An Introduction to Neutral Host Distributed Antenna Systems

An Introduction to Neutral Host Distributed Antenna Systems 99 Pine Street Albany, NY 12207 (518) 434-2288

Table of Contents Introduction 3 Overview of Distributed Antenna Systems (DAS) 4 Benefits of a Neutral Host DAS 6 Improved Coverage and Quality of Service:...6 Increased Capacity:...7 Capital Cost Reduction:...7 Speed to Market for Service Providers:...7 Evaluating Neutral Host Opportunities 8 Site Survey 10 System Design 11 Construction 12 Optimization and Verification 13 Summary 14

Introduction The demand for seamless voice and data coverage is driving wireless infrastructure. The licensed carriers built their networks to standards that provide voice mobility. With the deployment of wide area high speed data technology CDMA2000, 1xEV-DO and EDGE, the carriers have responded to next generation demands for wireless data communication. Users of wireless services expect them to work where they are. It is a challenge for carriers to provide seamless voice and data coverage indoors. The incumbent wireless infrastructure was not designed to provide in-building service. The concrete and steel materials in our cities and office complexes are barriers to macro network RF signal. The integration of optical technology in RF distributed antenna systems (DAS) provides an efficient indoor coverage system for the licensed 800 and 1900 frequency bands, WLAN, WiFi and 800 MHz public safety bandwidths. For an in-building network a single distribution backbone with a multi-band distributed antenna system can accommodate CDMA, TDMA, GSM, iden, LMR, DCS, GPRS and WiFi 802.11x, all in an interference-free environment. An in-building wireless network typically is a series of hubs, repeaters, and multipleband antennae placed within the building to accommodate and extend signals from the wireless carriers. Infrastructure includes a Distributed Antennae System (DAS), an equipment room, cabling and a network operations system, in either an active or passive DAS solution. Active systems use power to transport the RF signal, passive systems do not use power to amplify or convert the RF signal and require only cabling and antennae to operate. Facility size, design, architecture, locations and number of inhabitants determine the network design. Different buildings require different solutions, as such no one vendor or OEM hardware provides a fits-all solution.

Overview of Distributed Antenna Systems (DAS) To overcome the coverage and capacity problems inherent in the unique features of subways, parking garages and other in-building environments that make it difficult to provide quality service for mobile users, special antenna systems are deployed and distributed in-building. A typical DAS system, multiple antennas or transmitting elements that cover smaller zones (up to 20,000 square feet) are strategically distributed throughout the facility and connected back to the low power equipment via longer cables and system interconnections. In contrast, a typical macro wireless network antennas are connected to high power transmitting and receiving equipment via shorter cables arranged to cover large geographical areas (miles) from one antenna location. Macro antenna systems tend to be bigger and higher, while the DAS systems have many smaller antennas located very close to the mobile users. DAS systems can be broken down into two main categories; Active or Passive. Active systems use power to transport RF between the service provider s equipment and all parts of the DAS. These systems are generally used within large enclosures having complex wall systems. Figure 1: Active System Diagram

Passive systems do not use power to amplify or convert the RF signal and require only cabling, connectors and antennas to operate. Many of the smaller less complex locations can be served with passive systems. The size of the venue, complexity, and other factors will determine the type of system required during the design phase of the process. Figure 2: Passive System Diagram

