Sunday, November 18, 2007

Network Components Of GSM



The Several Network Components Of GSM are Mobile Station (MS), Base Station Subsystem (BSS) & Network Switching Subsystem (NSS).

The MS is composed by:
  • ME - Mobile Equipment, which is identified by the International Mobile Equipment Identity (IMEI).
  • SIM - Subscriber Identity Module, which contains the subscriber-specified data to access GSM Network, except in emergency calls.
The Base Station Subsytem is composed by :
  • BTS/BS - Base Transceiver Station/Base Station, which is responsible for the communication to and from MSs via air interface. The MS communicates with mobile station using a radio channel to a BTS.
  • BSC - Base Station Controller, which is used to monitor and control several base stations, frequency administration, control of BTSs, exchange functions. It is also responsible for all the radio interface management, channel allocation & release, handover management.
The Network Switching System (NSS) is the main component of the public mobile network GSM and is used for switching, mobility management, interconnection to other networks and system control.

The several components of the NSS are :
  • MSC - Mobile Switching Centre: controls all connections via a separated network to/from a mobile terminal within the domain of the MSC - several BSC can belong to a MSC.
  • HLR - Home Location Register: central master database containing user data (Subscriber ID - IMSI & MSISDN), permanent and semi-permanent data of all subscribers assigned to the HLR.
  • VLR - Visitor Location Register: local database for a subset of user data, including data about all users currently in the domain (each VLR is associated exactly to one MSC) of the VLR.
  • EIR – Equipment Identity Register: registers GSM mobile stations and user rights, stolen or malfunctioning mobile stations can be locked and sometimes even localized.
  • OMC - Operation and Maintenance Center: different control capabilities for the radio subsystem and the network subsystem.

Indikasi Hati Yang Mencintai Dunia - For Moslem

Ada beberapa indikasi hati yang menandakan kita lebih mencintai Dunia daripada Akhirat :
  1. Beribadah kepada Allah dianggap sebagai beban dan kewajiban.
  2. Menuntut ilmu syariat dianggap sebagai kegiatan yang menyibukkan.
  3. Bersedekah dan beramal dianggap sebagai pengeluaran.
  4. Bangun pada seperti akhir malam dirasa sebagai kesulitan.
  5. Membayar zakat dirasakan sebagai penguras kekayaan.
  6. Harta dan kekayaan dianggap sebagai milik pribadi.
  7. Bekerja setiap hari dianggap sebagai upaya untuk mencari kehidupan.
Mudah-mudahan kita menjadi orang-orang dalam kriteria diatas.
Dari Buku 3T (Tobat, Tasbih, Tahajjud)

Tuesday, November 6, 2007

Iron & Velvet Leadership

Ketegasan dalam memimpin yang dibungkus dengan kelembutan dapat diibaratkan sebaga iron grip in velvet gloves-tangan besi di dalam sarung tangan beludru. Kepalanya adalah kepalan besi, tetapi bungkusnya beludru yang lembut. Ini adalah bentuk kepimpinan yang saya anggap canggih, suatu bentuk kepimpinan tingkat tinggi, yang dikantor kami sering disebut I-V leadership.
Iron and velvet leadership berarti pemimpin dituntut untuk tampil tegas, keras, dan tidak mudah dibengkokkan. Namun sebenarnya seorang pemimpin diharapkan untuk tampil selembut beludru yang terasa sangat halus saat diusapkan ke wajah kita, sehingga orang yang dipimpinnya mau mendekat, merasa nyaman, namun sadar bahwa pemimpinnya tegas. Ia juga mempunyai kemauan, bijak, tidak bisa ditawar, walaupun penampilan luarnya sangat lembut.
Di jaman dimana demokrasi dijunjung tinggi dan sensitif terhadap ham, sikap tegas yang diungkapkan dengan cara yang keras tidak akan mengundang simpati. Ia bahkan menimbulkan pembangkangan dan perlawanan sehingga kontraroduktif untuk saat ini.
Berbeda dengan I-V Leader: seorang pemimpin yang kuat, tetapi tidak kasar, berbudi halus, tapi tidak lemah. Berani terbuka dan terus terang, tetapi tidak berarti kejam tanpa perasaan. Banyak pertimbangan, tetapi tidak lamban. Rendah hati, tetapi tidak rendah diri. Berpenampilan elegan, tetapi seperti syair lagu anak-anak "Baik hati dan tidak sombong".
Ini adalah kepimpinan yang telah diuji oleh jaman: Tak lekang oleh panas, tak lapuk oleh hujan. Tinggal bagaimana rektualisasinya dalam kehidupan masa kini.
Oleh A. B. Susanto untuk Garuda Magazine

