3D CELLULAR NETWORK

An Innovative Solution For

Cellular Signal Coverage In High-Rise Buildings

 Inventor:  Mr. Yuan Xie

High-rise Coverage Problem

 All incumbent cellular networks around the world are actually two-dimensional space coverage networks. Their base station antennas are down-tilted to beam downward cellular signals to cover the ground and meanwhile to avoid frequency interferences. Fig.1 shows 3D view of coverage of typical cellular network. It looks like many large flat domes laying aside each other on the ground. Only the ground and part of space below their base station antennas is under its coverage. However, there is large space above the ground is outside its coverage. Most high-rise buildings in city are standing outside its coverage. It results serious coverage problem in upper part of high-rise buildings in city. This is the infrastructure defect of cellular network that is commonly unaware. Because of poor cellular signals or no cellular signals at all in their working or living places in high-rise buildings, tens millions people around the world can't get satisfied cellular communications services.

 Figure 1: 3D view of coverage of incumbent cellular network

3D Cellular Network Solution

 Our solution to high-rise coverage problem is three-dimensional space coverage cellular network. It establishes on your existing cellular network and converts its macro cells in city into 3D cells. 3D cell has three-dimensional space coverage extent, covering ground, lower and upper space above ground in its cell. Its coverage has columnar shape and is much higher in elevation than conventional macro cell's coverage. Figure 2 shows 3D view of coverage of 3D cellular network. It looks like many large columns laying aside each other on the ground. In 3D cellular network, ground and all buildings, no matter low-rise or high-rise, are covered. It solves the coverage problem of high-rise buildings. With 3D cell solution, cellular signal inside upper floors of high-rise buildings improves 10 to 100 times (10 to 20dB gain) than before. 3D cellular network is an innovative remedy of the infrastructure defect of cellular network in space coverage. The invention how to realize 3D cellular network and meanwhile avoid interference is patent protected around the world. It has been granted patent in Canada, Europe, China, Hong Kong, India, Singapore and South Africa.

 Figure 2: 3D view of coverage of 3D cellular network

Features of 3D Cellular Network

 3D cellular network shares your existing cellular network infrastructure and adopts macro cell coverage strategy. Infrastructure sharing makes it minimum equipment investment and time to set up. Macro cell coverage strategy makes its coverage most cost-efficient.  It improves cellular signal inside upper floors of most high-rise buildings 10 to 100 times (10 to 20dB gain) than before and to reach a level (about -85dBm in average) strong enough to carry quality cellular communications. One 3D cell can cover tens high-rise buildings inside its cell with equipment investment less than ten thousands US dollars and only weeks of time to implement. 3D cellular network can effectively cover hundreds even thousands high-rise buildings in a city with equipment investment of few hundreds thousands US dollars and time less than one year to implement. That is unimaginable for conventional indoor coverage solution.

 3D cellular network shares your existing cellular frequencies. No new frequency is required for this solution. That is a release for carrier with tight frequency resources. More important, this solution doesn't cause frequency interferences to your existing cellular network.

 3D cellular network solution works in any type cellular technology and in any cellular frequency band. No matter your cellular network adopts TDMA, or GSM, or CDMA, or 3G, or WiMAX technology etc., or it is mobile cellular network or fixed cellular network, 3D cells can be utilized in it for high-rise coverage.  Multi-band 3D cellular network can help release capacity pressure caused by increased coverage space, subscribers and call time in high-rise buildings.

3D cell covers hills and mountains. Cellular carriers can utilize 3D cells to maximize their existing cellular networks' coverage in hills and mountains and minimize their network infrastructure investment. With 3D cell, base station can be set up at mountain valley or hill footage where power supply and communication transmission lines are usually available and avoid to be set up on top of mountain or hill where power supply and communication transmission lines usually are not available. It will save huge infrastructure investment for cellular carriers. 3D cell also give cellular carriers more freedom in selection of base station site in mountainous areas.

3D cell covers the sky. Cellular carriers can utilize 3D cells to enable their cellular networks to cover airlines in the future.

Benefits of 3D Cellular Network

 High-rise buildings, or city top, is the largest "blind space" of incumbent cellular networks, where should be covered but uncovered with cellular signals. 3D cellular network provides an innovative and satisfying solution for cellular signal coverage in city top.  It benefits both cellular carriers and customers.

 Improved Coverage and Quality of Service:

 The demand for cellular signal indoor coverage is keeping increase. Nowadays more cellular communications happen indoors than outdoors. Customers on city top often find themselves either without cellular signals at all or encountering difficulties to maintain cellular connections. With 3D cellular network solution, cellular signals are significantly improved there. Customers benefit much better signal reception, improved call clarity, higher data throughput, and longer lasting connection than before inside upper floors of high-rise buildings. Cellular carriers benefit added new customers and increased call time. It results increased customers' satisfaction and carrier's revenue.

