Cellular Network Techniques and Challenges

The ratio of total channels to channels available per cell in a cluster.

A method where specific channels are assigned to each cell permanently.

Channels are allocated on-demand for individual call requests instead of being fixed.

Methods used to transfer an ongoing call from one cell to another without dropping the call.

The threshold signal strength required for a call to be accepted at a base station.

Allows a cell to use channels from a neighboring cell when its channels are busy.

A formula used to calculate the co-channel reuse ratio in cellular networks.

The need for handoffs to occur successfully and frequently to maintain call quality.

A system providing wireless connection to the PSTN within radio range for users.

Accommodates many users, high quality service, and efficient channel use.

A small geographical area covered by a base station in a cellular system.

Allows uninterrupted processing when moving between cells.

High power, large cells, and limited users lead to poor service and call drops.

Refers to the limitations in user connectivity and functionality in conventional systems.

Refers to how effectively frequency bands are used in mobile communications.

The idea of using multiple low power transmitters to cover small areas instead of one large transmitter.

The signal strength level required to switch from one base station to another without dropped calls.

Interference that occurs when multiple calls use the same frequency in nearby cells.

Interference from signals on frequencies close to the desired frequency.

The practice of using the same frequency in different cells to maximize capacity.

A measure comparing the level of a desired signal to the level of background interference.

The number of cells under which frequencies are reused; impacts interference and capacity.

The minimum distance required between co-channel cells to mitigate interference.

A ratio measuring the relative time a cell is active compared to inactive; affects interference.

The margin defining the handoff requirement, affecting call quality.

Occurs when a call is lost due to weak signal or delay in handoff.

Includes signal drop, vehicle movement, and speed affecting handoff necessity.

The time a call can be maintained without a handoff.

A percentage of channels reserved for ongoing call handoffs.

The delay before handoff due to finite signal interruptions.

Using varying antenna sizes for different user speeds in coverage areas.

When strong signals from pedestrians cause slow transfer between cells.

Achieved by careful filtering and assigning non-adjacent channels in close cells.

Dividing large cells into smaller ones to increase capacity and accommodate more users.

Include shorter coverage distance, lower antenna weight, and improved frequency reuse.

Increased capacity, enhanced frequency reuse, and better call quality without interference.

Includes infrastructure cost, increased co-channel interference risk, and handoff overhead.

In densely populated areas, cells are closer together leading to high signal density and potential interference.

Techniques like cell splitting and sectoring are essential to meet rising demand for wireless services.

A technique dividing a cell into sectors served by directional antennas, reducing interference.

Antennas that focus signals within a specific area, improving signal strength and coverage.

A cell division into three sectors, each covering 120 degrees, for improved frequency reuse.

Requires precise alignment and design to avoid interference at sector boundaries.