CT0173en.001( Overview).ppt
Transcript of CT0173en.001( Overview).ppt
1 © NOKIA CTDF 0173 / 20.9.1999 / Sanjiva Sabanayagam
Welcome to
FlexiHopper Course
2 © NOKIA CTDF 0173 / 20.9.1999 / Sanjiva Sabanayagam
OverviewOverview
• Power supply unit
• Modem board includes:
• microprocessor environment
• digital signal processing (RATS ASIC and two CIAD ASICs)
• analog signal processing (TX and RX antialiasing filters)
• analog measurements
• Single cable interface (COBRA)
• AD/DA conversion
• IF unit
• Microwave unit
3 © NOKIA CTDF 0173 / 20.9.1999 / Sanjiva Sabanayagam
FlexiHopper Block Diagram
Indoor Unit
.
.
.
C I
uP 302 x 2
MUX ASICLineInter-face
CICI DC/DC
Pow
Q1/LMP
FlexBusFlexBus
Single-cable
DSP ASIC
uP 302
DC/DC
C I
2M
Outdoor Unit
TX/RX filt.LNA
Duplex
HPA
LO
IQ-MOD
LO Ant
MIX
MWUPLL
AGC+filt.
IF-LO
IQ-demod.
Modem IF-parts MWU
Power/CI
2...16x2M
( Cable Interface)
4 © NOKIA CTDF 0173 / 20.9.1999 / Sanjiva Sabanayagam
Nokia FlexiHopper Outdoor Unit - Mechanical ConstructionOutdoor Unit - Mechanical Construction
5 © NOKIA CTDF 0173 / 20.9.1999 / Sanjiva Sabanayagam
Customer Specs (not guaranteed)Customer Specs (not guaranteed)• Programmable capacities 2x2, 4x2, 8x2 and 16x2
• Modulation method Pii/4-DQPSK
• Input power < 25W
• Flexbus: Single cable for power and data.
• Channel Spacing for 2*16 E1- 28 MHz
FrequencyGHz
IF frequencyMHz
Nominal TXpower/dBm
Treshold2x2Mbittypical/dBm
Treshold4x2Mbittypical/dBm
Treshold8x2Mbittypical/dBm
Treshold16x2Mbittypical/dBm
13 266 19 -90 -87 -84 -81
15 420728644
19 -90 -87 -84 -81
18 1010 16 -90 -87 -84 -81
23 12321008
16 -89 -86 -83 -80
26 1008 16 -89 -86 -83 -80
38 1260 16 -86 -86 -83 -80
6 © NOKIA CTDF 0173 / 20.9.1999 / Sanjiva Sabanayagam
MP
OUTINOUTINOUT INOUTIN
LMP PWR _ + Q1 Q2 FB1FB2
Flexihopper Radio Link Family FeaturesFlexihopper Radio Link Family Features
• Software download• Selectable interleaving (off, 2-depth, 4-depth)• Forward error correction ( FEC)• MTBF estimation 290 000 hours• Fading margin measurement • Temperature range - 40ºC to + 55ºC• Size W x H x D 210mm x 230mm x 80mm - 165mm• Weight without antenna and alignment app. 3.5 to 4.5 kg• ALCQ or adaptive level control with quality measure• Controlled by Node manager, Q1 or service terminal emulator
7 © NOKIA CTDF 0173 / 20.9.1999 / Sanjiva Sabanayagam
FEC ( FEC ( Forward Error CorrectionForward Error Correction) & Interleving ) & Interleving • Nokia FlexiHopper radios use forward error correction (FEC) and interleaving to
improve signal quality.
• The FEC is continuously on and the interleaving is selectable between off, 2-depth, and 4-depth modes.
• The forward error correction uses Reed-Solomon coding (RS(63,59)). The code uses 4 redundancy symbols for every 59 data symbols, so the redundancy of the coding is 6.4%. Together with interleaving also errors of burst type can be corrected. Maximum error correction effectiveness is achieved with 4-depth interleaving.
• When the interleaving is in use, transmission delay increases slightly .This is normally not a problem, but in long chains of radio-links the delay cumulates, and it might be necessary to turn the interleaving off. Acceptable delay for a chain of links should be determined in transmission planning stage and the interleaving status set accordingly.
• Recommended " Interleaving to be OFF in Condition"
8 © NOKIA CTDF 0173 / 20.9.1999 / Sanjiva Sabanayagam
Automatic fading margin measurementAutomatic fading margin measurement
• During the commissioning of a microwave radio, it is possible to measure the fading margin of the radio hop.
• Traditionally this has required much work and additional hardware, such as RF (radio frequency) attenuators.
• In Nokia FlexiHopper, the fading margin measurement is automatic and can be started simply by using software.
9 © NOKIA CTDF 0173 / 20.9.1999 / Sanjiva Sabanayagam
ALCQ( ALCQ( Adaptive Level Control with Quality Measure)Adaptive Level Control with Quality Measure)
• ALCQ is a method for automatic transmit power control. This feature enables the radio transmitter to increase or decrease the transmit power automatically, according to the response received from the other end of the hop. This approach achieves more efficient utilization of radio frequencies than the constant level approach.
• The controlled use of transmit power reduces interference between systems, which in turn allows tighter packing of radio links within the same geographical area or at network star points.
• The maximum transmission power is set with Hopper Manager. When ALCQ is in use, the radio always tries to transmit at minimum power. If the fading increases rapidly (multipath fading), the radio reacts immediately by increasing the power, but not higher than the set maximum value. After the fading conditions resume to normal, the power is gradually decreased. ALCQ also reacts to slow changes in fading conditions by gradually increasing the transmission power.
10 © NOKIA CTDF 0173 / 20.9.1999 / Sanjiva Sabanayagam
Automatic Fading Margin Measurement
STATION 1 STATION 2
CONTROL CONTROL
DUPLEXFILTER
DUPLEXFILTER
TRAN
SMIT
TER
TRAN
SMIT
TER
REC
EIVE
R
REC
EIVE
R
MAIN SIGNAL
CONTROLS
Prx/dBm
Pdet/dBPsig,det
Pthni,detPth,detPni,detPn,det
Pn Pni
Pthn
Pthn
i
Psig
ACTUALFADE MARGIN