and uplink.
The web diagram for the uplink voice traffic is shown in figure 7. The web is circuit switched and cleavage and equalisation procedures are non involved. Besides skipped is the first interleaving to avoid holds that will degrade the quality of the voice service.
Fig. 7: Uplink web for voice traffic ( Mobile to Base station )
3.1 Cryptography Technique
A 12 spot CRC codification is used for mistake sensing to cut down the proportion of undetected mistake in instance of terrible melting to 2-12 [ 14 ] sing the sum of informations involved.
The turbo cryptography is one of the most efficient in mistake rectification with BER lower than 10-5 and Eb/N0 of 0.7dB. [ 2 ] Figure 8 shows a block diagram of the turbo codification. The parallel affiliated encoders are convolution encoders of K =7 ensuing to entire tail spot of 12 spots per codification block. The cryptography is systematic and recursive while decrypting is by uninterrupted loop. Table 3 shows the elaborate end product of the encoding strategy. The low latency of the interleaver 390 spots allows a maximal hold of 39ms for the 10kbps voice signal, doing the encoder suitable for both informations and voice.
Table 3: Rate 1/3 Turbo codification ( Max. size of codification Block 390 ( i.e. 378 + 2 X 6 tail spots ) )
M U L T P L E X E R
Fig. 8: Rate 1/3 Turbo Encoder ( Parallel Concatenated Convolutional encoder ) . [ 2 ]
3.2 MODULATION TECHNIQUE
QPSK with consistent sensing is preferred as the modulation/demodulation technique for this design to maximise spectral efficiency while keeping unvarying spreading factor ( 96 & A ; 8 ) and informations rate ( 10kbps & A ; 150kbps ) in the uplink and downlink waies. The spot error rate public presentation of this technique is high because the signal does non endure from the debasement experienced when differential sensing is used. [ 18 ]
3.3 CELL CAPACITY AND LOADING
The nexus budget computation for option 2 is located appendix 4 and 5 and coverage restriction due to maximal path loss is uplink edge.
At the allowed extension losingss are 140.5dB, from equations ( 2 ) – ( 4 ) , the scope of the cells corresponds to 1.07km, 2.36km and 9.31km for the metropolis Centre, the suburban country and the sparsely populated country severally. These values give bounds in footings of way loss ( coverage ) , but we need to look into restriction due to capacity to find the optimal size of the cells.
For voice merely service with: W=3.744Mcps, R = 10kbps, = 7dB ( 5 ) , I?=50 % ( 0.5 ) and =65 % ( 0.65 i.e. 50 % plus overhead during DTX ) , utilizing equation ( 5 ) the figure of users per cell ( individual bearer one sector ) in the uplink is:
NUL a‰?77 user channels.
For informations merely service with: W=3.744Mcps, R = 150kbps, = 1dB ( 1.259 ) , I?=50 % ( 0.5 ) and =100 % ( 1.0 ) ,
NUL a‰?14 user channels.
In the downlink, utilizing equation ( 6 ) , the capacity of a individual bearer one sector cell for voice merely service with: W=3.744Mcps, R = 10kbps, = 7dB ( 5 ) , I?=50 % ( 0.5 ) , =65 % ( 0.65 ) & A ; ???¶ = 0.4,
NDL a‰? 105 user channels.
For informations merely service with: W=3.744Mcps, R = 150kbps, = 1dB ( 1.259 ) , I?=50 % ( 0.5 ) , =100 % ( 1.0 ) & A ; ???¶ = 0.4,
NDL a‰? 19 user channels.
The computations show that in both capacity and coverage, we are uplink limited. The design will concentrate on the uplink.
The pole capacity calculated supra is non practical as it assumes that the nomadic station has infinite transmittal power and intervention at node B receiving system goes to eternity. [ 19 ] The 6dB noise rise corresponds to 75 % burden factor ( I·L ) . [ 15 ]
Actual capacity in the uplink utilizing equation ( 7 ) corresponds to about 58 voice merely channels and 11 informations channels.
The throughput in a cell is given by: = R x N ( 1- BLER ) … … … .. ( 9 )
where BLER = block mistake chance. For BLER of 1 % and 10 % for voice and informations severally, = 574.2kbps & A ; 1485kbps in the uplink.
For a individual bearer 3 sector cell, the figure of channels scale to 174 voice channels and 33 informations channels, while the throughput graduated table to 1.723Mbps and 4.455Mbps in the uplink.