Benefits of a Neutral Host DAS Distributed Antenna Systems that are designed and available for use by multiple service providers are commonly referred to as neutral host systems. If a DAS system is designed and deployed properly, common coverage and capacity benefits to more than one provider via a single distribution backbone can be achieved without a need to add a series of independent systems. Each carrier needs to provide only the head end equipment, via a dedicated base station or a donor antenna/amplifier, to connect their macro network to the DAS system. A donor site is one that is not exclusively used for the DAS system but also provides service to areas outside of the DAS. Neutral Host Distributed Antenna Systems are a reliable and innovative solution to poor coverage inside buildings, large venues requiring capacity, and inconsistent RF environments where it is difficult to improve quality. There are numerous benefits associated with these systems not only for the service providers and the consumers, but also for property owners. Improved Coverage and Quality of Service: Wireless devices often encounter difficulties maintaining a reliable connection inside buildings. Subscribers expect and demand wireless access wherever they are, whether it s on the 75th floor of a Class A office building, or in its underground retail concourse, at a shopping mall, casino, convention center, airport, or even on a college campus. Large buildings made of metal and concrete such as malls, or underground environments like subways and parking garages form RF resistant structures where the penetration losses are too great to maintain a reliable link to the outside macro cell sites. This is true even in mature wireless networks that have a high density of macro sites covering the outside environment. Distributed Antenna Systems eliminate poor wireless reception in these types of environments. As with any in-building solution, the primary benefit of a Neutral Host DAS is improved coverage throughout the interior of a building or venue. In general, installation of a DAS will result in increased coverage, improved call clarity and higher data throughput. The wireless service providers benefit by accomplishing two key revenue objectives; increased customer satisfaction / decreased churn, and increased in-building airtime minutes-of-use. Additionally, the end user will experience fewer blocked, dropped and missed calls. The property owner benefits by having their customers connected longer, resulting in more time spent within the property, and increased tenant and visitor satisfaction.

Increased Capacity: Wireless carriers often have to off-load traffic from large venues during special events or at peak-usage times by installing dedicated base stations, costly and complex cell splitting or re-sectoring the original macro network. All of these procedures lead to increased capital expenditures and in many cases degraded performance in the surrounding macro network. Using a Neutral Host DAS system to provide capacity for large venues allows macro cells to address other network related issues and allows for reduced power levels, reducing interference and increasing bandwidth. Installation of a Neutral Host DAS provides the opportunity for the wireless service providers to off-load call volume from the existing macro-cell network. The DAS replaces the need for additional base stations or tower locations that may only end up being partially utilized to solve the capacity problem, while the other sectors could be redundant wasted capital. In addition, off-loading subscribers from the macro network to the self contained DAS eliminates any re-sectoring or cell splitting of the surrounding macro cells. The net benefit of a DAS system is a less expensive solution with equipment that is more efficiently utilized, is less intrusive and does not disrupt to the surrounding macro network. Capital Cost Reduction: Equipment, labor, and maintenance costs for deploying in-building systems can be expensive and wireless providers find it difficult to justify the ROI for such systems except for the very top tier venues. By utilizing a neutral host model multiple carriers share the cost associated with these installations while improving subscriber satisfaction and ultimately increasing minutes of use on their system. Since the cost associated with providing service to in-building and other underground or RF resistant environments is shared among multiple carriers in a Neutral Host DAS model, the medium and smaller venues are becoming economically feasible. Speed to Market for Service Providers: Faced with an ever-consolidating market, wireless number portability mandates, and customer churn, carriers need to quickly expand and improve network coverage based on subscriber demand. Well designed Neutral Host DAS networks are an efficient resource for wireless service providers attempting to satisfy the needs of their customers and investors. Continued funding of the current standard solution encompasses incremental costs and time-to-market.

