wireless local loop

1. Dr IZHAR-UL-HAQ CIIT, Islamabad

2. wireless local loop By Dr.Izhar-ul-Hq ICT, ISLAMABAD Dr IZHAR-UL-HAQ CIIT, Islamabad

3. What is WLL WLL stands for Wireless Local Loop and it is basically the use of radio to provide a telephone connection to the home. It is sometimes called radio in the loop (RITL) or fixed-radio access (FRA). When WLL connects subscribers to the public switched telephone network (PSTN), radio signals are used as a substitute for copper for all or part of the connection between the subscriber and the switch. Included in this is: cordless access systems, proprietary fixed radio access, and fixed cellular systems. Dr IZHAR-UL-HAQ CIIT, Islamabad

4. Basic WLL communication system Dr IZHAR-UL-HAQ CIIT, Islamabad

5. Copper versus Wireless: The Cost of the Last Mile Dr IZHAR-UL-HAQ CIIT, Islamabad

6. Overview • Throughout the world of telecommunications professionals there has been a dramatic rise in interest in the WLL technology. In the late 20th century, industry analysts predicted that the global WLL market would reach millions of subscribers by the year 2000. An article in ‘Red Herring’ magazine in 1997 predicted that, “the WLL market is expected to grow from $563 million in 1996 to at least $6.3 billion in 2002”. Much of this growth is occurring in emerging economies where half the world's population lacks plain old telephone service (POTS). Developing nations like China, India, Brazil, Russia, and Indonesia are looking to WLL technology as an efficient way to deploy POTS for millions of subscribers—without the expense of burying tons of copper wire. Later on in this document the economics of WLL will further be delved into. Dr IZHAR-UL-HAQ CIIT, Islamabad

7. One of the best economic contributions WLL makes in developed economies is that it helps to unlock competition in the local loop, this enables new operators to bypass existing wireline networks to deliver POTS and data access. It will be shown throughout that the question isn't “will the local loop go wireless?”, but, “when and where?”. The aim of this Lecture is to discuss the history and basics of WLL, and look at the impact in Pakistan and the world. It will also examine the markets both past and present, and attempt to judge the future for this technology. Dr IZHAR-UL-HAQ CIIT, Islamabad

8. History of WLL Wireless access first started to become a possibility in the 1950s and 1960s as simple radio technology reduced in price. For some remote communities in isolated parts of the country, the most effective manner of providing communication was to provide a radio, kept in a central part of the community. By the end of the 1970s, communities linked by radio often had dedicated radio links to each house, the links connected into the switch such that they were used in the same manner as normal twisted-pair links. The widespread deployment of the cellular base station into switching sites helped with cost reduction. Similar access using point-to-point microwave links still continues to be widely used today. Dr IZHAR-UL-HAQ CIIT, Islamabad

9. During the reunification of West and East Germany, much funding was put into increasing the teledensity in East Germany. The installation of twisted-pair access throughout would have been a slow process. In the interim, cellular radio was seen to offer a stop-gap measure to provide rapid telecommunications capability. So in East Germany a number of cellular networks, based upon the analog Nordic Mobile Telephone (NMT) standard, were deployed in the 800 MHz frequency range. The key difference was that subscribers had fixed unit mounted to the sides of their houses to increase the signal strength and hence allow the networks to be constructed with larger cells for lower costs. Thus, we see the first WLL network was born. Dr IZHAR-UL-HAQ CIIT, Islamabad

10. Historical Path Early 1950s. Single-channel VHF subscriber equipment was purchased from Motorola, but the maintenance costs were too high as a result of the valve technology used and the power consumption too high. The trial was discontinued and the subscribers were connected by wire Dr IZHAR-UL-HAQ CIIT, Islamabad

11. Mid-1950s. Raytheon was given seed funds to develop 6 GHz band equipment, which would have a better reliability and a lower power consumption. The designers failed to achieve those goals and the system still proved too expensive Dr IZHAR-UL-HAQ CIIT, Islamabad

12. Late 1950s. Some equipment capable of providing mobile service to rural communities was put on trial. Users were prepared to pay a premium for mobile use, but the system still proved to be too expensive in a fixed application for which users were not prepared to pay a premium. Dr IZHAR-UL-HAQ CIIT, Islamabad