3.5 MULTIPLE SERVICES ( 10kbps voice and 150kbps non-real clip informations )
So far in the design, we have been sing the web in footings of individual services ( voice or information ) . When assorted services are provided by a web, the WCDMA cell capacity can non be referred to as a individual figure but a capacity part. [ 19 ] Figure 9 shows the capacity parts for pole capacity and 75 % burden of the cell ( matlab codification in appendix 1 ) .Every point in the edge represents a peculiar capacity mix for both services. The utmost instances of the edge at 75 % burden is 174 voice user channels and no informations user channel and 33 informations user channels and no voice user channel.
To come on in the design, we need to specify a traffic mix to enable capacity allotment and hence dimensioning of the cell. Priority is given to voice services which is more on demand. The point A in figure 8 defines a capacity resource agenda of 63 % for voice service and 37 % for information service which corresponds to about 109 voice user channels and 12 informations user channels ( throughput of 1,648,350bps out of the 4.455Mbps ) .
Fig. 9: Uplink Capacity Region for Voice and Packet switched informations Mixed Traffic
3.4 CAPACITY IMPROVEMENT
The soft capacity is shown below in table 3 utilizing the process in appendix 1 for barricading chance of 1 % . Note that there is no soft capacity for the package switched informations as shown in table 4 and figure 10.
Table 4: Erlang computation for soft capacity
Fig.10: Addition in Erlang for voice services due to Interference sharing
3.5 CELL DIMENSIONING
The traffic strength ( A ) as calculated for soft capacity is 96.353 Erlang.
The mean figure of call efforts per unit clip ( I» ) is given by: where 1/Aµ is the mean call length. Using the same retention clip and busy hr call rate as in subdivision 2.4, I» = 29.647 calls/minute.
The figure of endorsers that can be accommodated in a cell becomes 29.647 ten 30 = 889 users.
The medium rate of informations use is at 10Mbits per twenty-four hours. [ 12 ] Besides the busy hr tendency is the same for the same category of users ( 33 % of use in a twenty-four hours during busy hr as estimated for voice services ) . The mean use is about 3.3Mbits per hr and 916 spots per second.
With the throughput of 1,648,350bps, the figure of users that can be accommodated in a cell is calculated as 1,648,350/916 = 1799 users. If we provide for burstiness factor [ 20 ] of 2, this will be 899 users
Continuing with the hexangular form theoretical account. The country of a hexagon is given by 2.6R2. If 899 users may be accommodated in a cell, this means 346/R2 users per unit country.
For the dumbly populated country, 346/R2 = 1000 users/km2 giving R = 0.588km ( good within the maximal way loss calculated for this country as 1.07km ) .
Area of cell = 0.899km2
Number of cell sites = 100km2/0.899km2 a‰? 111 cell sites
For the suburban country, 346/R2 = 100 users/km2 giving R = 1.86km ( still within the maximal way loss for this country calculated as 2.36km ) .
Area of cell = 9.00km2
Number of cell sites = 400km2/9.00km2 a‰? 45 cell sites
For the sparsely populated country, 346/R2 = 5 users/km2 giving R = 8.319km ( still within the maximal way loss for this country calculated for this country as 9.31km ) .
Area of cell = 180.00km2
Number of cell sites = 1000km2/180.00km2 a‰? 6 cell sites
Sum of 121 cell sites required to cover Voda in Orange Island.
3.7 EXPANSION Plan
Expansion in the metropolis Centre will be covered through cell layering. Microcells and picocells will be installed where necessary to supply web for less nomadic users along the streets and in hot musca volitanss. The suburban and the sparsely populated countries can suit more macrocells if population of users addition. However, a major growing in the figure of users may necessitate establishing a 2nd bearer.
4.0 TOWARDS 4G
The outlook is high for the hereafter with recent technological promotions. A entire package switched web utilizing cyberspace protocols is to be deployed for voice, picture and informations webs maximising the usage of the available spectrum while availing users with really high information rates at low cost. With the mark informations rate already achieved in WiMax ( world-wide interoperability for microwave entree ) and the advancement made in WOBAN ( Hybrid Wireless-Optical Broadband Access Network ) , it will be virtually possible to supply any information rate on demand for imaginable user services.
In this undertaking, two web designs for a voice merely service and voice and informations services utilizing code division multiplexing entree was presented for a coverage country of 1500km2 with approximately 145,000 endorsers. Cost analysis was performed to find the comparative cost of bandwidth to establish station site to enable good determination and tradeoffs. Commissariats were made for the effects of attenuation, busy hr traffic and bursty informations to guarantee that a robust web that will present quality service to the user at a low cost is provided. Link budget computations were done to guarantee equal coverage of the cell borders and allowance made for enlargement. The design was concluded with a brief treatment of outlook on the hereafter of nomadic communicating.
