Cell Splitting

When the number of subscribers in a given area increases allocation of more channels covered by that channel is necessary, which is done by cell splitting. A single small cell midway between two co-channel cells is introduced. 

Cell Splitting

Cellular Networks

A Cellular Network is formed of some cells. The cell covers a geographical region and has a base station analogous to 802.11 AP which helps mobile users attach to the network and there is an air interface of physical and data link layer protocol between mobile and base station. All these base stations are connected to the Mobile Switching Center which connects cells to a wide-area net, manages call setup, and handles mobility. 

There is a certain radio spectrum that is allocated to the base station and to a particular region and that now needs to be shared. There are two techniques for sharing mobile-to-base station radio spectrum: 

  • Combined FDMA/TDMA: It divides the spectrum into frequency channels and divides each channel into time slots.
  • Code Division Multiple Access (CDMA): It allows the reuse of the same spectrum over all cells. Net capacity improvement. Two frequency bands are used one of which is for the forwarding channel (cell-site to subscriber) and one for the reverse channel (sub to cell-site).

Similar Reads

Cell Fundamentals

In practice, cells are of arbitrary shape(close to a circle) because it has the same power on all sides and has same sensitivity on all sides, but putting up two-three circles together may result in interleaving gaps or may intersect each other so order to solve this problem we can use equilateral triangle, square or a regular hexagon in which hexagonal cell is close to a circle used for a system design. Co-channel reuse ratio is given by:...

Cell Splitting

When the number of subscribers in a given area increases allocation of more channels covered by that channel is necessary, which is done by cell splitting. A single small cell midway between two co-channel cells is introduced....

Need for Cellular Hierarchy

Extending the coverage to the areas that are difficult to cover by a large cell. Increasing the capacity of the network for those areas that have a higher density of users. An increasing number of wireless devices and the communication between them....

Fixed Channel Allocation

For a particular channel, the frequency band which is associated is fixed. The total number of channels is given by...

Global System for Mobile (GSM) Communications

GSM uses 124 frequency channels, each of which uses an 8-slot Time Division Multiplexing (TDM) system. There is a frequency band that is also fixed. Transmitting and receiving do not happen in the same time slot because the GSM radios cannot transmit and receive at the same time and it takes time to switch from one to the other. A data frame is transmitted in 547 microseconds, but a transmitter is only allowed to send one data frame every 4.615 microseconds since it is sharing the channel with seven other stations. The gross rate of each channel is 270, 833 bps divided among eight users, which gives 33.854 kbps gross....

Control Channel (CC)

Apart from user channels, there are some control channels which is used to manage the system....

Common Control Channel

Three logical sub-channels are:...

Advantages of Cellular Networks

Mobile and fixed users can connect using it. Voice and data services also provided. Has increased capacity & easy to maintain. Easy to upgrade the equipment & has consumes less power. It is used in place where cables can not be laid out because of its wireless existence. To use the features & functions of mainly all private and public networks. Can be distributed to the larger coverage of areas....

Disadvantages of Cellular Networks

It provides a lower data rate than wired networks like fiber optics and DSL. The data rate changes depending on wireless technologies like GSM, CDMA, LTE, etc. Macrophage cells are impacted by multipath signal loss. To service customers, there is a limited capacity that depends on the channels and different access techniques. Due to the wireless nature of the connection, security issues exist. For the construction of antennas for cellular networks, a foundation tower and space are required. It takes a lot of time and labor to do this....