π/4 DQPSK
E736616
π/4 DQPSK is a digital phase modulation scheme that encodes data by shifting the carrier phase in quarter-pi increments to improve spectral efficiency and reduce signal distortion in wireless communication systems.
Statements (50)
| Predicate | Object |
|---|---|
| instanceOf |
differential phase shift keying scheme
ⓘ
digital modulation scheme ⓘ phase modulation scheme ⓘ |
| advantage |
better suited to nonlinear RF power amplifiers
ⓘ
good compromise between complexity and performance ⓘ more constant envelope than conventional QPSK ⓘ reduced adjacent channel interference compared to some other schemes ⓘ supports coherent and differential detection ⓘ |
| applicationDomain |
digital cellular networks
ⓘ
mobile radio ⓘ wireless communications ⓘ |
| benefitOfTransitionConstraint |
reduces intersymbol interference in nonlinear channels
ⓘ
reduces spectral sidelobes ⓘ |
| bitPerSymbol | 2 bits per symbol ⓘ |
| carrierPhaseAmbiguityTolerance | tolerant due to differential encoding ⓘ |
| channelType | fading wireless channels ⓘ |
| constellationRotation | alternates between two QPSK constellations rotated by 45 degrees ⓘ |
| constellationType | offset QPSK constellation ⓘ |
| dataEncoding | information encoded in phase difference between successive symbols ⓘ |
| detectionMethod |
coherent detection with carrier recovery
ⓘ
differential detection ⓘ |
| envelopeProperty | quasi-constant envelope ⓘ |
| errorPerformance | similar to QPSK under AWGN ⓘ |
| fullName | pi over four differential quadrature phase shift keying NERFINISHED ⓘ |
| goal |
improve spectral efficiency
ⓘ
reduce envelope variations ⓘ reduce signal distortion ⓘ |
| implementationComplexity | moderate ⓘ |
| modulationIndex | phase changes restricted to ±π/4 and ±3π/4 ⓘ |
| phaseIncrement |
45 degrees
ⓘ
π/4 radians ⓘ |
| relatedTo |
DQPSK
NERFINISHED
ⓘ
OQPSK ⓘ QPSK NERFINISHED ⓘ |
| requiresCarrierRecovery | not strictly required for differential detection ⓘ |
| robustness | more robust to nonlinear distortion than standard QPSK ⓘ |
| spectralEfficiency | similar to QPSK ⓘ |
| standardizationContext | used in North American digital cellular standards ⓘ |
| symbolMapping | differential phase changes represent symbol transitions ⓘ |
| symbolTransitionConstraint | avoids 180-degree phase transitions ⓘ |
| typicalFilter | root raised cosine pulse shaping ⓘ |
| usedIn |
2G mobile systems
ⓘ
IS-136 standard NERFINISHED ⓘ IS-54 standard NERFINISHED ⓘ cellular communication systems ⓘ some satellite communication links ⓘ some wireless local loop systems ⓘ |
| usesDifferentialEncoding | true ⓘ |
| usesModulationType | phase shift keying ⓘ |
| usesQuadratureComponents | true ⓘ |
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.
subject surface form:
iDEN