Friday, November 2, 2007

What Is Cell Breathing In CDMA System ?

  • In CDMA systems all mobile can use the same carrier frequency at the same time.
  • This means that there will be interference between user in the same cell and neighboring cells.
  • The CDMA spreading and despreading processes allow this interference to be suppressed to some degree.
  • The level of suppression is termed the system processing gain.
  • The processing gain can be defined as
  • The processing gain will vary according to the service.
  • As the loading within a cell is increased, The BS receiver noise floor appears to rise.
  • The mobile must transmit additional power to overcome the increased interference
  • As a result the maximum path loss can be tolerated within a cell is decreased and cell effectively shrinks

3G Overview

1. 3G Systems
3G Systems are intended to provide a global mobility with wide range of services including telephony, paging, messaging, Internet and broadband data. International Telecommunication Union (ITU) started the process of defining the standard for third generation systems, referred to as International Mobile Telecommunications 2000 (IMT-2000). In Europe European Telecommunications Standards Institute (ETSI) was responsible of UMTS standardisation process. In 1998 Third Generation Partnership Project (3GPP) was formed to continue the technical specification work. 3GPP has five main UMTS standardisation areas: Radio Access Network, Core Network, Terminals, Services and System Aspects and GERAN.

3GPP Radio Access group is responsible of:
• Radio Layer 1, 2 and 3 RR specification
• Iub, Iur and Iu Interfaces
• UTRAN Operation and Maintenance requirements
• BTS radio performance specification
• Conformance test specification for testing of radio aspects of base stations
• Specifications for radio performance aspects from the system point of view

3GPP Core Network group is responsible of:
• Mobility management, call connection control signalling between the user equipment and the core network.
• Core network signalling between the core network nodes.
• Definition of interworking functions between the core network and external networks.
• Packet related issues.
• Core network aspects of the lu interface and Operation and Maintenance requirements

3GPP Terminal group is responsible of:
• Service capability protocols
• Messaging
• Services end-to-end interworking
• USIM to Mobile Terminal interface
• Model/framework for terminal interfaces and services (application) execution
• Conformance test specifications of terminals, including radio aspects

3GPP Services and System Aspects group is responsible of:
• Definition of services and feature requirements.
• Development of service capabilities and service architecture for cellular, fixed and cordless applications.
• Charging and Accounting
• Network Management and Security Aspects
• Definition, evolution, and maintenance of overall architecture.


Third Generation Partnership Project 2 (3GPP) was formed for technical development of cdma2000 technology which is a member of IMT-2000 family.
In February 1992 World Radio Conference allocated frequencies for UMTS use. Frequencies 1885 - 2025 and 2110 - 2200 MHz were identified for IMT-2000 use. See the UMTS Frequency page for more details. All 3G standards are still under constant development. In 1999 ETSI Standardisation finished for UMTS Phase 1 (Release '99, version 3) and next release is due December 2001. UMTS History page has a list of all major 3G and UMTS milestones. Most of the European countries and some countries round the world have already issued UMTS licenses either by beauty contest or auctions.


2. UMTS Services

UMTS offers teleservices (like speech or SMS) and bearer services, which provide the capability for information transfer between access points. It is possible to negotiate and renegotiate the characteristics of a bearer service at session or connection establishment and during ongoing session or connection. Both connection oriented and connectionless services are offered for Point-to-Point and Point-to-Multipoint communication.

