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3G Speech Coverage3G Speech CoverageWCDMA Link Budget Speech Service Urban macrocellsUrban macrocellsUrban macrocells1 % FER target Uplink Uplink UplinkMax load 30% 50% 70%Max. TX Power per channel [W] 0.125 0.125 0.125As above in dBm 21.0 21.0 21.0 aTX Antenna Gain [dB] 0.0 0.0 0.0 bBody loss of MS in UL / Cable loss of BS in DL [dB] 2.0 2.0 2.0 cTransmit EIRP per channel [dBm] 19.0 19.0 19.0 d = a + b - c
Thermal Noise Density [dBm/Hz] -174.0 -174.0 -174.0 eReceiver Noise Figure [dB] 5.0 5.0 5.0 fReceiver Noise Density No [dBm/Hz] -169.0 -169.0 -169.0 g = e + fRise Over themal (Io+No)/No [dB] 1.5 3.0 5.2 hTotal interference density : Io = (1-a) Ior + Ioc [dBm/Hz] -172.7 -169.0 -165.3 i = 10*log( 10 (̂(h+g)/10)-10 (̂g/10) )Total effective noise + interference density : Io + No [dBm/Hz] -167.5 -166.0 -163.8 j = 10*log( 10 (̂i/10)+10 (̂g/10) )Processing gain [dB] 25.0 25.0 25.0 k = 10*log(3840/12.2)Required Eb/(No+Io) [dB] 4.0 4.0 4.0 m
Receiver sensitivity [dBm] -122.6 -121.1 -118.9 n = m-k+j + 10*log10(3840000)SHO Gain [dB], multi-cell 2.0 2.0 2.0 tRX Antenna Gain [dB] 20.5 20.5 20.5 oCable loss of BS in UL / Body loss of MS in DL [dB] 2.0 2.0 2.0 pTPC headroom [dB] 4.0 4.0 4.0 qMax. path loss [dB] 158.1 156.6 154.4 r = d - n + o - p + q +t
Coverage Probability [%] 80 80 80Log Normal Fade Constant [dB] 12 12 12Propagatiom odel exponent 3.38 3.38 3.38Log Normal Fade Margin [dB] 4.4 4.4 4.4 sBS antenna heigh 40 40 40MS antenna height 1.5 1.5 1.5Area type correction 0 0 0 UrbanIndoor Loss [dB] 15.0 15.0 15.0 u
3G data Coverage3G data CoverageWCDMA Link Budget Load =50 % Urban macrocellsUrban macrocellsUrban macrocells Uplink Uplink UplinkService, kbits/s 64.00 144.00 384.00Max. TX Power per channel [W] 0.25 0.25 0.25As above in dBm 24.0 24.0 24.0 aTX Antenna Gain [dB] 0.0 0.0 0.0 bBody loss of MS in UL / Cable loss of BS in DL [dB] 0.0 0.0 0.0 cTransmit EIRP per channel [dBm] 24.0 24.0 24.0 d = a + b - c
Thermal Noise Density [dBm/Hz] -174.0 -174.0 -174.0 eReceiver Noise Figure [dB] 5.0 5.0 5.0 fReceiver Noise Density No [dBm/Hz] -169.0 -169.0 -169.0 g = e + fRise Over themal (Io+No)/No [dB] 3.0 3.0 3.0 h Total interference density : Io = (1-a) Ior + Ioc [dBm/Hz] -169.0 -169.0 -169.0 i = 10*log( 10 (̂(h+g)/10)-10 (̂g/10) )Total effective noise + interference density : Io + No [dBm/Hz] -166.0 -166.0 -166.0 j = 10*log( 10 (̂i/10)+10 (̂g/10) )Processing gain [dB] 17.8 14.3 10.0 k = 10*log(3840/bitrate)Required Eb/(No+Io) [dB] 2.0 1.5 1.0 m
Receiver sensitivity [dBm] -115.9 -112.9 -109.2 n = m-k+j + 10*log10(3840000)SHO Gain [dB], multi-cell 2.0 2.0 2.0 tRX Antenna Gain [dB] 20.5 20.5 20.5 oCable loss of BS in UL / Body loss of MS in DL [dB] 2.0 2.0 2.0 pTPC headroom [dB] 4.0 4.0 4.0 qMax. path loss [dB] 156.4 153.4 149.6 r = d - n + o - p + q +t
Coverage Probability [%] 80 80 80Log Normal Fade Constant [dB] 12 12 12Propagatiom odel exponent 3.38 3.38 3.38Log Normal Fade Margin [dB] 4.4 4.4 4.4 sBS antenna heigh 40 40 40MS antenna height 1.5 1.5 1.5Area type correction 0 0 0 UrbanIndoor Loss [dB] 15.0 15.0 15.0 u
2G&3G LINK BUDGET2G&3G LINK BUDGETWCDMA Link Budget GSM1800 Link Budget144 kbps NRT Packet data 10 % FER target, load 50 % Uplink Uplink
Max. TX Power per channel [W] 0.25 1As above in dBm 24.0 30.0 aTX Antenna Gain [dB] 0.0 0.0 bBody loss of MS in UL / Cable loss of BS in DL [dB] 0.0 0.0 cTransmit EIRP per channel [dBm] 24.0 30.0 d = a + b - c
Thermal Noise Density [dBm/Hz] -174.0 -174.0 eReceiver Noise Figure [dB] 5.0 5.7 fReceiver Noise Density No [dBm/Hz] -169.0 g = e + fRise Over themal (Io+No)/No [dB] 3.0 h=10log(1-load)Total interference density : Io = (1-a) Ior + Ioc [dBm/Hz] -169.0 i = 10*log( 10 (̂(h+g)/10)-10 (̂g/10) )Total effective noise + interference density : Io + No [dBm/Hz] -166.0 j = 10*log( 10 (̂i/10)+10 (̂g/10) )Processing gain [dB] 14.3 k = 10*log(3840/144)Required Eb/(No+Io) [dB] 1.5 8.0 m
Receiver sensitivity [dBm] -112.9 -106.0SHO Gain [dB], multi-cell 2.0 0.0 tRX Antenna Gain [dB] 20.5 20.5 oCable loss of BS in UL / Body loss of MS in DL [dB] 2.0 2.0 pTPC headroom [dB] 4.0 0.0 qMax. path loss [dB] 153.4 154.5 r = d - n + o - p + q +t