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% Bandwidth relationship with figure of users
N1= ( ( w/30832.21 ) ) ;
N1R = ( N1*.75 ) ;
N2= ( ( w/283258.22 ) ) ;
N2R = ( N2*.75 ) ;
figure ( 1 )
secret plan ( N1, tungsten, ‘kd- ‘ ) ; xlabel ( ‘Number of users ‘ ) ; ylabel ( ‘Bandwidth ‘ ) ;
rubric ( ‘Bandwidth Pole Capacity ‘ ) ; grid on ; rapid climb on ; keep on ;
secret plan ( N2, tungsten, ‘rs- ‘ ) ;
fable ( ‘Number of 10kbps voice users ‘ , ‘Number of 150kbps PS information users ‘ )
figure ( 2 )
secret plan ( N1R, tungsten, ‘bs- ‘ ) ; xlabel ( ‘Number of users ‘ ) ; ylabel ( ‘Bandwidth ‘ ) ;
rubric ( ‘Bandwidth 75 % Loading Capacity ‘ ) ; grid on ; rapid climb on ; keep on ;
secret plan ( N2R, tungsten, ‘rd- ‘ ) ;
fable ( ‘Number of 10kbps voice users ‘ , ‘Number of 150kbps PS information users ‘ )
% Capacity Region Ploting
figure ( 1 )
secret plan ( x1, y1, ‘-bd ‘ ) ; xlabel ( ‘Number of 10kbps voice users ‘ ) ;
ylabel ( ‘Number of 150kbps PS information users ‘ ) ;
rubric ( ‘Uplink Capacity Region ‘ ) ; grid on ; rapid climb on ; keep on ;
secret plan ( x2, y2, ‘-rh ‘ ) ; fable ( ‘Pole Capacity ‘ , ’75 Percent Loading ‘ )
Procedure for gauging Soft capacity [ 15 ] .
1.Calculate the figure of channels per cell, N, in the every bit laden instance, based on the
uplink burden factor
2. Multiply that figure of channels by 1 + to obtain the entire channel pool in the soft
3. Calculate the maximal offered traffic from the Erlang B expression.
4. Divide the Erlang capacity by 1 + .
5. The trunking efficiency is defined as the difficult out of use capacity divided by the figure
UPLINK BUDGET FOR OPTION 1 ( VOICE ONLY )
Premises for nomadic station
Max. Tx. Power: 23 dBm ( 200mW category 3 device )
Antenna addition: 0 dBi
Body loss: 3 dubnium
Premises for Base station
Amplifier Noise Figure: 4dB
Antenna addition: 18 dBi ( 3 sector base station )
RequirementA : 7 dubnium
Cable loss: 2 dubnium
10kbps voice service ( 120km/h in-car user with soft handoff in the Capacity limited country ( City centre ) )
Transmitter ( Mobile station )
Max. Mobile Tx. Power [ dBm ] 23.0 a
Mobile Antenna addition [ dBi ] 0.0 B
Body loss [ dB ] 3.0 degree Celsius
Equivalent Isotropic Radiated Power ( EIRP ) [ dBm ] 20.0 vitamin D = a +b – degree Celsius
Receiver ( Base station )
Thermal noise denseness [ dBm/Hz ] -174.0 vitamin E ( KTBn where Bn =1Hz )
Base station Receiver Noise Figure [ dubnium ] 4.0 degree Fahrenheit
Receiver Noise denseness [ dBm/Hz ] -170.0 g = vitamin E + degree Fahrenheit
Receiver Noise power [ dBm ] -107.8 H = g +
Interference border [ dubnium ] 6.0 I ( 75 % lading upper limit )
Entire effectual noise + Interference [ dBm ] -101.8 J = H +i
Processing addition [ dubnium ] 22.2 K =
Required [ dubnium ] 7.0 cubic decimeter ( dependent on service )
Receiver sensitiveness [ dBm ] -117.0 m = cubic decimeter – K + J
Base station antenna derive [ dBi ] 18.0 Ns
Cable loss in the base station [ dubnium ] 2.0 O
Fast melting border [ dubnium ] 0.0 P
Maximal way loss [ dB ] 153.0 Q = d – m + n – o – P
Log normal melting border [ dubnium ] 7.5 R ( 93.4 % coverage prob. )
Soft & A ; Softer hand-off addition [ dB ] 3.0 s
In-car loss [ dB ] 8.0 T
Constructing Penetration loss [ dB ] 0.0 U
Allowed Propagation loss [ dB ] 140.5 V = q – R + s – T – U