13. Early 1960s Systems able to operate on a number of radio channels were developed, eliminating the need for each user to share a specific channel and thus increase capacity. The general lack of channels and high cost, however, made these systems unattractive. Dr IZHAR-UL-HAQ CIIT, Islamabad

14. Early 1970s. A Canadian manufacturer developed equipment operating at 150 MHz that proved successful in serving fixed subscribers on the Island of Lake Superior. The lack of frequencies in the band, however, precluded its widespread use. Dr IZHAR-UL-HAQ CIIT, Islamabad

15. 1970s Late. The radio equipment from several US manufacturers was linked to provide service to isolated Puerto Rican villages. The service was possible only because the geographical location allowed the use of additional channels, providing greater capacity than would have been possible elsewhere. Dr IZHAR-UL-HAQ CIIT, Islamabad

16. Early 1980s. • Communication satellites were examined for rural applications but were rejected as being too expensive. • 1985. Trials of a point-to-multipoint radio system using digital modulation promised sufficient capacity and reliability to make WLL look promising. Dr IZHAR-UL-HAQ CIIT, Islamabad

17. Four different flavours of WLL systems Cellular-based systems consisting of a network of base stations. The older systems are usually based on analogue technology, which is well proven and low-cost, but provides reduced speech quality, limited data capacity and low security. Examples include NMT 450/900, AMPS, TACS, N-AMPS. The newer digital systems offer better spectrum usage and are cost-effective for voice but are less standardised and still provide only limited fax/data throughput. Examples include GSM, DCS1800/PCS1900, IS-136/D-AMPS, IS-95 800/1900. Dr IZHAR-UL-HAQ CIIT, Islamabad

18. Cordless-based systems. These provide efficient spectrum usage in high densities but with limited range, making high infrastructure costs for smaller cell sizes. Examples include DECT, CT-2, PHS. Dr IZHAR-UL-HAQ CIIT, Islamabad

19. Proprietary systems. These are usually custom-designed for the application and provide high quality voice and data services, and other enhanced services. While many of these systems provide superior service to the cordless and digital cellular standards, they must overcome the inertia created by the high installed base of the older technologies. These include FDMA, TDMA, CDMA systems, such as the products made by Qualcomm and Granger. Dr IZHAR-UL-HAQ CIIT, Islamabad

20. Satellite-based systems, as described above, are also proprietary and are mainly focussed on the mobile market, but fixed line access is also envisaged in a few years. These provide global coverage in virtually all environments, but currently have very high usage costs and there are still unresolved domestic control issues. Examples include Iridium and Globalstar. Dr IZHAR-UL-HAQ CIIT, Islamabad

21. WLL encoding • Safety •         Security •         Minimum of errors •         Most efficient data transfer Dr IZHAR-UL-HAQ CIIT, Islamabad

22. Speech encoding In digital radio systems it is necessary to turn voice signals, which analog into a digital data stream. Speech encoding is a highly complex topic and a full treatment is well beyond the bounds of this talk. The simplest speech encoders are essentially analog-to-digital converters. The analog speech waveform is sampled periodically, and the instantaneous voltage level associated with the speech is converted into a digital level. The two main parameters are: how frequently the speech is sampled "sample rate" and how many different bits are used to describe the voltage level. Dr IZHAR-UL-HAQ CIIT, Islamabad

23. Error-correction coding and interleaving Information transmitted via a radio channel is liable to be corrupted. Interference, fading and random noise cause errors to be received, the level of which depends on the severity of the interference. Error correction is widely deployed in mobile radio, where fast fading is almost universally present. It is less critical in WLL, where the LOS path results in less severe problems. Nevertheless it is still necessary, especially for computer data transfer. Error-correction systems work by adding redundancy to the transmitted signal. The receiver checks that the redundant data is as expected; if it is not, the receiver can make error correction decisions. Error-correction methodologies fall into two categories, block coding or convolutional coding. Both are highly involved and mathematical and are beyond the scope of this talk. Dr IZHAR-UL-HAQ CIIT, Islamabad