DIV 1325OT GRE E NSI DE CON F ERE NCE 1320 13 20 SAND T RAP 1323 1322 1321 CON F. RM. 1323 1322 13 21 B1-1 B1-4 CON F. RM 13 25 1213 EASTERN POINT CON F. RM. 1213 CON F. RM. V103 V103 V1 1212 OF F I CE B1-2 B1-3 B1-5 OF F I CE 1326 OF F I CE 13 26 1222 1221 BL A CK IC E 1222 NUB BL E L IGHT 1220 CONF.RM. 12 20 B1-6 VES T IBU LE V1 04 1211 12 12 1211 C1-1 C1-2 C1-3 C1-4 D1-1 D1-2 C1-5 D1-3 C1-6 DEM O L A B 1221 V104 V104 A2-7 B2-1 B2-2 IDF 1327 A2-3 A2-4 A3-4 A2-5 A2-8 A2-9 A2-10 A3-13 1330 PT R/F AX PT R/F AX PLOTTER ARE A 1327 A2-1 A2-2 1327 D2-1 PT R/F AX B2-3 A2-6 12 1 0 OPE N 1210A 1330 ELECTRICAL 1210 D2-2 12 3 0 A3-1 A3-2 A3-7 A3-10 LIBRARY D2-3 D2-4 D3-4 D2-5 D2-7 1209 1209 12 10 D2-6 D2-8 12 0 8 12 08 B3-1 B3-4 B3-7 D3-1 D3-7 D3-1 0 A3-5 A3-8 A3-11 A3-12 A4-4 A3-1 4 A3-1 6 B3-2 B3-8 CONFERE NCE 1308 ROOM A3-3 A4-1 A3-6 A4-2 A3-9 A4-3 A3-15 B3-3 B3-5 B3-6 13 08 1307 ST ORAGE 1307 13 07 1207 1206 OF F I CE 1207 1206 D3-2 C1 0 4 B3-9 C105 C1 0 5 D3-5 D3-6 D3-11 D3-1 2 OPEN OF FICE 12 30 C10 5 COR RIDOR C1 0 4 D3-3 1304 1304 A4-5 B4-1 B4-2 B4-3 QUI ET 1205A C1 0 4 120 5A D3-8 D3-9 D4-5 EM ER. ELEC. QUI ET 1205B 1205B 1304 1309 STOR. 1309 13 09 D4-1 D4-3 D4-7 1305 MEN'S LAV 1305 1306 13 0 5 13 0 6 1204 1204 1306 V107 V107 VES T IBU LE V1 07 1316 13 16 13 15 1315 1314 13 14 OF1313 F ICE 13 13 HAZ ARD 1312 CONF. RM. 13 12 BADGING 1311 SECURIT Y & S AFET Y 13 0 5 A WOMEN' S LAV 1310 D4-2 D4-4 D4-6 D4-8 1310 1203 D4-9 12 03 B5-4 STA GING 1302 B5-1 CAP E NE DDICK CON F. RM. B5-2 1303 BUI LDING SERVICES 1303 13 0 2 1301 1202 COPY/M AIL 13 02 13 01 1201 TRAMMELL CROW COMPANY B5-5 B5-6 12 0 2 BRE AKROOM 1201 1202 1002A 1002 10 02 1301 1002 TOI LET 1001 1001 LOBBY 1001 C106 C1 0 6 C1 0 1 1401 1401 1401 1402A C101 C1 0 1 V102 V101 V1 0 2 14 1 0 B VES T IBULE V1 02 B5-3 V101 VES T IBUL E V1 01 1303A 1101 1101 10 0 1 A 1402 EL E V. M E CH. 1402 1402 1102 1102 D6-1 D6-3 D6-5 D6-7 D6-9 BENCH L AB 1410 1411 1412 1414 1416 LDF 1411 1412 1414 1416 ST ORAGE 14 12 1414 IDF 1411 1416 COR RIDOR C1 0 6 1403 1404 C103 1415 11 0 8 A JAN. 14 0 3 14 03 MEN'S LAV 1404 1404 14 1 5 1404A 1103B 11 0 8 1103 1404A 1108 C1 0 3 SHOW ER BDF ELECTRICAL 140 4A 1415 11 08 WOMEN' S LAV 1103A D6-8 1103A SHOWER D6-2 D6-4 D6-6 1103A COR RIDOR C1 0 2 1103 1103 D7-1 D7-4 D7-7 D7-1 0 D6-10 D7-1 3 C102 D7-2 D7-5 D7-8 D7-1 1 D7-1 4 1410A C103 C1 02 OPEN OF FICE 1130 1104 1104 1106 D7-3 D7-6 D7-9 D7-1 2 D7-1 5 1105 OF F I CE 11 05 D8-1 1130 D8-4 D8-7 D8-1 0 D8-1 3 CA CU 1106 D8-2 1107 D8-5 D8-6 D8-8 D8-1 1 1107 D8-3 D8-9 D8-1 2 D8-1 4 D8-1 5 1504 1504 1504 1502 CHI L L ER PUM P ROOM 1502 1502 ST ORAGE V105 1109 V105 C9-1 D9-1 1505 STA ND-BY SW ITCH GEAR 1505 VES TIBULE V1 05 M OTHERS ROOM 1109 1110 1109 C9-2 C9-3 C9-4 C9-5 C9-6 D9-2 1110 D9-3 D9-4 D9-5 D9-6 BL I ZZ ARD CON F 11. 