Coverage Probability [%] 80 80Log Normal Fade Constant [dB] 12 12Propagatiom odel exponent 3.38 3.38Log Normal Fade Margin [dB] 4.4 4.4BS antenna heigh 40 40MS antenna height 1.5 1.5Area type correction 0 0Indoor Loss [dB] 15.0 15.0
Io = Total spectral interference plus noise densityIo= No+Ioc+Ii= No+Ioc+(n-1)vS/W
W WCDMA bandwidthn Number of active callsNo Thermal noise spectral density at the input to the receiver LNA [w/Hz]v voice activity factor (e.g. v = 0.5)C/I Signal (carrier) to noise and interference ratio
• Energy per bit of data
Rb The data rate (bit rate) (e.g. 8 kbps) Figure of merit of a digital receiver (e.g. 5 dB for WCDMA)
Uplink Load Factor and Pole CapacityUplink Load Factor and Pole Capacity
iRWNoErx
k
kbNk
k
1/
/_1
N : Number of "active" radio links per cell (DTX factor)rx_Eb/Nok : Received Eb/No of radio link k at the BSW / Rk : Processing gain at the given bit ratei : Other cell to own cell interference ratio seen by the BS
Loss in link budget due to load= Interference margin (IM)= -10*log10(1-)
MS_TxP = Transmit power per radio link needed for coverage + Loss
Downlink Load Factor and Pole CapacityDownlink Load Factor and Pole Capacity
kkk
kbNk
k
iRWNoEtx
1/
/_1
N : Number of "active" radio links per cell (inc. DTX factor and SHO)tx_Eb/Nok : Transmit Eb/No of the radio link arrived at MS kW / Rk : Processing gain at the given bit ratei k : Other cell to own received BS power ratio seen by MSk, k : Orthogonality factor in Downlink seen by MS k (*
(* Due to multipath propagation, DL orthogonality is no longer maintained when BS signal arrives MS. 1- represents the amount of intra-cell interference seen by the MS receiver
0
5
10
15
20
25
0 0,2 0,4 0,6 0,8 1
Load factor
BS
tran
smit
pow
er r
ise
(dB
)BS transmit power rise due to load= -10*log10(1-)
BS_TxP = Transmit power for coverage of all radio links + power rise BS_TxP when 1 !!!
CDMA radio access technology CDMA radio access technology
Freq. 1
Freq. 1
Code A
Code B
Code
C
BS1
BS2
Code D
Code E
• Users are separated by codes (code channels), not by frequency or time (in some capacity/hierarchical cell structure cases, also different carrier frequencies may be used).
• signals of other users are seen as noise-like interference
• CDMA system is an interference limited system which averages the interference (ref. to GSM which is a frequency limited system)
CDMA radio access technology: CDMA radio access technology: spreading/despreadingspreading/despreading
• Two main spread spectrum methods: Direct Sequence (DS) and Frequency Hopping (FH). DS used in ARIB/ETSI systems.
• In DS spreading the user signal spreading (modulation) is done with spreading sequencies (codes) having much higher bandwith than the user signal (processing gain = W/R, where R = data rate, W = spread bandwith)
• codes are unique for each channel
• transmitting and receiving sides have the same code with the same phase. The code to be used is determined by the transmitting side and the receiving side acquires the code from the transmited signal (code acquisition)
CDMA radio access technology: CDMA radio access technology: Power Control Power Control
• power control on the uplink is the key to the WCDMA capacity, downlink is less critical
• the power of separate users is controlled in such a way that received power from all users are roughly equal and the total power in the system is minimal==> users can occupy the same carrier and the interference averaging takes place
• if the power control is incomplete, there will be severe problems, refer to the so called near-far-problem (see figure below). Normally the uplink power control range is 70-90 dB, the receiver can handle power differencies not exceeding the spreading ratio (normally 6..20 dB).
S
BS
MS1
MS2
If the power of MS1 is not properly controlled it will jam the weaker signal of MS2
Detailed Planning means CDMA Analysis Detailed Planning means CDMA Analysis • 2G detailed planning is coverage and frequency planning +interference analysis
• 3G detailed planning is calculation of the UL/DL best servers, UL/DL SHO areas, BCCH C/Is, cell loading, SHO overhead and SHO probabilities