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Research Paper Engineering Volume : 3 | Issue : 4 | April 2013 | ISSN - 2249-555X

Control Command for Microwave Link
Acknowledgment and its Troubleshooting Strategy

Keywords Microwave Communication, NEC Microwave, Microwave Acknowledgment and Troubleshooting

Mohd Aamirullah Inamdar Dr. Sayyad Ajij D
Badi Masjid Campus (B.M.C), R.No:-06, HOD of Electronics & Communication, Engineering
Opposite Osmanpura Post Office, Osmanpura, department, MIT College, Beed Bypass Road
Aurangabad-431005. Aurangabad-431028.
ABSTRACT Initially NEC (Name of company) Microwave manufacturing, Japan is introduced briefly and then various ac-
knowledgments and there different troubleshooting methods. The flow chart to reduce the time of doing trou-
bleshooting is explain. The main objective is to reduce the call drop of TATA DOCOMO and to overcome the drop if occur
within short duration of time. There exists limited literature on NEC microwave, especially with regard to acknowledgments
and troubleshooting. The working of NEC microwave, classification & tools on the basis of the NEC equipment used in TATA
DOCOMO & flow chart to reduced the time is described. According to different types they produce different acknowledgment
and depending upon the acknowledgment the troubleshooting strategy changes.

1. INTRODUCTION: more useful for TATA. The following numbers of operators
Today wireless technology is used in many applications well are using NEC
integrated into our everyday life. Planning a good, stable and
reliable microwave network can be quite challenging. Careful Ø TATA DOCOMO
planning and detailed analysis is required for a microwave Ø Reliance
radio system before the equipment can be installed. A poorly Ø Idea
designed path can result in periodic system outages, result- Ø Airtel
ing in increased system latency, decreased throughput, or Ø Aircel
worst case, a complete failure of the system. It is generally
agreed that a microwave signal is a signal whose fundamen- Only Vodafone and BSNL is not using this equipment they
tal frequency is between 300 MHz and 300 GHz [1, 2]. In are using NOKIA, but it will be helpful for NOKIA employee
terms of wavelength, a microwave signal has a wavelength also for their troubleshooting method [5].
between 0.1 cm and 100 cm A the waveguide is a hollow
mechanical structure that permits propagation of microwave
signals from one point to another with the least possible loss.
Most commonly used waveguides are those having a rec-
tangular form. There are, however, a variety of rectangular
waveguides, each being identified according to its internal
dimensions. Each type of waveguide allows microwave prop-
agation within a particular frequency band [3]. Discussing all
the acknowledgment present in working link of NEC micro-
wave and there trouble shooting methods. Figure 3.1 NEC microwave communication system

2. CLASSIFICATION OF NEC MICROWAVE:
1. SDH(Synchronous Digital Hierarchy)
2. PDH (Plesuchronous Digital Hierarchy)

SDH: Pasolink+ STM1, Pasolink Neoi
PDH: Pasolink CPV, Pasolink V4s

3. WORKING PRINCIPLE:
Fig 3.1 shows the Transmitter converts the source message
into an electrical signal. The Transmitter is basically respon-
sible for encoding the message and then this encoded mes-
sage is multiplied by carrier frequency i.e. modulate the
signal and then over the channel. At the receive end, the
receiver demodulate the received signal and decode it and
generate the original message. Minimal distortion at the re-
ceiver end is referred as a good communication property [4].
Fig.3.2 is the general flow chart, which can be used for any
equipment (Other then NEC) & for any operator (Other then
TATA), the main aim of this flow chart is to reduce the call
drops of any operators, and if drop occurs how to overcome Figure 3.2 Flow chart of trouble shooting Method.
the drop within very small time spectrum. First stage (Start-A)
are written to avoid the call drops, from second stage (A-End) 4. TOOLS:
if call drop occurs how to overcome that drop is mention, The following tools are used in NEC Microwave
because many operators are using NEC equipment In mi-
crowave that’s why it will be helpful to that operators, near 1) Software Tools
about four operators are dependent on TATA that’s why it is 2) Hardware Tools