2 0RM. 1120 1111 1111 1503 TEL EPHONE 1503 1503 1501 1501 BLDG. EL ECTRIC 1501 V106 VES T IBULE V106 V1 06 RECEIVING 15 10 1520 1520 WATER ROOM 15 20 1506 FIRE PUM P ROOM 1506 1506 1507 1507 1115 BIRD ISL AND CONF.RM. 1115 1510 1510 EM ER. 1507 ELECTRIC Evaluating Neutral Host Opportunities Proper evaluation of capacity, signal strength and signal quality for each of the mobile service providers is required to assess the need for a neutral host system. Capacity is evaluated both within the venue of interest as well as in the surrounding macro network. A venue may have adequate signal strength but if the venue hosts a significant number of subscribers, the sites that serve the area may be over utilized. In this scenario a neutral host system may be driven by either a dedicated base station or a repeater that is fed from a less utilized site. Signal quality is an important factor in determining the need for a neutral host system and must be considered for multiple carriers. Signal quality can be measured by using equipment that utilizes sophisticated algorithms to generate Mean Opinion Scores (MOS). Alternative technology specific indicators are also used, such as Bit Error Rate (BER) for GSM networks, Frame Error Rate (FER) for CDMA Networks and Signal Quality Estimate (SQE) for iden networks. Adequate signal strength should not be equated to good signal quality. While signal strength is certainly a factor in determining signal quality it is not uncommon for good signal strength to be present within a building while the signal quality is poor. Interference in one form or another is generally the cause of poor quality occurring in an environment of good signal strength. An example of this is shown in figures 3 and 4 below. Note that in these figures the received signal strength (RSSI) is adequate at the outer edges of the building, but the signal quality (using FER as an indicator) is marginal to poor. Carrier 1 RSSI -85 to 0 dbm -90 to -85 dbm -95 to -90 dbm Less Than -95 dbm 0 50 100 NO. 1 ELEV. NO. 2 EL E V. feet Figure 3: Carrier 1 RSSI

