Current Cellular Standards The cell

Current Cellular Standards The cellular solution, originally designed by Bell Telephone laboratories in the 1970's makes use of multiple fixed stations. Each station, located in what is termed a "cell" services subscriber stations within a limited geographical area. Cellular companies are each granted 25 Mhz of the spectral division in the 800-900 Mhz region, each split between the two directions of communications. Typical analog systems such as AMPS employ FDMA schemes that divide the spectral allocations into uniform frequency channels in the range of 25-30 kHz wide. Applying simple algebra shows the approximate number of channels to be around 416. This number, although appearing somewhat large, is rather small with respect to data communications. Different types of cellular systems employ various methods of " multiple access", meaning that multiple, simultaneous users can be supported. These users share a common pool of radio channels and can gain access to any channel. Just as each telephone call is granted a specific line for discourse, each subscriber is assigned a unique channel to propagate data transmission. Only one subscriber at a time is assigned to each channel; no other conversations can access it until the call is completed. These channels are a limited resource of cellular companies, as are the number of phone lines for Ma Bell. Solutions to achieve greater capacity are central to cellular principles. Spectral allocations are limited for each cell, due in part to regulatory agencies limiting the bandwidth in order for communication companies to create highly efficient solutions. This spectral efficiency is measured in Erlangs per unit service area, per MHz. Quite simply, this dimensionless unit of telephone traffic intensity, known as the Erlang blocking probability (typically 0.05), is equal to calling rate multiplied by the average call length. This shows the capacity for a channel to be completely occupied for some given time frame, with higher values representing higher channel usage. Due to the explosive growth of the cellular industry exceeding initial predictions of analysts, subscribers in many urban cities often experience "blocking" with the trend increasing as the number of wireless LAN's and personal cellular radios continue to grow. Anyone who has tried to make a call and has been prevented or "blocked" will understand this concept. One in six Los Angeles subscribers experiences blocking during peak hours. Many subscribers also experience "dropped calls" when leaving one cell and moving into another when the new cell can't allocate a carrier channel to the mobile. Consequently, this leads to poor customer relations which forces the cellular providers to arrive at solutions that achieve high spectral efficiency to increase cell capacity. Central to the cellular concept is frequency reuse, which is critically dependent upon the fact that the carrier wave power decays with increasing distance. With this information, and some physics (which we won't get into), a cellular division of frequency channels can be implemented. It's the same rationale when travelling long distances: your favorite radio show on a familiar frequency is not the same in each city. The channel is allocated to another radio station far enough apart where signals won't interfere with each other. By reusing channels in multiple cells, the system can grow without geographical limits. Here each cell represents an allocation of channels where no adjacent cells share common frequencies, with a typical maximum subscriber load at about 350 users. This idealized depiction is a hypothetical representation of true cellular systems that is good for modeling, but unfortunately not substantial enough for real world implementations of cellular technology.

Результаты (английский) 1:

