frequency reuse

Digital Enhanced Cordless Telecommunications Radio links 1 If frequency-hopping is avoided, each base station can provide up to 120 channels in the DECT spectrum before frequency reuse

Cellular network Frequency reuse 1 The key characteristic of a cellular network is the ability to re-use frequencies to increase both coverage and capacity. As described above, adjacent cells must use different frequencies, however there is no problem with two cells sufficiently far apart operating on the same frequency. The elements that determine frequency reuse are the reuse distance and the reuse factor.

Cellular network Frequency reuse 1 The frequency reuse factor is the rate at which the same frequency can be used in the network. It is 1/K (or K according to some books) where K is the number of cells which cannot use the same frequencies for transmission. Common values for the frequency reuse factor are 1/3, 1/4, 1/7, 1/9 and 1/12 (or 3, 4, 7, 9 and 12 depending on notation).

Cellular network Frequency reuse 1 Code division multiple access-based systems use a wider frequency band to achieve the same rate of transmission as FDMA, but this is compensated for by the ability to use a frequency reuse factor of 1, for example using a reuse pattern of 1/1

Cellular network Frequency reuse 1 Recently also orthogonal frequency- division multiple access based systems such as LTE are being deployed with a frequency reuse of 1

Code division multiple access Spread-spectrum characteristics of CDMA 1 Frequency reuse is the ability to reuse the same radio channel frequency at other cell sites within a cellular system

Microwave 1 Microwaves are especially suitable for this use since they are more easily focused into narrow beams than radio waves, allowing frequency reuse; their comparatively higher frequencies allow broad bandwidth and high data transmission rates, and antenna sizes are smaller than at lower frequencies because antenna size is inversely proportional to transmitted frequency

History of mobile phones - Cellular concepts 1 The concepts of frequency reuse and handoff, as well as a number of other concepts that formed the basis of modern cell phone technology, were described in the late 1960s, in papers by Frenkiel and Porter

Digital radio - Two-way digital radio standards 1 The key breakthrough or key feature in digital radio transmission systems is that they allow lower transmission power, they can provide robustness to noise and cross-talk and other forms of interference, and thus allow the same radio frequency to be frequency reuse|reused at shorter distance

CDMA - Spread-spectrum characteristics of CDMA 1 Frequency reuse is the ability to reuse the same radio channel frequency at other cell sites within a cellular system

Greenfield project - Cellular networks 1 They were developed with no regard for future capacity considerations or frequency reuse

Extremely high frequency 1 The small wavelength allows modest size antennas to have a small beam width, further increasing frequency reuse potential.

Extremely high frequency - Propagation 1 Millimeter waves travel solely by line-of- sight propagation|line-of-sight, and are blocked by building walls and attenuated by foliage. The high free space loss and atmospheric absorption limits propagation to a few kilometers. Thus they are useful for densely packed communications networks such as personal area networks that improve spectrum utilization through frequency reuse.

Spectral efficiency comparison table - Link spectral efficiency 1 This can allow for much denser geographical frequency reuse that compensates for the lower link spectral efficiency, resulting in approximately the same capacity (the same number of simultaneous phone calls) over the same bandwidth, using the same number of base station transmitters

Spectral efficiency comparison table - System spectral efficiency or area spectral efficiency 1 :'Example 8:' In a cellular system based on frequency-division multiple access (FDMA) with a fixed channel allocation (FCA) cellplan using a frequency reuse factor of 4, each base station has access to 1/4 of the total available frequency spectrum

Spectral efficiency comparison table - System spectral efficiency or area spectral efficiency 1 Spread spectrum makes it possible to have as low a frequency reuse factor as 1, if each base station is divided into 3 cells by means of 3 directional sector antennas

Cell site - Channel reuse 1 To overcome this limitation, it is necessary to repeat and frequency reuse|reuse the same channels at different locations

DECT - Radio links 1 If frequency-hopping is avoided, each base station can provide up to 120 channels in the DECT spectrum before frequency reuse

Cellular networks - Frequency reuse 1 The key characteristic of a cellular network is the ability to re-use frequencies to increase both coverage and capacity. As described above, adjacent cells must use different frequencies, however there is no problem with two cells sufficiently far apart operating on the same frequency. The elements that determine frequency reuse are the reuse distance and the reuse factor.

