The Subscriber You Have Dialed is not Reachable

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1 I J C International Journal of lectrical, lectronics and Coputer ngineering 1(1): 28-32(2012) The Subscriber You Have Dialed is not Reachable Dr. Anubhuti Khare*, Manish Saxena** and Sonal Dixit** Departent of lectronics and Counication, *University Institute of Technology, Rajeev Gandhi Technical University, Bhopal, (MP), India **Bansal Institute of Science and Technology Bhopal, (MP), India (Recieved 25 March 2012 Accepted 10 April 2012) ISSN No. (Online) : ABSTRACT : In the obile counication the network proble has been becoe a ajor proble due to this the obile subscriber is feeling very uncofortable with it and obile service operators are also facing difficulties to sort out this proble. Here in this article we are concentrating on network proble inside the indoor preises because according to teleco survey 70% obile calls are originating or terinating inside the indoor preises. Keywords: Fetocell, GSM, Micro cells, Network Congestion. I. INTRODUCTION This is the dialogue we listen very frequently in our daily life, whenever we want to ake a call to obile subscriber fro our obile phone or fro basic land line phone. The wireless capacity has doubled every 30 onths since X iproveent fro wider spectru 5X iproveent by dividing the spectru into saller slices 5X iproveent by designing better odulation schees 1600X gain transit distance. Mobile counication eans wireless counication fro any point to any point with full freedo to ove anywhere. This is very practical phenoena that full obility over the earth is very difficult with currently used technologies but geographical wide range is not the reason for being subscribe out of network ost of the tie. The ain proble of current cellular network [7]. The expensive deployent cost of network infrastructure Low signal strength received fro an outdoor BS inside a building According to one Teleco survey 70% calls for obile subscribes are generated fro indoor to the subscriber sitting soewhere inside the indoor preises. Soe studies on wireless usage shows ore than 50% voice calls and ore than 70% data traffic are originated indoor. This survey indicates that we have to concentrate ore on anaging our GSM cells inside the buildings of alls, offices and apartents etc. instead of increasing or relocating the BTSs. and the solution is Fetocell [3, 9]. A fetocell is a sall cellular base station, typically designed for use in a hoe or sall business. It connects to the service provider's network via broadband (such as DSL or cable), current designs typically support 2 to 5 active obile phones in a residential preises, and 8 to 16 active obile phones in enterprise preises. A fetocell allows service providers to extend service coverage indoors, especially where access would otherwise be liited or unavailable [1,3, 6]. Fig.1. Fetocell.

2 Khare, Saxena and Dixit 29 Fig. 2. Fetocell Architecture. F2 F1 Frequency Dedicated to Fetos c y e n u q Fre F2 F1 Macro/Feto Frequency Reuse Territory Macro coverage Feto coverage Fig. 3. RF deployent scenarios for fetocell systes. For a obile operator, the attractions of a fetocell are iproveents to both coverage and capacity, especially indoors. This can reduce both capital expenditure and operating expense. There ay also be opportunity for new services. Consuers benefit fro iproved coverage and potentially better voice quality and battery life. Depending on the carrier they ay also be offered ore attractive tariffs e.g. discounted calls fro hoe. Fetocells are an alternative way to deliver the benefits of fixed obile convergence (FMC). The distinction is that ost FMC architectures require a new (dual ode) handset which works with existing unlicensed spectru hoe/ enterprise wireless access points, while a fetocell based deployent will work with existing handsets but requires installation of a new access point that uses licensed spectru [2, 5]. Many operators have launched fetocell service including Vodafone, AT & T, Sprint Nextel and Verizon. Note that the 3GPP refers to 3G fetocells as Hoe Node Bs (HNBs). Typically the range of a icrocell is less than two kiloeters wide, a picocell is 200 eters or less, and a

