radio modem · 2019. 3. 15. · of radio modem equipment •digital line interface: the modem...
TRANSCRIPT
-
For internal circulation of BSNL only
E2-E3
E &WS
Radio MODEM
-
For internal circulation of BSNL only
WELCOME
• This is a presentation for the E2-E3 E&WS
Module for the Topic: Radio MODEM
• Eligibility: Those who have got the Upgradation
to from E2 to E3.
• This presentation is last updated on 26-3-2011.
• You can also visit the Digital library of BSNL to
see this topic.
-
For internal circulation of BSNL only
RADIO MODEM
Long distance connectivity to medium and large
enterprise customers.
It is to establish private networks facilitating
internal communications like office data, inter
office information from various units spread
across the country.
-
For internal circulation of BSNL only
Limitations of legacy L/L
Local leads are more suitable for speed below
2Mbps.
Copper has speed and distance limitations.
Laying of OFC is not possible.
-
For internal circulation of BSNL only
Features of RADIO MODEMS
These links work on the wireless principle
based on line of sight operation.
It comprises of Transmitter-Receiver on both
sides with necessary interface for feeding in &
out.
This system uses free band (2GHz).
These systems are low cost.
-
For internal circulation of BSNL only
Features contd…
Data transmission is in the form of Ethernet on the
system.
Interface for interconnection: V.35 to Ethernet
convertors
Data speeds: Upto 4MBPS (supports speeds upto 10
MBPS.)
Distance range: upto 10 kms, but extendable,
depends on LOS and option taken
-
For internal circulation of BSNL only
Features contd…
Antenna height: a. BSNL End: Either exchange or
BTS tower is used to give maximum height as per
need. The needed height is decided by survey
calculations. It also depends on the height of antenna
at customer site. This varies from case to case.
b. Customer end: Roof top or any structure available.
If height needed is more and no structure is available,
a tripod type mast is erected for the antenna. It is
available in lengths upto 20 metres. Normally the
antenna height at customer end varies from 3m to
20m.
-
For internal circulation of BSNL only
FEATURES OF RADIO MODEM
RADWIN MAKE (M/s SM CREATIVE)
FREQU: ISM BAND 2.4 GHz AND 5.8GHz
DATA TRANS: ETHERNET
INTEFACE: V35 TO ETHERNET
SPEED: UPTO 10MBPS (4MBPS AT
PRESENT)
DISTANCE: UPTO 10 KM
ANTENNA HT: ROOF TOP/ 3M TO 20M
POWER: 230V AC
COST: APPROX. 1.5LAKHS
-
For internal circulation of BSNL only
FEATURES contd…
MODULATION: 1. FHSS 2. DSSS
Tx POWER LIMITS: 1 WATT EIRP
PEAK POWER DENSITY: NOT MORE THAN 8 dB
FREQUENCY RANGE: 2400 MHz TO 2483.5 MHz
5725 MHz TO 5825 MHz
5. PROVISION FOR 1+1 S/B MODE
6. ORDER WIRE FACILITY CAN BE PROVIDED.
-
For internal circulation of BSNL only
ADVANTAGES
1.OVERCOMES LIMITATIONS OF COPPER
2.SPEED UPTO SEVERAL MBPS
3.WORKS BEYOND 20KM
4.MORE RELIABLE THAN COPPER
-
For internal circulation of BSNL only
Functional & Technical Requirements
of Radio Modem Equipment
• Data Rates : The modem shall support one or more of
the following data rates.
• i) 64 Kbps
• ii) 128 Kbps
• iii) 256 Kbps
• iv) 512 Kbps
• v) 2048 Kbps (E1)
• vi) 2 *2048 Kbps (2xE1)
• vii) 4 *2048 Kbps (4xE1)
• viii) 8 *2048 Kbps (8xE1)
-
For internal circulation of BSNL only
Functional & Technical Requirements
of Radio Modem Equipment
• Digital Line Interface: The modem interface shall
be either hardware configurable (e.g. DIP
Switches) or software configurable (e.g. AT
commands) to act as Data Communication
Equipment (DCE) or Data Terminal Equipment
(DTE) as per the requirements.