DIV 1325OT GRE ENSI DE CONFERE NCE 1320 1320 SAND TRAP 1323 1322 1321 CONF. RM. 1323 1322 1321 B1-1 B1-4 CONF. RM 1325 1213 EASTERN POINT CONF. RM. 1213 V1 03 VES TIBULE V1 0V103 3 1212 B1-2 B1-3 B1-5 1326 1326 B1-6 V1 04 1211 1212 1211 DEM O LAB 1221 1222 1221 BLACK ICE CONF. RM. 1222 C1-1 C1-2 C1-3 C1-4 D1-1 NUBBLE LIGHT CONF.RM 1220. 1220 D1-2 C1-5 D1-3 C1-6 V1 04 V1 04 A2-7 B2-1 B2-2 IDF 1327 A2-3 A2-4 A3-4 A2-5 A2-8 A2-9 A2-10 A3-13 1330 PLOTTER AREA 1327 A2-1 A2-2 1327 D2-1 B2-3 A2-6 1210 OPE N OF FICE 1210A 1330 ELECTRI 1210 CAL D2-2 1230 A3-1 A3-2 A3-7 A3-10 LIBRARY D2-3 D2-4 D3-4 D2-5 D2-7 1209 1209 1210 D2-6 D2-8 1208 1208 B3-1 B3-4 B3-7 D3-1 D3-7 D3-1 0 A3-5 A3-8 A3-11 A3-12 A4-4 A3-14 A3-16 B3-2 B3-8 CONFERE NCE 1308 ROOM A3-3 A4-1 A3-6 A4-2 A3-9 A4-3 A3-15 B3-3 B3-5 B3-6 1308 1307 1307 1307 1207 1206 1207 1206 D3-2 C104 B3-9 C105 D3-5 D3-6 D3-11 D3-12 OPE N OF FICE 1230 C105 C1 0 4 D3-3 1304 1304 A4-5 B4-1 B4-2 B4-3 QUI ET 1205A C104 1205A D3-8 D3-9 D4-5 EM ER. ELEC. QUI ET 1205B 1205B 1304 1309 STOR. 1309 1309 D4-1 D4-3 D4-7 1305 MEN'S LAV 1305 1306 1305 1306 1204 1204 1306 V107 V107 V1 07 1316 1316 1315 1315 1314 1314 1313 1313 HAZ ARD CONF. 1312 RM. 1312 BADGING 1311 SECURIT Y & SAFET Y 1305A WOM EN' S LAV 1310 D4-2 D4-4 D4-6 D4-8 1310 1203 D4-9 1203 B5-4 STAGING 1302 B5-1 CAP E NE DDICK CONF. RM. 1201 B5-2 TRAMMELL CROW COMPANY 1303 BUI LDING SERVICES 1303 B5-5 B5-6 1302 1301 1202 COPY/MAIL 1302 1301 1202 BREAKROOM 1201 1202 1301 1002A 1002 1002 TOILET 1002 1001 1001 LOBBY 1001 C1 0 6 C106 C101 1401 1401 1401 1402A C101 V102 V101 V102 V101 V1 01 1410B V1 02 B5-3 1303A 1101 1101 1001A 1402 ELEV. M E CH. 1402 1402 1411 1411 1411 1403 JAN. 1403 1102 1102 D6-1 D6-3 D6-5 D6-7 D6-9 1404A 1404A SHOWER 1404A BENCH L AB 1410 C1 0 6 1404 MEN'S LAV 1404 1404 1103A 1103A SHOWER D6-2 D6-4 D6-6 D6-8 1412 1414 1412 1414 1412 1103A C1 0 2 1103B 1103 WOMEN' S LAV 1103 1103 D7-1 D7-4 D7-7 D7-1 0 D6-1 0 D7-1 3 C102 C103 1415 1108A D7-2 D7-5 D7-8 D7-1 1 D7-1 4 C1 0 3 1410A C102 1130 1104 1414 OPE N OF FICE LDF 1415 BDF 1415 1104 1106 D7-3 D7-6 D7-9 D7-1 2 D7-1 5 1105 1105 D8-1 1130 D8-4 D8-7 D8-1 0 D8-1 3 1416 IDF 1416 1416 1106 1108 1108 ELECTRI CAL 1108 D8-2 1107 D8-5 D8-6 D8-8 D8-1 1 1107 D8-3 D8-9 D8-1 2 D8-14 D8-15 1504 1504 1504 1502 CHI L L ER PUM P ROOM 1502 1502 V105 1109 V105 M OTHERS ROOM 1109 C9-1 D9-1 1505 STA ND-B Y SW ITCH GEAR 1505 V1 05 1109 1110 C9-2 C9-3 C9-4 C9-5 C9-6 D9-2 1110 D9-3 D9-4 D9-5 D9-6 BLIZZARD CONF. 1120RM. 1120 1111 1111 1503 TEL EPHONE 1503 1503 1501 1501 BLDG. EL ECTRIC 1501 V106 V106 V1 06 RECEIVING 1510 1520 1520 WA TER ROOM 1520 1506 FIRE PUM P ROOM 1506 1506 1507 1507 1115 BIRD ISL AND CONF.RM. 1115 1510 1510 EM ER. 1507 ELECTRI C Data collection software is used to produce coverage plots as shown in Figures 1 and 2 for each provider. This data can then be used to assess the suitability of the building for neutral hosting as well as to identify the areas of the building that require coverage enhancement. Carrier 1 Frame Error Rate 0 to 2 2 to 3 3 to 5 Greater Than 5 PTR /FAX C105 C101 NO. 1 ELEV. NO. 2 ELEV. C103 0 50 100 feet Figure 4: Carrier 1 Frame Error Rate