24. Ciphering Almost all modern radio systems rely on some form of ciphering to provide secure transmission. The use of such security techniques both reassures the user that the conversation cannot be overheard and allows the operator to authenticate the user. Most ciphering schemes are relatively straightforward. The base station and the subscriber unit agree on a "mask" on a call-by-call basis. To the covert listener, who does not know the mask, the data is incomprehensible. Dr IZHAR-UL-HAQ CIIT, Islamabad

25. Multiple access WLL technologies have differed over the years in the multiple access technologies that they use. A decision about which technology to adopt will depend upon the application. Each operator has a given amount of radio spectrum to divide among its users. There are broadly three main ways to do this Dr IZHAR-UL-HAQ CIIT, Islamabad

26. Frequency Division Multiple Access (FDMA), in which the frequency is divided into a number of slots and each user access a particular slot for a length of a call • Time Division Multiple Access (TDMA), in which each user access all the frequency but for only a short period of time • Code Division Multiple Access (CDMA), in which each user access all the frequency for all the time but distinguishes the transmission through the use of a particular code Dr IZHAR-UL-HAQ CIIT, Islamabad

27. CDMA: One of Multi-Access Technology CDMA Time Code User 3 User 2 TDMA All users obtain service channel at the same time and within the same frequency band User 1 Time Frequency User 3 User 2 FDMA User 1 Time Service channels are allocated to different users at different times, for example: GSM User 1 User 2 User 3 Frequency Service Channels are allocated to different users at different bands, for example: TACS system Frequency Dr IZHAR-UL-HAQ CIIT, Islamabad

28. Overview: What is CDMA? • CDMA stands for "Code Division Multiple Access “ • CDMA is a 3G-based technologies and can works in multi frequency band(450MHz, 800MHz, 1900MHz, 2.1G) .CDMA includes a family of standards developed by 3GPP2: CDMA2000 1X, CDMA2000 1xEV-DO and CDMA2000 1xEV-DV. • It is a popular technology and growing rapidly in both mobile and WLL environment Currently, Over 212 Millions subscribers adopt CDMA technologies. Dr IZHAR-UL-HAQ CIIT, Islamabad

29. What is CDMA450?-----Multiple Working Frequency Band 450MHz 800MHz 1900MHz 2100MHz 2.1GHz 800MHz • CDMA450 is a CDMA2000 system deployed in 450 MHz • CDMA450 is the best choice for WLL with best coverage performance • Massive CDMA450 Successful cases both in developing and developed country Dr IZHAR-UL-HAQ CIIT, Islamabad

30. SMSC/MMSC Mobile IN Data Service Platform HLR OMC HA GMSC MSC/VLR PDSN/FA AAA/AN-AAA Internet PSTN Circuit domain Architecture Packet domain Architecture BSC/PCF/IWF Outdoor Macro BTS Indoor Macro BTS SoftSite iSite/SoftSite SoftSite Handset Fixed Terminal CDMA System architecture introduce Dr IZHAR-UL-HAQ CIIT, Islamabad

31. WLL: Wireless Local Loop • Wireless is now accepted as an alternative local loop technology and its use has increased dramatically by incumbents and new entrants throughout the world. • WLL involves the final connection between the existing telecom infrastructure and a subscriber's home by wireless technologies rather than cable • CDMA WLL technology, which is wireless based, is ideally suited for urban regions of Pakistan as well as congested rural areas where it is extremely difficult to lay the cables • CDMA WLL: an affordable alternative for wire line voice and internet access services Dr IZHAR-UL-HAQ CIIT, Islamabad

32. Wireless Local Loop is booming • In low telecom penetration countries, there is tremendous demand for new business and residential telephone service. More and more operators are looking to wireless technologies to rapidly provide thousands of new subscribers with high-quality telephone service at a reasonable price. • Existing landline operators can extend their network with WLL • Cellular operators can capitalize on their current network to deliver residential service with WLL • New service providers can quickly deploy non-traditional WLL solutions to rapidly meet a community's telephony needs • The unique features and benefits of CDMA make it an excellent technology choice for fixed wireless telephone systems. Dr IZHAR-UL-HAQ CIIT, Islamabad