-
For internal circulation of BSNL only
Functional & Technical Requirements of
Radio Modem Equipment
• Digital Interfaces:
• V.35 / V.36 (ISO – 2593) 34 pin physical
connector.
• V.11 (ISO – 4902) 37 pin physical connector
• V.36/V.35/V.II (ISO – 2110) 25 pin physical
connector
• G.703 Co-directional interface at 64 Kbps with
ISO-2110 connector
• G.703 physical interface with ISO 2110
connector with 120 Ohm balanced for 2048
Kbps. ITU-T recommendation G.703
-
For internal circulation of BSNL only
Modulation
The radio modems shall conform to one of the
following modulation:
i) Frequency Hopping Spread Spectrum (FHSS)
ii) Direct Sequence Spread Spectrum (DSSS)
-
For internal circulation of BSNL only
Frequency Hopping Spread
Spectrum (FHSS)
FHSS modulation shall make use of at least 75
well defined, non-overlapping channels of
hopping positions separated by the channel
bandwidth as measured at 20 dB below peak
power.
-
For internal circulation of BSNL only
FHSS
The maximum 20 dB bandwidth of hopping channel is 1
MHz.
The average time of occupancy on any frequency shall
not be greater than 0.4 seconds within a 30 seconds
period.
The system shall hop to channel frequencies that are
selected at the system hopping rate from a pseudo
randomly ordered list of hopping frequencies.
Each frequency must be used equally on the average by
each transmitter. The system receivers shall have shift
frequencies in synchronization with the transmitted
signals.
-
For internal circulation of BSNL only
Direct Sequence Spread Spectrum
(DSSS)
Direct Sequence Spread Spectrum (DSSS)modulation is a form of modulation in which bothdata to be transmitted and known codesequence are combined and used to directlymodulate a carrier.
-
For internal circulation of BSNL only
Transmitter parameter limits
1. Effective radiated power: For FHSS andDSSS : The maximum peak output powershall not exceed 1 watt effective isotropicradiated power (EIRP).2. Peak power density: For DSSS, the peakpower spectral density shall not be greaterthan 8 dBm in any 3 kHz band during anytime interval of continuous transmission. Forthe hybrid system the power densityrequirement shall comply for the directsequence operation with the frequencyhopping turned off.
-
For internal circulation of BSNL only
Processing Gain
The ratio in dB of the signal-to-noise ratio with thesystem spreading code turned off to the signal-to-noise ratio with the system spreading code turnedon.The processing gain represents the improvement tothe received signal-to-noise ratio after filtering to theinformation bandwidth from the spreading /dispreading function.The processing gain of a DSSS shall be at least 10dB.Hybrid systems that employ a combination of bothdirect sequence and frequency hopping modulationtechniques shall achieve a processing gain of atleast 17 dB from the combined techniques.
-
For internal circulation of BSNL only
Frequency range
The frequency range of the radio modem shalllie within one of the following band:i) 2400 MHz to 2483.5 MHz (FL>2400 MHz andFH < 2483.5 MHz)ii) 5725 MHz to 5825 MHz (FL>5725 MHz andFH < 5825 MHz)
-
For internal circulation of BSNL only
Field strength of emissions
(Specified at a distance of 3 meters.)
Fundamental
Frequency
Field Strength
fundamental
(millivolts/meter)
Field Strength of
Harmonics
(microvolts/meter)
2400 – 2483.5 MHz 50 500
5725 – 5825 MHz 50 500
-
For internal circulation of BSNL only
Spurious emissions limits for
receivers
Narrowband
30 MHz – 1000 MHz -57 dBm
Above 1 GHz – 12.75 GHz - 47 dBm
Wideband
30 MHz – 1000 MHz -107 dBm/Hz
Above 1 GHz – 12.75 GHz - 97 dBm/Hz
-
For internal circulation of BSNL only
Alarm Indications
a) Transmit power failure
b) Receive power below threshold
c) Radio sync loss
d) Power up
e) DTE input loss
-
For internal circulation of BSNL only
Diagnostics
i) Local loop back test
ii) Remote loop back test
iii) Loop back to remove end
iv) Receive power level determination
v) Receive power signal quality determination
vi) Quasi random sequence generator
vii) Data output failure
viii) System log capability for alarms and test
results
ix) Local & remote monitoring
-
For internal circulation of BSNL only