DUM PL ING ROCK 2223 CONF. RM. 2223 A1-1 A1-4 B1-1 C1-4 C1-7 C1-1 0 D1-1 NOR'EASTER CONF.RM. 2320 2320 2222 2222 NOR TH E ND 2220 CONF.RM. 2220 A1-2 A1-5 OPE N OF FICE 2330 B1-2 B1-4 B1-5 B1-7 C1-1 2330 B1-8 C1-5 C1-6 C1-8 C1-9 C1-1 1 C1-1 2 D1-2 A1-3 A1-6 B1-3 B1-6 B1-9 C1-2 C1-3 D1-3 2221 2221 PTR /FAX D2-1 D2-3 A2-1 A2-3 A2-5 A2-7 A2-9 231 9 IDF 2319 2319 D2-2 D2-4 D2-5 D2-6 D2-7 D2-8 2210 ELECTRI CAL 2210 2209 2208 2209 A2-2 A2-4 A2-6 A2-8 A2-10 2318 2208 2318 2210A OPE N OF FICE 234 0 D3-1 D3-4 D3-7 D3-1 0 2340 A3-1 A3-4 A3-7 2207 2207 C2 0 5 A3-10 230 7 C20 5 2307 230 7 D3-2 D3-5 D3-8 2230 D3-1 1 A3-2 A3-5 A3-8 A3-11 B3-1 B3-3 B3-5 2206 2206 2306 STOR. 2306 2306 OPEN OF FICE 2230 A3-3 A3-6 A3-9 A3-12 B3-2 B3-4 B3-6 C2 0 5 C206 D3-3 JAN. 2304 2304 D3-6 D4-3 D3-9 C2 0 6 2304 QUI ET 2205A 2205A QUI ET 2205B 2205B D4-1 D4-5 D3-1 2 D4-7 CONF.RM 2312. 2312 MEN'S 2303LAV 2303 2305 2305 230 3 WOM EN' S LAV 2305 2317 2317 2316 2315 2315 2314 2314 2313 2313 SNOW BANK 2204 2316 2204 2305A D4-2 D4-4 D4-6 D4-8 D4-9 2203 2203 2302 2302 2301 C201 STOR. 2401 2302 2202 BRE AKROOM 2202 CUT TYHUNK L IGHT CONF.RM 2201. 2201 2301 2309 2309 MAIL/COPY 2301 2200 2310 2310 DAT A CE NTER NOC 2309 2310 C2 0 7 C201 C207 C201 V20 1 V201 1 PDU PDU 2405A C2 0 7 2401 2401 2405 2404 FM 200 2405 2405 2403 NOC 2403 2101A 2202 2101 2200A 2403 2402 STAGING 240 2 2402 2102 210 2 DAT A CE NTER D6-1 D6-2 D6-3 D6-5 D6-7 CAC U RM. 2404 240 4 2103 2103 D6-4 D6-6 D6-8 D6-9 D6-1 0 2406 2406 2407A 2407 2407 WOMEN'S LAV 240 7 2410A CAC U QUI E2105A T 210 5A QUI E T 2102105B 5B 2410D MEN'S 2406 LAV C20 3 2104 210 4 D7-1 D7-4 D7-7 D7-1 0 D6-1 3 C2 0 2 C202 IDF 2412 2412 2412 C2 0 3 D7-2 D7-5 D7-8 D7-1 1 D7-1 4 C203 240 8 STOR. 2408 2408 OPE N 2130 C2 0 2 2409 2409 2409 2106 2107 2106 2107 D7-3 D7-6 D7-9 D7-1 2 D7-1 5 D8-1 2130 D8-4 D8-1 0 D8-1 3 2411 2110A 211 0 ELE CTRI CAL 2110 2110 2411 D8-2 D8-5 D8-7 D8-8 D8-11 D8-14 BENCH L AB 2410 2108 2109 2108 2109 D8-3 PTR /FAX D8-6 D8-9 D8-1 2 D8-1 5 2410 2111 2111 C9-1 C9-4 D9-1 D9-4 C9-2 C9-5 D9-2 D9-5 BIG DIG 2120 CONF.RM. 2120 2421 2421 C9-3 C9-6 D9-3 D9-6 2410B 2410C CAC U 2115 DEE R ISL AND CONF.RM. 2115 Site Survey A site survey is performed prior to the final design. The objective of the survey is to characterize signal propagation within the building, investigate donor signal options and to investigate equipment space and cable routing issues. Proper engineering and planning will minimize capital expenditures while ensuring that coverage goals for each of the mobile service providers are met. Several factors must be considered when designing a neutral hosts system. Assuming the target coverage area has been identified as described above, the first of these is to characterize signal propagation within the target area. To characterize the building test transmitters are located at various locations within the building. A receiver and mapping software is used to record the signal strength at various locations within the building. A sample transmitter test is shown in Figure 5 below. Transmitter Location Transmitter Test Path Loss -85 to 0-90 to -85-95 to -90 all others ELEV. NO. 1 NO. 2 ELEV. 0 50 100 feet Figure 5: Transmitter/Building Characterization Test Various transmitter tests are performed so that a thorough understanding of the building s propagation characteristics is obtained. As can be seen from the transmitter test in figure 3 signal loss does not degrade in direct proportion to the distance from the transmitter but is largely dependant on the building structure. Using the proper tools and procedures to characterize signal loss helps to insure that the system is not over designed but meets customer requirements.