33. What Problems PTCL Meet for Seamless Coverage Last mile access - Trouble in fixed network C.O • High investment • Transmit cable expense • Land rent • Long deployment delays • Can’t meet increasing market • No mobility C.O C.O C.O Dr IZHAR-UL-HAQ CIIT, Islamabad

34. Service provision Difficulty in rural areas Convenient Telecom will stimulate Economy Fact:Low telecom penetration in Rural Area! • Fixed Line: • High investment, Hard for maintenance • Higher Density area is far away from C.O. or ONU • Tough terrain: Mountains, Rivers, Lakes, Deserts, Gobi and Grassland, etc. • Lack of infrastructure: transmission... • Low productiveness • Low population density with broad area • Less traffic per user • Maintenance cost might be higher than revenue • Satellite Transmission: • High cost, unbearable for public （example: Tibet rural service situation） Dr IZHAR-UL-HAQ CIIT, Islamabad

35. BTS1 BTS2 WLL is The Best Solution • Low investment • Transmission in the air, no cable cost • few infrastructure expense • Quick deployment • attract more sub., especially high-end sub. • Flexible network, easy adjustment • Meet the need of increasing market • Wide coverage, attract new sub. • Remote area • Provide limited mobility Dr IZHAR-UL-HAQ CIIT, Islamabad

36. CDMA450 WLL, an Excellent but Affordable Offering • 450MHz has the best radio propagation for broader coverage; Lower frequencies are the key to reducing cost • Especially suitable for broad, low-density coverage, due to long-range propagation ( up to 30 km ) • Excellent ability to provide urban coverage due to good “line of sight” propagation characteristics • CDMA450 system is a cost-effective 3G solution • CDMA2000 1X, up to 153.6kbps data rate ( in average of 80 Kbps ), • CDMA2000 1xEV-DO, up to 2.4 Mbps data rate ( in average of 800 Kbps ) • Lower infrastructure cost results from broad coverage • Low initial investment, then scale capital investment with the subscriber growth • The 450 MHz range has multiple bands available in many countries Dr IZHAR-UL-HAQ CIIT, Islamabad

37. CDMA450: Better choice for Broadband Access • It is particularly significant in rural areas where currently Internet access is slow dial-up; • Remote education, telemedicine, agricultural and industrial support and government services are always accompanied by high data speed internet access requirements; • CDMA450 is prettily suitable for broad coverage with lower cost vs. other expensive data access solutions; • Enjoy roaming and “always on” service; • Excellent feature of urban better coverage, results from the better radio propagation; • Today 153 Kbps peak value of high-speed data service available, in average of around 70 Kbps, and late in EV-DO, provide 2.4 Mbps peak data rates service, in average of 800 Kbps; Dr IZHAR-UL-HAQ CIIT, Islamabad

38. Summary of CDMA WLL Feature • Frequency • multiple choice: 450M, 800M and 1900M • Maturity • widely application, more than 250 M subs over the world • Cost • The lowest cost per sub • broad coverage(30km for 450Mhz) • high integration • high spectral efficiency • Capacity • 1 CDMA frequency bandwidth = 4 time GSM /4 time Analog /20 time DECT /30 time PHS • Service: • max. Data rate 153.6kbps, • Voice service, circuit data service, packet service • Evolution • evolve to 1xEV- DO or 1xEV-DV smoothly Dr IZHAR-UL-HAQ CIIT, Islamabad

39. Cell radius (km) Cell area (km2) 450 48.9 7521 1 850 950 29.4 2712 2.8 26.9 2269 3.3 1800 1900 14.0 618 12.2 Frequency(MHz) Relative Cell Count 13.3 553 13.6 2100 12.0 449 16.2 System Feature: Larger Coverage, Lower Cost k subs 6 CDMA450 conventional coverage CDMA450 extended coverage 5 4 Voice Capacity in 5MHz 3 GSM with high efficiency technology WCDMA2100 2 GSM conventional coverage GSM extended coverage 1 0 1km 10km 30km Coverage 450MHz has the best radio propagation Dr IZHAR-UL-HAQ CIIT, Islamabad