Cellular Standards Current
of The cellular Solution, Originally the Designed by Bell Telephone Laboratories in the 1970's makes use of multiple fixed stations. Each station, located in what is termed a "cell" services subscriber stations within a limited geographical area. Cellular companies are each granted 25 Mhz of the spectral division in the 800-900 Mhz region, each split between the two directions of communications. Typical analog systems such as AMPS employ FDMA schemes that divide the spectral allocations into uniform frequency channels in the range of 25-30 kHz wide. Applying simple algebra shows the approximate number of channels to be around 416. This number, although appearing somewhat large, is rather small with respect to data communications.
Different types of cellular systems employ various methods of "multiple access", meaning that multiple, simultaneous users can be supported. These users share a common pool of radio channels and can gain access to any channel. Just as each telephone call is granted a specific line for discourse, each subscriber is assigned a unique channel to propagate data transmission. Only one subscriber at a time is assigned to each channel; no other conversations can access it until the call is completed. These channels are a limited resource of cellular companies, as are the number of phone lines for Ma Bell. Solutions to achieve greater capacity are central to cellular principles.
Spectral allocations are limited for each cell, due in part to regulatory agencies limiting the bandwidth in order for communication companies to create highly efficient solutions. This spectral efficiency is measured in Erlangs per unit service area, per MHz. Quite simply, this dimensionless unit of telephone traffic intensity, known as the Erlang blocking probability (typically 0.05), is equal to calling rate multiplied by the average call length. This shows the capacity for a channel to be completely occupied for some given time frame, with higher values ​​representing higher channel usage. Due to the explosive growth of the cellular industry exceeding initial predictions of analysts, subscribers in many urban cities often experience "blocking" with the trend increasing as the number of wireless LAN ' s and personal cellular radios continue to grow. Anyone who has tried to make a call and has been prevented or "blocked" will understand this concept. One in six Los Angeles subscribers experiences blocking during peak hours. Many subscribers also experience "dropped calls" when leaving one cell and moving into another when the new cell can not allocate a carrier channel to the mobile. Consequently, this leads to poor customer relations which forces the cellular providers to arrive at solutions that achieve high spectral efficiency to increase cell capacity. when leaving one cell and moving into another when the new cell can not allocate a carrier channel to the mobile. Consequently, this leads to poor customer relations which forces the cellular providers to arrive at solutions that achieve high spectral efficiency to increase cell capacity. when leaving one cell and moving into another when the new cell can not allocate a carrier channel to the mobile. Consequently, this leads to poor customer relations which forces the cellular providers to arrive at solutions that achieve high spectral efficiency to increase cell capacity.
Central to the cellular concept is frequency reuse, which is critically dependent upon the fact that the carrier wave power decays with increasing distance. With this information, and some physics (which we will not get into), a cellular division of frequency channels can be implemented. It's the same rationale when travelling long distances: your favorite radio show on a familiar frequency is not the same in each city. The channel is allocated to another radio station far enough apart where signals will not interfere with each other. By reusing channels in multiple cells, the system can grow without geographical limits.
Here each cell represents an allocation of channels where no adjacent cells share common frequencies, with a typical maximum subscriber load at about 350 users. This idealized depiction is a hypothetical representation of true cellular systems that is good for modeling, but unfortunately not substantial enough for real world implementations of cellular technology.

Результаты (английский) 2:

Current Cellular Standards
The cellular solution, originally designed by Bell Telephone laboratories in the 1970's makes use of multiple fixed stations. Each station, located in what is termed a "cell" services subscriber stations within a limited geographical area. Cellular companies are each granted 25 Mhz of the spectral division in the 800-900 Mhz region, each split between the two directions of communications. Typical analog systems such as AMPS employ FDMA schemes that divide the spectral allocations into uniform frequency channels in the range of 25-30 kHz wide. Applying simple algebra shows the approximate number of channels to be around 416. This number, although appearing somewhat large, is rather small with respect to data communications.
Different types of cellular systems employ different methods of "multiple access", meaning that multiple, simultaneous users can be supported. These users share a common pool of radio channels and can gain access to any channel. Just as each telephone call is granted a specific line for discourse, each subscriber is assigned a unique channel to propagate data transmission. Only one subscriber at a time is assigned to each channel; No other conversations can access it until the call is completed. These channels are a limited resource of cellular companies, as are the number of phone lines for Ma Bell. Solutions to achieve greater capacity are central to cellular principles.
Spectral allocations are limited for each cell, due in part to regulatory agencies limiting the bandwidth in order for communication companies to create highly efficient solutions. This spectral efficiency is measured in Erlangs per unit service area, per MHz. It's not a long-for This shows the capacity for a channel to be completely occupied for some given time frame, with higher values representing higher channel usage. Due to the explosive growth of the cellular industry initial exceeding predictions of analysts, subscribers in many urban cities often experience "blocking" with the trend increasing as the number of wireless LAN's and personal cellular radios continue to grow. Anyone who has tried to make a call and has been prevented or "blocked" will understand this concept. One in six Los Angeles subscribers experiences blocking during peak hours. Many subscribers also experience "dropped calls" when leaving one cell and moving into another when the new cell can't allocate a carrier channel to the mobile. Consequently, this leads to poor customer relations which forces the cellular providers to arrive at solutions that achieve high spectral efficiency to increase cell capacity.
Central to the cellular concept is frequency reuse, which is critically dependent on the fact that the carrier wave power decays with increasing distance. With this information, and some physics (which we won't get into), a cellular division of frequency channels can be implemented. It's the same rationale when traveling long distances: your favorite radio show on a familiar frequency is not the same in each city. The channel is allocated to another radio station far enough apart where signals won't interfere with each other. By reusing channels in multiple cells, the system can grow without geographical limits.
Here each cell represents an allocation of channels where no adjacent cells share common frequencies, with a typical subscriber maximum load at about 350 users. This idealized depiction is a hypothetical representation of true cellular systems that is good for modeling, but unfortunately not substantial enough for real world implementations of cellular technology.