Suitable equipment room space and it s proximity to the coverage objective can affect the type of system installed and overall cost of the system. These issues are investigated at the time of the site survey. Potential donor signals are also investigated for neutral host opportunities that may not require dedicated base stations. These measurements are generally performed at the roof level. A receiver capable of measuring multiple technologies and frequencies is required for these measurements. Alternatively phones from various carriers with an accessible diagnostic or debug mode can be used. Potential donor antenna locations and roof penetration issues also need to be investigated at this stage. System Design The building characterization along with available equipment space determined during the site survey is the basis for system design. The propagation model is optimized for accuracy using the transmitter tests performed in the site survey. Each wall type within a building affects signal propagation differently therefore each wall type must be identified in the propagation model and assigned attenuation values obtained from the information in the transmitter tests. This allows for optimum transmitter location and minimizes required capital. The system design determines which OEM hardware solution is appropriate for the venue. A partial design (one floor of a multi story building) is shown in figure 6 below. Figure 6: System Design

Construction Once the proposed design is approved for installation by the building manager, a preconstruction site visit is completed. During this visit, equipment locations and cable routes are verified, as well as acceptable contractors to perform any electrical or roofing work that may be required. If any of the locations proposed in the design are not acceptable to the building manager, the design is modified to allow for these changes. Once final approval is obtained, the actual installation of equipment begins. Construction begins with the installation of cabling, typically both fiberoptic and coaxial. Cabling is routed from the main equipment room throughout the building to all the antenna locations. A DAS system allows for the reuse of many network elements such that trunking and hubbing minimize the amount of new cable required. Cable is run in existing cable trays or utility chases where available. The equipment deployment is fairly straight forward. The main equipment room typically needs dedicated electrical services to handle both the DAS equipment and the carrier equipment. The remote units and the antenna use minimal power and usually only involve a 10v outlet.

Optimization and Verification Upon completion of the construction phase, the system is tested and optimized. Each coax and fiber optic cable is swept, isolation tests are performed, sources of interference are investigated, donor signal levels are verified, and a final coverage assessment is performed. The results of the coverage analysis reflect both coverage provided by the external macro cell and enhanced coverage provided by the DAS. Figures 7 and 8 below show sample plots that can be used to measure the success of the installation. Figure 7: Carrier 1 RSSI - Post Activation

Figure 8: Carrier 1 Frame Error Rate - Post Activation The results of the post activation survey can be used to evaluate the success of the installation and used as a baseline to help troubleshoot problems if they arise in the future. Summary A well designed Distributed Antenna Systems (DAS) can provide a cost efficient interference-free environment for indoor CDMA, TDMA, GSM, iden, LMR, DCS, GPRS and WiFi 802.11x networks. Using a combination of high-tech test equipment, custom software applications, and engineering procedures, a design-driven neutral host DAS network can be implemented that minimizes capitol investment, controls operating expenses, and meets the network coverage objectives.