Bearer services have different QoS parameters for maximum transfer delay, delay variation and bit error rate. Offered data rate targets are:
• 144 kbits/s satellite and rural outdoor
• 384 kbits/s urban outdoor
• 2048 kbits/s indoor and low range outdoor

UMTS network services have different QoS classes for four types of traffic:
• Conversational class (voice, video telephony, video gaming)
• Streaming class (multimedia, video on demand, webcast)
• Interactive class (web browsing, network gaming, database access)
• Background class (email, SMS, downloading)

UMTS will also have a Virtual Home Environment (VHE). It is a concept for personal service environment portability across network boundaries and between terminals. Personal service environment means that users are consistently presented with the same personalised features, User Interface customisation and services in whatever network or terminal, wherever the user may be located. UMTS also has improved network security and location based services.



3. UMTS Architecture

A UMTS network consist of three interacting domains; Core Network (CN), UMTS Terrestrial Radio Access Network (UTRAN) and User Equipment (UE). The main function of the core network is to provide switching, routing and transit for user traffic. Core network also contains the databases and network management functions.

The basic Core Network architecture for UMTS is based on GSM network with GPRS. All equipment has to be modified for UMTS operation and services. The UTRAN provides the air interface access method for User Equipment. Base Station is referred as Node-B and control equipment for Node-B's is called Radio Network Controller (RNC). UMTS system page has an example, how UMTS network could be build.

It is necessary for a network to know the approximate location in order to be able to page user equipment. Here is the list of system areas from largest to smallest.
• UMTS systems (including satellite)
• Public Land Mobile Network (PLMN)
• MSC/VLR or SGSN
• Location Area
• Routing Area (PS domain)
• UTRAN Registration Area (PS domain)
• Cell
• Sub cell


4. Core Network

The Core Network is divided in circuit switched and packet switched domains. Some of the circuit switched elements are Mobile services Switching Centre (MSC), Visitor location register (VLR) and Gateway MSC. Packet switched elements are Serving GPRS Support Node (SGSN) and Gateway GPRS Support Node (GGSN). Some network elements, like EIR, HLR, VLR and AUC are shared by both domains.

The Asynchronous Transfer Mode (ATM) is defined for UMTS core transmission. ATM Adaptation Layer type 2 (AAL2) handles circuit switched connection and packet connection protocol AAL5 is designed for data delivery.

The architecture of the Core Network may change when new services and features are introduced. Number Portability DataBase (NPDB) will be used to enable user to change the network while keeping their old phone number. Gateway Location Register (GLR) may be used to optimise the subscriber handling between network boundaries. MSC, VLR and SGSN can merge to become a UMTS MSC.


5. Radio Access

Wide band CDMA technology was selected to for UTRAN air interface. UMTS WCDMA is a Direct Sequence CDMA system where user data is multiplied with quasi-random bits derived from WCDMA Spreading codes. In UMTS, in addition to channelisation, Codes are used for synchronisation and scrambling. WCDMA has two basic modes of operation: Frequency Division Duplex (FDD) and Time Division Duplex (TDD). UTRAN interfaces are shown on UMTS Network page.

The functions of Node-B are:
• Air interface Transmission / Reception
• Modulation / Demodulation
• CDMA Physical Channel coding
• Micro Diversity
• Error Handing
• Closed loop power control

The functions of RNC are:
• Radio Resource Control
• Admission Control
• Channel Allocation
• Power Control Settings
• Handover Control
• Macro Diversity
• Ciphering
• Segmentation / Reassembly
• Broadcast Signalling
• Open Loop Power Control


6. User Equipment

The UMTS standard does not restrict the functionality of the User Equipment in any way. Terminals work as an air interface counter part for Node-B and have many different types of identities. Most of these UMTS identity types are taken directly from GSM specifications.
• International Mobile Subscriber Identity (IMSI)
• Temporary Mobile Subscriber Identity (TMSI)
• Packet Temporary Mobile Subscriber Identity (P-TMSI)
• Temporary Logical Link Identity (TLLI)
• Mobile station ISDN (MSISDN)
• International Mobile Station Equipment Identity (IMEI)
• International Mobile Station Equipment Identity and Software Number (IMEISV)