3 30 Khare, Saxena and Dixit fetocell is on the order of 10 eters. Although AT & T calls its product, with a range of 40 feet (12 ), a "icrocell". II. FMTOCLLS: WHY NOW? Indoor coverage has been an industry proble for year and vendors have unsuccessfully tried to develop relevant technology solutions for the hoe. Most services to date involved icro or pico base stations and did not really have the price points to support residential users. Alternative approaches tried ost recently involve dual ode devices based on Wi Fi. While technically copelling, these solutions depend on adoption of new (and expensive) handsets. Fig. 4. A typical traffic profile for a 24 hour period. A nuber of factors are coing together to enable fetocell based solutions: (iv) (v) The high adoption of broadband connections allows the service providers to control the IP backhaul to reduce the backhaul costs for additional usage. Advances in ebedded technologies ake it possible to offer a hoe base station at an acceptable price. As 3G adoption increases, indoor coverage becoes a challenge even in otherwise good 2G coverage regions. Operators who have trialed cell site based hoe zone type services have seen the potential to control hoe zones for iproved custoer retention. New low power GSM spectru has enabled new players to participate in obile offerings based on licensed band fetocells. A. Fetocell Architectures There are two broad fetocell architecture approaches within a obile service provider'snetwork. 1. All IP (SIP/IMS): The SIP/IMS based approach integrates the fetocell through a SIP or IMS based network. This approach leverages a SIP based VoIP network for cost effective delivery, while interworking with a cellular core to extend legacy circuit switched services. In this approach, the CP converts cellular signals to SIP and interfaces to a SIP MSC inter working function (IWF) which connects to the SIP (or IMS) network as well as the circuit switched network. 2. Radio Access Network (IP RAN): The IP RAN based approach effectively considers a fetocell an extension into the operator RAN network and ties the fetocell into the circuit switch core at the edge of the network. This typically involves transporting "Iub" essages over IP into a Radio Network Controller (RNC) or a odified RNC/concentrator. (The Iub is the interface used by an RNC to control ultiple Node B's in a UMTS network.) [2] There are three different variants of this approach being pursued by different vendors, however all three of these variants require either the introduction of or ajor odification to network eleents at the RNC layer of the obile core network: Modified RNC: This approach uses existing or odified RNCs to connect to the circuit switched core network. The CP connects to the RNC via Iub over IP. Concentrator: This is siilar to odified RAN in that it connects to the CS core, but it does it through a new 'concentrator' device that interfaces with the CP. The interface is again based on Iub over IP. UMA: This approach incorporates a UMA client into the CP and connects to the core network via a UMA UNC. B. The Benefits of Fetocells Due to the substantial benefits, fetocell technology is causing quite a "buzz" in the industry. ABI Research has forecasted that by 2011 there will be 102 illion users of fetocell products on 32 illion access points worldwide [9]. Fetocell Benefits to nd Users Reduced "in hoe" call charges Iproved indoor coverage Continued use of current handset Reduced battery drain One consolidated bill Multiple users/lines Fig. 5. An exaple of the call rate on a sapled Monday orning.

4 Khare, Saxena and Dixit 31 Landline support Fig. 7. Fetocell Application. (a) Fetocell Benefits to Mobile Operators Iproves coverage Reduces backhaul traffic Provides capacity enhanceents Reduces churn nables triple play Addresses the VoIP threat Stiulates 3G usage Captures terination fees Allows for ultiple users/lines Addresses the fixed obile convergence arket with a highly attractive and efficient solution. There are several types of copeting technology for the fetocell. Here are soe direct copetitors fro the obile network operator. 1. Dual ode Wi Fi phones Many sartphones (such as the iphone, Blackberry and Google Android) have WiFi receivers built in. These autoatically seek out and use WiFi where it is available, often providing a faster, ore responsive data service than the outdoor obile network. This can work well when visiting the sae places (hoe, work, cafe etc.), but often requires entering a password for each new location. Battery consuption is uch higher when using WiFi, resulting in uch shorter battery life than a 3G fetocell [8]. Soe sartphones can also use Voice over IP (VoIP) applications such as Skype, Truphone or Fring to ake voice calls using WiFi. These applications ay not integrate with the phone's built in address book, operate using a different phone nuber or identity or handle voiceail or essages differently when out of WiFi range. Soe operators actively encourage their sartphone custoers to use WiFi where possible. Sprint andate that all their new sartphone odels have WiFi capability, and ATT Wireless provide free access to over 20,000 WiFi hotspots in public areas. This offloads large aounts of data traffic fro their obile network, iproving perforance for those who need it ost. 2. UMA dual ode phones A special type of WiFi capable phone uses the UMA (Unlicenced Mobile Access) standard to operate sealessly with the obile phone syste, effectively extending the sae service over WiFi with the sae phone nuber, text essaging, voiceail and other services. These are already coercially available and offered in the USA by T Mobile (HotSpot@Hoe) and in France by France Teleco/Orange (Unique). France Teleco report

