channel assignment strategies, handoff strategies improvement in

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Channel Assignment Strategies, Handoff Strategies Improvement in Coverage and Capacity(Sectoring splitting and Microcell zoning)

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Channel Assignment Strategies

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Channel Assignment Strategies, Handoff Strategies Improvement in Coverage and Capacity(Sectoring splitting and Microcell zoning)

Channel Assignment Strategies, Handoff Strategies Improvement in Coverage and Capacity(Sectoring splitting and Microcell zoning)For Efficient utilization of spectrum Concept of frequency reuse Co-channel interference reduction factorDesired carrier to noise ratioHandoff mechanism

2TerminologiesCellular ConceptTo replace a single, high power transmitter with many low power transmitters, each providing coverage to a small geographical areaNeighboring base stations are assigned different groups of channels so that interference between base stations are minimized

AdvantagesNo need for high power and high antennasCan plan for frequency reuse

Frequency ReuseEach base station is allocated a group of radio channels with in a geographical area called a cellChannel groups can be carefully selected and allocated to different base stations for efficient spectrum utilitySectored directional antennas are used for corner-excited cells.TerminologiesBasestationThe fixed transmit/receive unit that serves each geographical unit

CellGeographical area covered by a single basestationMost commonly used cell shape is hexagon

Downlink or Forward Link(s)Link from base station to user(s)

Uplink or Reverse Link(s)Link from user(s) to base station

Co-channel CellsCells that use the same set of frequencies

Footprints Actual coverage of cell.

Terminologies

Co-channel InterferenceInterference between cochannelcells

Cell ClusterThe space between adjacent cochannelcells can be filled with other cells that use different frequencies to provide frequency isolation. A group of cells that use a different set of frequencies in each cell is called a cellcluster

Cluster SizeNumber of cells in a cluster

Mobile Switching Centereach of the base stations in the cluster is connected to a mobile switching center (MSC) by wire lines

Frequency Reuse

Suppose there are a total of S duplex frequency channels available for use in a cellular system.

If each cell is allocated a group of k channels (k