UMTS mobile station can operate in one of three modes of operation:
• PS/CS mode of operation: The MS is attached to both the PS domain and CS domain, and the MS is capable of simultaneously operating PS services and CS services.
• PS mode of operation: The MS is attached to the PS domain only and may only operate services of the PS domain. However, this does not prevent CS-like services to be offered over the PS domain (like VoIP).
• CS mode of operation: The MS is attached to the CS domain only and may only operate services of the CS domain.

UMTS IC card has same physical characteristics as GSM SIM card. It has several functions:
• Support of one User Service Identity Module (USIM) application (optionally more that one)
• Support of one or more user profile on the USIM
• Update USIM specific information over the air
• Security functions
• User authentication
• Optional inclusion of payment methods
• Optional secure downloading of new applications

Communication Models


Exchange of speech or data between parties:
  • Source: generates data, personal computer or telephone
  • Transmitter: transforms & encodes the information into electromagnetic signals
  • Transmission system: a pair of wires or a complex world-wide network
  • Receiver: accepts signal from transmission system and converts it into a form that can be handled by the destination device
  • Destination: takes and uses the incoming data from the receiver

Network Types In Telecommunication

Network Types :

  • Circuit switched network. At start of complete message transaction (telephone call) a route through the network is identified and held for the entire duration of the call
  • Packet switched network. Routes small ‘chunks’ (packets) of the message down the best route at that time – least noisy, least congested…

Advantages Of Packet networks
  • Optimise route on packet by packet basis
  • Attractive for ensuring best use of the network – optimum traffic throughput
  • Signalling overhead to ensure the packets arrive in the correct sequence at the receiver when they have travelled via different paths
Packet switched good for data - Internet

Circuit switched more attractive for voice

Telecommunication - The Death of Distance

  • Distance will no longer determine the cost of communicating electronically – work around the clock
  • Location will no longer be key to business decisions – rebirth of cities
  • Size will no longer be so relevant
  • More customized content
  • Communities of practice – horizontal bonds
  • Inversion of home and office

Bill Gates - Insights to anybody starting out…

  • life isn’t fair – get used to it
  • the World doesn’t care about your self esteem; it expects you to accomplish something before feeling good about yourself
  • you won’t make $60,000 a year right out of school, or be a vice-president with a car phone. You have to earn it!
  • think your teacher’s tough? wait till you have a boss – he owns the company!
  • flipping burgers isn’t beneath you; your grandparents called it opportunity!
  • your parents weren’t always boring; it came from feeding you, washing your clothes and paying your bills. So before you save the rain forest from the ‘parasites’ of your parents generation, try delousing your own wardrobe!
  • some schools may have abolished winners and losers but life hasn’t!They may have eradicated ‘fail grades’ and given you as long as you want to get the right answer. This bears no resemblance to reality!
  • life isn’t divided into terms; you don’t get summers off. Employers aren’t interested in helping you ‘find yourself’; you do that on your own time
  • unlike television, real people actually have to leave the coffee shop and go to work!
  • be kind to nerds – chances are you’ll end up working for one!

Mencari Pekerjaan Engineer Telecom & IT di Overseas

Bagi yang rekan-rekan yang berminat untuk mencari Pekerjaan di bidang Telecom & IT bisa mengunjungi http://telecom-career.blogspot.com/ atau bergabung di mailing list parakontel@googlegroups.com .