5 32 Khare, Saxena and Dixit good takeup of the service, which ay be partly due to the heavy penetration of WiFi/DSL odes already sold, and the uch larger geographic coverage (and thus potential poor coverage areas) of the country [5]. The syste requires custoers to use a special dual ode GSM/WiFi phone which restricts the choice of phones significantly. The WiFi ode can be used both at hoe and at any T Mobile or France Teleco hotspot when out and about. Calls can be handed over between the hotspot and the acrocellular network. T Mobile allow access fro any WiFi hotspot, even abroad, while France Teleco restrict access to their own hotspots (including doestic ones). Known coercially live services include: (iv) (v) T Mobile, US Orange Unik, France and other countries Teleco Italia Telia Denark Saunalahti, Finland. 3. Iproved icrocellular coverage and capacity If the service provided by the operator is adequate to eet custoers needs, then they ay not feel it necessary to install their own coplex equipent and risk faults and errors. With any users happy to use only voice and text, there is considerable capacity within the existing obile networks except in particularly dense tower blocks or reote rural areas. The real benefit to the user coes where obile data is used, and where the lower costs of providing this via the obile network can be passed back to the end user. 3G technology has a roadap with continuous iproveents, including HSPA+ that could be deployed as a software upgrade to existing 3G networks. However, new handsets would be required to take full advantage of the iproveents [6]. 4. 3G at lower frequencies such as 850Mhz or 900Mhz Part of the reason that 3G does not operate well indoors is that the global frequency allocated is around 2100MHz. Soe countries, notably Australia, have deployed 3G systes at 850MHz (which is close to the 900MHz 2G GSM frequency coonly used). As a result, uch longer distances can be reached in rural areas (claied broadband service of 2Mbit/s at a distance of 120k using an ourdoor antenna), whilst inbuilding penetration is uch iproved in urban areas. 5. LT (Long Ter volution) This is yet another radio interface, based on OFDM (Orthogonal Frequency Division Multiplexing), which is also used by WiMax. Trial equipent is already deonstrating data rates in excess of 100Mbit/s, and standardisation is proceeding quickly. arly uses are likely to be providing broadband data services in rural areas and relieving areas of high data deand. A wide range of handsets is unlikely to becoe available for soe years. Whilst LT fetocell prototype designs exist, it is generally thought that the data perforance of 3G fetocells will be ore than adequate for the next few years. In any cases, the wireline broadband internet connection would be the liiting factor and prevent an LT fetocell fro delivering better perforance than 3G. Instead, LT fetocells have been proposed for use by network operators who want to provide very high data capacity in specific areas [6]. III. CONCLUSION In order to sort out the network proble in obile counication all the obile service operator should concentrate on indoor network on priority basis and the Fetocell is the best option now a days due to its best perforance and connectivity through internet eans no need of connectivity to BSC directly and so any various services which can be provided through Fetocells. IV. ACKNOWLDGMNT Mrs. Anubhuti Khare one of the authors is indebted to Director UIT RGPV Bhopal for giving perission for sending the paper to the journal. Manish Saxena is also thankful to the Chairen, Bansal Instituteof Science & Technology Bhopal for giving perission to send the paper for publication. Last but not least, I would also like to thanks our HOD and colleagues for supporting us. RFRNCS [1] Theodore S. Rappaport "Wireless counications " Second dition Perason ducation pp.58, [2] Vikra Chandrasekkhar, Jeffrey G. Andrews, and Alan Gatherer, "Feotocell Networks: A Survey," I Counication Magazine, Vol. 46, no.9, pp , Sept. (2008). [3] Arne Sionsson, "Frequency Reuse and Intercell Interference Co Ordination in UTRA," Proceedings I Vehicular Technology Conference (VTC), pp , Apr. (2007). [4] Bin Fan, Yu Qian, Kan Zheng and Wenbo Wang, "A Dynaic Resource Allocation Schee Based on Soft Frequency Reuse of OFDMA Systes," Proceedings I International Syposiu on Microwave, Antenna, Propagation and MC Technologies for Wireless Counications, pp. 1 4, Aug. (2007). [5] Seok Ho Won, Hyeong Jun Park, Jaes O. Neel and Jeffrey H. Reed, "Inter Cell Interference Coordination/Avoidance for Frequency Reuse by Resource Scheduling in an OFDM based Cellular Syste," Proceedings I Vehicular Technology Conference (VTC), pp , Oct. (2007). [6] WiMAX Fetocells: A Perspective on Network Architecture, Capacity, and Coverage I Counication Magazine Vol. 46: Issue 10, Oct. (2008). [7] Fetocell Networks: A Survey I Counication Maganize Vol. 46: Issue 9, Sep. (2008). [8] Keenan, J.M. and Motley, A.J., "Radio coverage in buildings," British Telcco Technology, Vol. 8, no. 1, pp , (1990).