Cellular networks - Frequency reuse 1 Recently also orthogonal frequency- division multiple access based systems such as 3GPP Long Term Evolution|LTE are being deployed with a frequency reuse of 1. Since such systems do not spread the signal across the frequency band,

Licensed spectrum - Governments and spectrum management 1 Unlike these, however, frequency reuse|RF is reusable

Frequency allocation 1 * Only the licensed user of that band may transmit: the licensing body may give the same frequency to several users as a form of frequency reuse if they cannot interfere because their coverage map areas never overlap.

Digital Audio Broadcasting - Use of frequency spectrum and transmitter sites 1 The frequency reuse factor for local programmes and multi-frequency broadcasting networks (Multi-frequency network|MFN) is typically 4 or 5, resulting in 1 / 4 / (0.26MHz) = 0.96 programmes/transmitter/MHz

Super high frequency - Propagation 1 Such high gain antennas allow frequency reuse by nearby transmitters

Super high frequency - Utilization 1 They are the lowest frequency band where radio waves can be directed in narrow beams by conveniently sized antennas so they do not interfere with nearby transmitters on the same frequency, allowing frequency reuse

Saorsat - Overview 1 The spot beam with frequency reuse means reception in most of Britain and continental Europe is not possible

Microwaves - Microwave uses 1 Microwaves are especially suitable for this use since they are more easily focused into narrower beams than radio waves, allowing frequency reuse; their comparatively higher frequencies allow broad Bandwidth (signal processing)|bandwidth and high data transmission rates, and antenna sizes are smaller than at lower frequencies because antenna size is inversely proportional to transmitted frequency

Spectrum allocation 1 * Only the licensed user of that band may transmit: the licensing body may give the same frequency or band to several users as a form of frequency reuse if they cannot interfere because their coverage map areas never overlap. Amateur radio frequency allocations also devoted only for licensed users with listen before talk contention-based protocol.

Radio resource management 1 RRM is especially important in systems limited by co-channel interference rather than by noise, for example cellular systems and broadcast networks homogeneously covering large areas, and wireless networks consisting of many adjacent Wireless access point|access points that may frequency reuse|reuse the same channel frequencies.

Radio resource management 1 In cellular networks, this means that the fractional frequency reuse in the GSM standard has been replaced by a universal frequency reuse in LTE (telecommunication)|LTE standard.

Radio resource management - Dynamic radio resource management 1 Dynamic RRM schemes adaptively adjust the radio network parameters to the traffic load, user positions, user mobility, quality of service requirements, base station density, etc. Dynamic RRM schemes are considered in the design of wireless systems, in view to minimize expensive manual cell planning and achieve tighter frequency reuse patterns, resulting in improved system spectral efficiency.

Radio resource management - Inter-cell radio resource management 1 Future networks like the LTE (telecommunication)|LTE standard (defined by 3GPP) are designed for a frequency reuse of one

Spectrum management - Governments and spectrum management 1 Unlike these, however, frequency reuse|RF is reusable.[ Radio spectrum as natural resource] The purpose of spectrum management is to mitigate radio spectrum pollution and maximize the benefit of usable radio spectrum.[ Application of the Public-Trust Doctrine and Principles of Natural Resource Management to Electromagnetic Spectrum]

Polarisation division multiple access 1 Each corresponding ground station antenna needs to be polarized in the same way as its counterpart in the satellite. This is generally accomplished by providing each participating ground station with an antenna that has dual polarization. The frequency band allocated to each antenna beam can be identical because the uplink signals are orthogonal in polarization. This technique allows frequency reuse.

Spectrum efficiency - System spectral efficiency or area spectral efficiency 1 :'Example 8:' In a cellular system based on frequency-division multiple access (FDMA) with a fixed channel allocation (FCA) cellplan using a frequency reuse factor of 1/4, each base station has access to 1/4 of the total available frequency spectrum

Tooway - Technology 1 Smaller beams allow more efficient use of satellite power on the forward link and improved G/T (Link budget|Gain-over- Temperature) on the return link. Smaller beams draw smaller cells on ground (beam footprint) which also permits more cells in a given service area, increasing frequency reuse.

Ultra Mobile Broadband - Features 1 **Dynamic fractional frequency reuse

Power control - Benefits 1 Even in FDMA systems such as GSM where each user in a cell uses a different frequency, interference is still present between different cells and reduces the amount of frequency reuse the network can support

Co-channel interference 1 The co-channel interference arises in the cellular mobile networks owing to this phenomenon of Cellular network|Frequency reuse

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