Entendiendo la diferencia entre FDD vs TDD en sistema de microondas
- March 23, 2023
- FDD, high-capacity bandwidth, Microwave Capacity, TDD, wisp
Comprender los sistemas de microondas FDD vs. TDD –
Finalmente, es hora de descubrir el misterio entre FDD y TDD, específicamente la importancia de FDD como elemento clave en el rendimiento de la red.
FDD significa duplexación por división de frecuencia y TDD significa duplexación por división de tiempo. Tanto FDD como TDD son dos técnicas de uso del espectro, ambas formas de duplexación, utilizadas en enlaces de banda ancha inalámbricos fijos o móviles. Es esencial para estos enlaces que la transmisión pueda ocurrir en ambas direcciones simultáneamente para que los datos puedan fluir en el enlace descendente (DL) y en el enlace ascendente (UL) al mismo tiempo sin interrupciones.
Understanding FDD vs. TDD Microwave Systems
- March 22, 2023
- FDD, high-capacity bandwidth, Microwave Capacity, TDD, wisp
Don’t Get Burned with Half-Duplex Capacity Claims around FDD vs. TDD –
It is finally time to uncover the mystery between FDD vs. TDD, specifically the importance of FDD as a key element in network performance.
FDD stands for Frequency Division Duplex, and TDD stands for Time Division Duplex. Both FDD and TDD are two spectrum usage techniques, both forms of duplex, used in mobile or fixed wireless broadband links. It is essential to these links that transmission can occur in both directions simultaneously so that data can flow downlink (DL) and uplink (UL) at the same time without any noticeable interruptions.
TDD or FDD Wireless: That is the Question!
- June 10, 2011
- 3GPP Long Term Evolution, Bandplan, CEPT, Duplex (telecommunications), FDD, Frequency Division Duplex, Ian Marshall, Ofcom, Regulatory Manager, Spectrum auction, TDD, Time Division Duplex
TDD, or Time Division Duplex, where a single radio channel is used to send and receive data, has been a common technique employed in unlicensed microwave transmission bands, such as 2.4 and 5.8GHz. The advantage of TDD is a simplified and lower cost design, often based upon 802.11 standards. In contrast, FDD, or Frequency Division Duplex, where data is transmitted in one frequency channel and received in another (separated by anywhere from less than 100 to more than 1,000 MHz) has been the staple of licensed frequency bands between 2 and 38 GHz worldwide.
Now, a number of the CEPT recommendations for the new point to point bands over 40GHz contain provisions for TDD operation. TDD is accommodated either as an alternative band plan or a mixed TDD/FDD band plan, in addition to the more common FDD band plan. However, CEPT recommendations are only just that—recommendations. How these bands will be implemented in each country will be determined by the individual national regulatory authority.
Recently, we asked a number of European national regulators about if and how they would introduce TDD operation in these new bands. The general response was that they were not opposed to the introduction of TDD in principle, and that such operation would have to be worked into existing or revised band plans. One complication raised was that spectrum would have to be reserved for guard bands between TDD and FDD segments within the same band. Regulators usually try to avoid having to waste valuable spectrum in this way. Also, once a band plan is established and the spectrum allocated to users, efforts to introduce TDD operation at a later date is extremely difficult.
Some regulators have already issued new national band plans at 42GHz and above, and to date none of these allow for TDD operation. Furthermore, for countries that have allocated new bands through spectrum auction, there we see the usual FDD style symmetric band approach.
Despite the appeal of TDD operation from a cost perspective, early indications are that although provision for TDD operation is being made in these higher bands, practical complications and concerns over maximizing the use of new bands may prevent its widespread introduction.
What are your thoughts on using TDD more in national band plans? Leave a comment, if you’d please.
Ian Marshall
Regulatory Manager, Aviat Networks
Related articles
- Time Division Duplex (TDD) vs Frequency Division Duplex (FDD) in Wireless Backhauls (ezinearticles.com)
- Ofcom publishes Real Wireless study as part of UK’s 4G spectrum auction proposals (realwireless.wordpress.com)
- Behind the Ofcom plan: four LTE networks, and not a lot else (go.theregister.com)
- What is Long Term Evolution? (brighthub.com)
- Our report on 2.6 GHz technical licence conditions published by Ofcom (realwireless.wordpress.com)