40. System feature: Multiple Transmission Modes • E1/T1 • Optical fiber • HDSL • Microwave • Satellite Satellite BSC/PCF E1/T1 SDH622/ iSiteC HDSL SDH2.5G Softsite Optical fiber Microwave Softsite Dr IZHAR-UL-HAQ CIIT, Islamabad

41. Projected WLL Subscribers by Region Dr IZHAR-UL-HAQ CIIT, Islamabad

42. CDMA: popular technologies in world CDMA surpasses 212 Million global subscribers SOURCE: WWW.CDG.ORG Dr IZHAR-UL-HAQ CIIT, Islamabad

43. subscribers in Asia Pacific and North America Asia Pacific CDMA Subscriber Growth History:December 1997 through June 2004 Percent of total: 41.8% Percent growth:41% by year SOURCE: WWW.CDG.ORG North America CDMA Subscriber Growth History:December 1997 through June 2004 Percent of total:40.3% Percent growth: 18% by year Dr IZHAR-UL-HAQ CIIT, Islamabad

44. CDMA Worldwide Subscriber Growth Analysis: SOURCE: WWW.CDG.ORG One Year Period June 2003 through June 2004and Second Quarter 2004: April, May, June Dr IZHAR-UL-HAQ CIIT, Islamabad

45. CDMA 450 worldwide deployment Dr IZHAR-UL-HAQ CIIT, Islamabad

46. EVOLUTION OF CDMA2000 • IT EMERGED FROM EIA/TIA IS-95 STANDARD • IMPROVED UPON REVERSE LINK • INTRODUCED ADVANCED VOCODING SERVICES • IMPROVED POWER CONTROL FUNCTIONS Dr IZHAR-UL-HAQ CIIT, Islamabad

47. TECHNICAL SUPERIORITY OF CDMA • LINE OF SIGHT IS NOT REQUIRED AS IN HIGHER FREQUENCY SYSTEMS • RANGE OF TRANSMISSION IS HIGHER THAN DECT/PHS SYSTEMS • BETTER COVERAGE, CAPACITY AND HIGHER DATA RATE AVAILABLE COMPARED TO AMPS, GSM ETC • LOWER PRICE COMPARED TO PROPERIETSRY SYSTEMS Dr IZHAR-UL-HAQ CIIT, Islamabad

48. COMPETETIVE ADVANTAGE • GREATER SPECTRAL EFFICIENCY-MORE THAN 35 USERS PER SECTOR PER 1.25MHz • SUPERIOR VOICE QUALITY-13 Kbps QCELP, 8 Kbps QCELP, EVRC, SMV • FEWER DROPPED CALLS-SOFT AND SOFTER HAND-OFF, CELL BREATHING • LOWER TRANSMISSION POWER-LONGER BATTERY LIFE-TIME • HIGHER DATA THROUGHPUT RATES-153 Kbps with release 0, 307.2Kbps with Release A • ENHANCED GLOBAL ROAMING CAPABILITY-MULTI-BAND,MULTI-MODE HANDSETS AVAILABLE • INHERRENT VOICE SECURITY-2^41 LENGTH PN SEQUENCE • DATA INTEGRITY-ADVANCED ENCRYPTION TECHNIQUES Dr IZHAR-UL-HAQ CIIT, Islamabad

49. COVERAGE ADVANTAGE • 450 AND 800 MHz SYSTEMS OFFER MORE COVERAGE • IN TRADITIONAL TDMA SYSTEMS SYNCHRONIZATION BETWEEN BTS AND SUBSCRIBER TERMINAL ARRISE BUT IN CDMA SYSTEMS…….. Dr IZHAR-UL-HAQ CIIT, Islamabad

50. VOICE CAPACITY ADVANTAGES • MORE THAN 45 ERLANGS OF VOICE CAPACITY PER SECTOR PER 1.25MHz CARRIER • 3-5 TIMES MORE CAPACITY THAN THAT OFFERED BY GSM • DOUBLE THAT OF IS-95 Dr IZHAR-UL-HAQ CIIT, Islamabad