Time-division multiple access: Difference between revisions

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=== 3G systems ===

{{Expand section|date=November 2014}}

AlthoughIn mostthe majorcontext of 3G systems, arethe primarilyintegration basedof uponTime-Division Multiple Access (TDMA) with [[Code-division multiple access|Code-Division Multiple Access]] (CDMA) and Time-Division Duplexing (TDD) in the [[UMTS|Universal Mobile Telecommunications System]], (UMTS) represents a sophisticated approach to optimizing spectrum efficiency and network performance.<ref>{{Cite book|url=https://books.google.com/books?id=zLz-CwAAQBAJ&q=3G+systems+are+primarily+based+upon+CDMA&pg=PT24|title=Principles of Modern Wireless Communication Systems|last=Jagannatham|first=Aditya K.|publisher=McGraw-Hill Education|year=2016|isbn=9789339220037}}</ref> time-division duplexing (TDD), packet scheduling (dynamic TDMA) and packet-oriented multiple access schemes are available in 3G form, combined with CDMA to take advantage of the benefits of both technologies.

UTRA-FDD (Frequency Division Duplex) employs CDMA and FDD, where separate [[Spectral band|frequency bands]] are allocated for uplink and downlink transmissions. This separation minimizes interference and allows for continuous data transmission in both directions, making it suitable for environments with balanced traffic loads.<ref name=":0">{{Cite journal |title=3G mobile systems |url=https://link.springer.com/content/pdf/10.1007/0-306-47795-5_3.pdf |format=pdf |journal=[[Springer Nature]] |language=English |publisher=Springer, Boston, MA |page=45–89 |doi=10.1007/0-306-47795-5_3 |isbn=978-0-306-47795-9 |url-access=subscription}}</ref>

While the most popular form of the [[UMTS]] 3G system uses CDMA and [[frequency-division duplex]]ing (FDD) instead of TDMA, TDMA is combined with CDMA and time-division duplexing in two standard UMTS UTRA.

UTRA-TDD (Time Division Duplex), on the other hand, combines CDMA with TDMA and TDD. In this scheme, the same frequency band is used for both uplink and downlink, but at different times. This time-based separation is particularly advantageous in scenarios with asymmetric traffic loads, where the data rates for uplink and downlink differ significantly. By dynamically allocating time slots based on demand, UTRA-TDD can efficiently manage varying traffic patterns and enhance overall network capacity.<ref name=":0" /><ref>{{Cite web |title=ETSI TS 136 214 V14.3.0 (2017-10) |url=https://www.etsi.org/deliver/etsi_ts/136200_136299/136214/14.03.00_60/ts_136214v140300p.pdf}}</ref>

The combination of these technologies in UMTS allows for more flexible and efficient use of the available spectrum, catering to diverse user demands and improving the adaptability of 3G networks to different operational environments.<ref name=":0" />

== In wired networks ==