Ada beberapa proses sebelum kerja di overseas sebagai Engineer Telecom :
  1. Perbaikan Bahasa Inggris, tapi tidak perlu yang terlalu perfect.
  2. Lihat agent-agent yang menawarkan pekerjaan dan kirimkan CV anda ke agent tersebut. Untuk info pekerjaan bisa mengunjungi alamat diatas.
  3. Biasanya kalau mereka berminat maka akan menghubungi kita untuk melakukan interview.
  4. Sesudah itu akan ada lagi interview technical dari user yang akan mempekerjakan kita.
  5. Sesudah itu akan ada proses negosiasi gaji & dan proses pembuatan contract letter.
  6. Yang harus diperhatikan adalah pasal-pasal dalam contract letter jangan sampai ada yang merugikan kita.

Demikian sekilas sharing infomasi untuk jadi Engineer Telecom di Overseas dan selamat mencoba semoga sukses.
Posting ini berdasarkan hasil interview dengan sumber-sumber yang sudah berpengalaman di Pekerjaan Overseas.


Puasa Syawal

Syukur Alhamdullilah akhirnya hari ini menjadi hari ke-6 untuk puasa bulan Syawalku. Mudah-mudahan amal puasa yang telah kulakukan dapat diterima oleh Allah Swt.
Sekilas penjelasan mengenai puasa Syawal, mudah-mudahan bisa menjadi referensi bagi kita untuk lebih rajin lagi beribadah.

Puasa Sunnah Syawal Cetak halaman ini Kirim halaman ini ke teman via E-mail
Oleh: Dewan Asatidz
Assalamualaikum wr. wb.


Pak ustadz saya ingin menanyakan tentang dalilnya puasa sunnah syawal, apa pahalanya, waktu dan berapa lamanya. terima kasih atas perhatian dan jawabannya.
Wassalamualiikum Wr. Wb.

Udin

Jawaban:

Assalamu'alaikum wr. wb.

Saudara Udin, tentang puasa Syawwal bisa kita lihat dari sabda Rasululluh saw yang diriwayatkan dari Ayyub r.a. bahwa Rasulullah saw. bersabda: "Barang siapa berpuasa Ramadhan dan meneruskannya dengan puasa enam hari di bulan Syawwal, berarti dia telah berpuasa satu tahun." (HR. Imam Muslim dan Abu Dawud). Dan masih hadits yang sama dengan perawi lain. (HR. Ibn Majah).

Dalam hadits tersebut diterangkan, bahwa pahala orang yang berpuasa Ramadhan dan enam hari di bulan Syawwal sama pahala dengan puasa setahun. Karena satu pahala kebaikan nilainya sama dengan sepuluh kali kebaikan (QS. Al-An' am:160). Jika satu kebaikan dihitung sepuluh pahala, berarti puasa Ramadhan selama satu bulan dihitung sepuluh bulan. Dan puasa enam hari di bulan Syawwal dihitung dua bulan. Jadi total jumlahnya adalah satu tahun.

Sebagian ulama memperbolehkan tidak harus berturut-turut enam hari, namun pahalanya sama dengan yang melaksanakannya secara langsung setelah Hari Raya. Puasa Syawal juga boleh dilakukan di pertengahan atau di akhir bulan Syawwal.

Hikmah disyari'atkannya puasa enam hari di bulan Syawwal adalah sebagai pengganti puasa Ramadhan yang dikhawatirkan ada yang tidak sah. Demikian juga untuk menjaga agar perut kita tidak lepas kontrol setelah sebulan penuh melaksanakan puasa, kemudian diberi kesempatan luas untuk makan dan minum. Lebih dari itu, puasa Syawal adalah ibadah sunnah yang sangat dianjurkan oleh ajaran agama kita.

Imam Malik menghukumi makruh puasa tersebut. Karena ditakutkan adanya keyakinan dan anggapan bahwa puasa enam hari di bulan Syawwal masuk puasa Ramadhan.

Apabila tidak ada kekhawatiran seperti alasan Imam Malik di atas, maka disunahkan puasa enam hari. Berlomba-lomba untuk memperbanyak pahala.

Demikian semoga membantu. Wallaahu A'lam.
Selamat berpuasa Syawwal.


Muhammad Rafiq Muallimin

Dikutip Dari www.pesantrenvirtual.com