Результаты (английский) 3:

Current Cellular Standards
The cellular solution，originally designed by Bell Telephone laboratories in the 1970's makes use of multiple fixed stations. Each station，located in what is termed a“cell”services subscriber stations within a limited geographical area. Cellular companies are each granted 25 Mhz of the special division in the 800-900 Mhz region，each split between the two directions of communications. 9.Typical analog systems such as AMPS employ FDMA schemes that divide the special allocations into uniform frequency channels in the range of 25-30 khz wide. Applying simple algebra shows the approximate number of channels to be around 416. This is a number, which appears some large, which is her small, with respect to data communications
Different types of cell systems employ variable methods of "multiple access", meaning that multiple, simple users can be supported These users share a common radiation mode and can enter any channel. As a single telephone call is a special thread, each subscriber is assigned a unique channel to propagate data transmission. Only one subscriber at a time is assigned to each channel; no other conversations can access it until the call is completed These mechanisms are a limited resource of cellular companies, a number for the Ma bell phone line. The solution is to realize the greater capability is the core cell principles.
Spectal allocations are limited for each cell，due in part to regulatory agencies limiting the bandwidth in order for communication companies to create highly efficient solutions. This is a particularly effective measure in Erlangs per unit service area, per MHz. Quite simply，this dimensionless unit of telephone traffic intensity，known as the Erlang blocking probability）（typically 0.05），is equal to calling rate multiplied by the average call length. This shows that a mechanism can complete some time frame locking, and has high value to represent high-level channel usage. Due to the explosive growth of the cellular industry exceeding initial predictions of analysts，subscribers in many urban cities often experience”blocking“with the trend increasing as the number of wireless LAN s and personal cellular radios continue to grow. Anyone trying to make a phone call that has been prevented or blocked "will understand the concept. In six Los Angeles subscribers experiences blocking peak hours. Many subscribers also experience”dropped calls“when leaving one cell and moving into another when the new cell can”t allocate a carrier channel to the mobile. Consequently，this leads to poor customer relations which forces the cellular providers to arrive at solutions that achieve high spectral efficiency to increase cell capacity.
Central to the cellular concept is frequency reuse，which is critically dependent upon the fact that the carrier wave power decays with increasing distance. With this information, and some physical（ "It's the same reason when traveling long distances: your family's frequency in one family is not the same in each city. The channel is allocated to another radio station far enough apart where signals won'”t interfere with each other. In many cases, the system can grow without geographic limits.
Here each cell represents an allocation of channels where no adjacent cells share common frequencies，with a typical maximum subscriber load at about 350 users. This idealized depiction is a hypothetical representation of true cellular systems that is good for modeling，but unfortunately not substantial enough for real world implementations of cellular technology.