 Investment Saving: 

 3D cellular network is a macro cell "wireless solution" for indoor cellular coverage. Its coverage in high-rise buildings is extremely efficient.  Furthermore, its sharing of the infrastructure of incumbent cellular network eliminates expensive infrastructure investment and the need of cellular frequencies. These make 3D cellular network solution extremely economic. For example, one 3D cell can cover tens high-rise buildings in its cell with equipment investment as little as thousands US dollars. This is incomparable to conventional indoor coverage systems that often cost tens millions US dollars to achieve the same level coverage in these high-rise buildings. The 3D cellular network can also greatly reduce infrastructure investment for cellular carriers in mountainous areas.

 Time Saving:

 3D cellular network establishes on incumbent cellular network infrastructure. Its set-up involves only modification of cellular base stations and is irrelevant to high-rise buildings themselves. It is extremely time saving. For example, a 3D cell can be set up in just days and it can cover tens high-rise buildings in its cell. 3D cellular network can be set up in just months and it can cover hundreds even thousands high-rise buildings in city. This is incomparable to conventional indoor coverage solution that often takes months to finish coverage in one high-rise building. Image how long it will take to cover hundreds even thousands high-rise buildings in a city with conventional indoor coverage solution.

 Increased Competency:

 Coverage quality is one of key factors affecting customers' choice of cellular network. The distinctive coverage in high-rise buildings of 3D cellular network gives its cellular carrier niche to win market competition. It may be fatal without high-rise coverage for carriers in city like Hong Kong or New York where high-rise are dominate buildings.

Comparison With DAS Indoor Coverage Solution

 Conventional solution for indoor cellular coverage is distributed antenna system (DAS). It provides cellular signal from a base station or a repeater, then distributes it through a RF/fiber cable network and radiates it out from numerous indoor antennas inside the buildings. The cable network runs through the entire building from corner to corner and floor by floor. It is "wired" solution for wireless indoor coverage. It has been adopted in cellular signal indoor coverage in shopping malls, airport, subways and office buildings including high-rise buildings etc.

 "Wired" way of distributed antenna system makes it very inefficient. Cellular signal loses most of its energy when it is distributed through the RF/fiber cable network. Most buildings are not pre-equipped with such RF/fiber cable network when they were built. It has to be newly planed, designed and installed to fit each individual building when needed. That involves tremendous work on data collection of building structure, site survey, system design and installation. Nothing can start without building landlord's permission for the system. Expenses related to its system equipment, design, installation, space rental and maintenances are extraordinary. The whole process can last months for single building coverage. Image how long it will take to finish indoor coverage in hundreds even thousands high-rise buildings in a city. The distributed antenna system is also frequency band sensitive. It needs to be upgraded to function properly when new frequency band (3G, for example) is added to the cellular network. All of these factors decide the distributed antenna system solution for cellular indoor coverage is very inefficient, complex, difficult, expensive and time consuming.  For example, it usually costs cellular carrier hundreds thousands US dollars of investment and months of time to accomplish coverage inside a 30-floor high-rise office building. With limited subscribers and call time under its coverage, cellular carriers usually find it difficult to justify the ROI (return of investment) for such system. The distributed antenna system is not a practical solution. That's why cellular carriers around the world rarely adopt it to cover high-rise buildings and leave them uncovered for years.

 3D cellular network is coverage revolution for high-rise. Macro cell wireless coverage approach of its 3D cell is extremely efficient. Its implementation relates to base station modification only and has nothing to do with high-rise buildings.  All these decide it is very efficient, simple, easy, economic and time saving. It has incomparable advantages over distributed antenna system.  It delivers similar quality coverage inside high-rise buildings in a fraction of the cost and time of the distributed antenna system needs. 3D cell is practical solution for high-rise coverage. Let 3D cellular network lights up our "cellular dark" city top!

 Table 1 gives extensive comparison of the two solutions in such as cost, coverage, capacity, interference, implementation and maintenance etc. 3D cell solution is clear winner in cost, implementation and maintenance over DAS solution. According to different donors, table 1 lists two types DAS, repeater and base station. Repeater DAS shares its macro cell capacity and it is relatively inexpensive. Base station DAS has its own capacity to serves its indoor coverage area only. But it is very expensive. 3D cell doesn't cover underground. So wherever underground coverage is necessary, DAS delivers the solution there.