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As an example of how the 2D spreading on VSF-OFCDM works, if you take the first data symbol, d 0, and a spreading factor in the time domain, SF time, of length 4, and a spreading factor in the frequency domain, SF frequency of 2, then the data symbol, d 0, will be multiplied by the length-2 frequency-domain PN codes and placed on subcarriers 0 ...
[clarification needed] The technology of CDMA was used in 1957, when the young military radio engineer Leonid Kupriyanovich in Moscow made an experimental model of a wearable automatic mobile phone, called LK-1 by him, with a base station. [8] LK-1 has a weight of 3 kg, 20–30 km operating distance, and 20–30 hours of battery life.
The time-division multiple access (TDMA) channel access scheme is based on the time-division multiplexing (TDM) scheme. TDMA provides different time slots to different transmitters in a cyclically repetitive frame structure. For example, node 1 may use time slot 1, node 2 time slot 2, etc. until the last transmitter when it starts over.
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 ...
In digital communications, a chip is a pulse of a direct-sequence spread spectrum (DSSS) code, such as a pseudo-random noise (PN) code sequence used in direct-sequence code-division multiple access (CDMA) channel access techniques.
cdmaOne network structure. The IS-95 standards describe an air interface, [1] a set of protocols used between mobile units and the network. IS-95 is widely described as a three-layer stack, where L1 corresponds to the physical layer, L2 refers to the Media Access Control (MAC) and Link-Access Control (LAC) sublayers, and L3 to the call-processing state machine.
TDS – Technical Data Sheet Telcordia. TIA – Telecommunications Industry Association TIA-2000. TIA-41 – Cellular Radio-Telecommunications Intersystem Operations TIA-856. TIA-878. TLDN – Temporary Local Directory Number TMSI – Temporary Mobile Station Identity Triple DES – Triple Data Encryption Standard Trading Partner Agreements
It uses advanced multiplexing techniques including code-division multiple access (CDMA) as well as time-division multiplexing (TDM) to maximize throughput. It is a part of the CDMA2000 family of standards and has been adopted by many mobile phone service providers around the world particularly those previously employing CDMA networks.