168 X INDIAN JOURNAL OF APPLIED RESEARCH

if RX level is coming in the range of -99 to -80 dbm at both the end then there is no interference) Ø IDU Ø ODU Acknowledgment 1 [8. building. [6. it is notified that the continuous in. PNMTj is used for observing the alarms is generated.1 In this four alarms is generated. When all this alarm comes together then it means there is a crement in BER creates complications in link. Research Paper Volume : 3 | Issue : 4 | April 2013 | ISSN .when the RX level reduces from their to be considered. out of 1. ODU (Out Door Unit):. DESCRIPTION OF ACKNOWLEDGMENT AND THEIR TROUBLESHOOTING METHODS If Interference:. For example. disconnect pow- 2) Hardware Tools:-Three hardware are used in this. then there is chance that the bit error rate will need TCN-RX LEV-15min:. stage of BER. (To check whether interference exist or not.It act as transmitter which can transmit and receive the microwave signals. power of ODU for microwave link.000 bits transmitted.1 Acknowledgment 1 5. If the medium between the transmitter and receiver is good and the signal to noise ratio is high. LCT for STD is used for commissioning of NEOi IDU and LCT for CPV is used for Troubleshooting commissioning of NEO/ic IDU. in LOF when we transmit signal does not Ø LCT for CPV reach at the receiver end and return to the transmitter. then the bit error rate STM-1(1)(DMR):. er supply at one end and check the RX level at other end and tails are as follows vice versa. RX Level:. details are as follows If misalignment:. one bit was in error. At the starting major chance of power failure at far end. formula: LOF:.when signal to noise ratio decreases it tends to The PNMT is used for the commissioning of Passo+/ increase in BER and due to increase in bit error rate high BER Passo V4 IDU.when any tree. Figure 5. Ø PNMT LOF(Loss Of frame):.we need to change the frequency & frame 1) Description ID at both the end As shown in fig 5.This alarm is generated when receiving level de- The definition of bit error rate can be translated into a simple creases from its limit. Ø EARLY WARNING Ø FRAME ID 2) Description Ø LOF As shown in figure 5. Ø PNMTj etc comes in between the two microwave of single link then Ø LCT for STD this alarm will appear. meaning that.2249-555X 1) Software Tools:.7] limit after 15 mints this alarm will appear. avoid the interference in between the two link) this alarm is ware is used for observing all the sites from the server. a Ø TCN-RX LEV-15min transmission might have a BER of 10 to the minus 6.when there is no transmission through opti- will be very small .9] Ø Antenna IDU (In door Unit):. Early Warning: .It is used for the assigning the frequency. Frame ID: .We need to make the proper alignment at both the ends.Four software’s are used for commis.when there is any frame loss takes place then this alarm BER = number of errors / total number of bits sent will appear.2 In this following alarm are observed Ø HIGH BER Ø RX Level Bit Error Rate (BER) is the percentage of bits that have errors Ø LOF relative to the total number of bits received in a transmission.This alarm is generated due to the increase Troubleshooting in Bit Error Rate (BER). any other radio.000.It is used for the allowing the differ- ent frequency and power for getting the maximum receiving power. the upper band is having more TX frequency then the TX of lower and the RX of upper is the TX of lower and vice versa. The PNMSj is used for the When all this alarm comes together then it means there is a observation of all the types of NEC microwave from the major chance of interference or misalignment server. Ø STM-1(1)(DMR) usually expressed as ten to a negative power. It is of two types upper band & lower band.possibly insignificant and having no no. ticeable effect on the overall system However if noise can be detected. it generates early warning alarm and a incre- ment of BER results in following alarms The power failure may occurs due to following reasons Ø Low BER Ø MCB Trip Ø High BER Ø NO Power Supply Ø DEM Alarm Ø IDU Faulty INDIAN JOURNAL OF APPLIED RESEARCH X 169 . the de. It is also used for observ- ing the alarms in working Link. Antenna:. of NEOi/Neo/ic in working link. Ø PNMSj High BER:. two sites of single link. cal port then this alarm will appear.(It is the application which is inserted by NEC to sioning of different types of NEC microwave and one soft. The generated when there is mismatch of frame ID between the details are as follows.

Sanjeeva Gupta. Luis.Make the arrangement of power supply If IDU faulty:. Md. | 6. 1999. Telecom Regulatory Authority of India. Prentice. F. “Analysis And Planning Microwave Link To Established Efficient Wireless Communications”. | 3. 1957. “Wireless Communications & Networks”. September 2009. | 9.2249-555X If MCB is Trip:.2005 | 8. Abdullah Jr. May 2010. Research Paper Volume : 3 | Issue : 4 | April 2013 | ISSN . Japan. April 2003. William Stalling. by providing the proper trouble- shooting command action with respective to the feedback error signal. Rakib Al Mahmud. Carlos Evangelista. EM Clarity White Paper. H. we have reduced the microwave acknowledgement with the particular alarm at particular frame. 170 X INDIAN JOURNAL OF APPLIED RESEARCH . J. | 2. Deon Reynders [Online Book]. Molinaro. Website of NEC Corporation. Microwave Engineering.Then either change the MCB or repair the Acknowledgment 2 MCB If No power Supply:.Hall.please check the power card if not working change the power card and if it may creating problem the changed the complete IDU. L Bermudez. | 5. Figure 5. Conclusion By the sanctity of caller and callee voice information. | 4. Due to minimization of microwave error signal we can improve the quality of microwave signal and reducing the call dropping between caller and callee. “Tools For Microwave Radio Communications System Design”. Practical telecommunications and wireless communications for business AvEdwin Wright. “Basic Path Considerations for A Microwave Link”. Paulo Carvalho. .2 Acknowledgment 2 REFERENCE 1. “Fundamentals of Radio Link Engineering”. 2nd ed. Frank Jimene. McGraw-Hill | 7.