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The detailed difference between 4G industrial router...   4G industrial router and 4G DTU both realize the wireless network data transmission function, and the differences between them are mainly from the use method, appearance interface and application environment, etc. Today, we will introduce some differences between 4G router and 4G DTU.   Different methods...

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Application analysis of iot sensing technology   The Internet of things (iot) is widely used in the integration of networks through intelligent perception, recognition technology, pervasive computing and other communication perception technologies. The iot is understood as "Internet connected by things". The Internet of things (iot) connects all objects with...

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What is a single/dual frequency wireless 4G router 1. Introduction to "single frequency" router The single-frequency router only works in the 2.4ghz band, which is generally supported by wireless terminals. However, the 2.4ghz band has large interference, which may affect the wireless rate and stability.   2. Introduction to "dual-frequency" router Dual-frequency...

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Wireless communication DTU features Data Transfer unit (DTU) is a wireless terminal device specially used to convert serial Data into IP Data or convert IP Data into serial Data for transmission through wireless communication network.   DTU advantages: Rapid and flexible network, short construction cycle, low cost; Wide network coverage; Good...

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The advantage of using wireless data transmission module... Data transmission can be simply divided into two major types: wired (including the installation of optical cables, cables or leased telecommunication lines) and wireless (including the establishment of dedicated wireless data transmission system or the borrowing of CDPD, GSM, CDMA and other public network information platforms).     In...

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Difference in between LTE FDD and TDD?

Category : 其他

What is difference in between LTE FDD & TDD?

In both LTE FDD and LTE TDD, the transmitted signal is organized into subframes of 1 millisecond (ms) duration and 10 subframes constitute a radio frame. Each subframe normally consists of 14 OFDM symbols (12 OFDM symbols in case of the so-called Extended Cyclic Prefi).

Although the frame structure is, in most respects, the same for LTE FDD and LTE TDD, there are some differences between the two, most notably the use of special subframes in TDD. Another difference is the other subframes are allocated either for uplink transmission or for downlink transmission.

In case of FDD operation, there are two carrier frequencies, one for uplink transmission (fUL) and one for downlink transmission (fDL). During each frame, there are consequently 10 uplink subframes and 10 downlink subframes and uplink and downlink transmission can occur simultaneously within a cell.

In case of TDD operation, there is only one single carrier frequency and uplink and downlink transmissions in the cell are always separated in time. As the same carrier frequency is used for uplink and downlink transmission, both the base station and the mobile terminals must switch from transmission to reception and vice versa. Thus, as a subframe is either an uplink subframe or a downlink subframe, the number of subframes per radio frame in each direction is less than 10.

Check further info at www.e-lins.com for 4G LTE info.

TDD LTE and FDD LTE

Category : 技术相关

As we know, the LTE mainly covers two types, which are TDD and FDD.  Let’s talk something about TDD LTE and FDD LTE’s Advantages / disadvantages of for cellular communications.

There are a number of the advantages and disadvantages of TDD and FDD that are of particular interest to mobile or cellular telecommunications operators. These are naturally reflected into LTE.

COMPARISON OF TDD LTE AND FDD LTE DUPLEX FORMATS
PARAMETER TDD LTE FDD LTE
Channel reciprocity Channel propagation is the same in both directions which enables transmit and receive to use on set of parameters Channel characteristics different in both directions as a result of the use of different frequencies
Paired spectrum Does not require paired spectrum as both transmit and receive occur on the same channel Requires paired spectrum with sufficient frequency separation to allow simultaneous transmission and reception
Hardware cost Lower cost as no diplexer is needed to isolate the transmitter and receiver. As cost of the UEs is of major importance because of the vast numbers that are produced, this is a key aspect. Diplexer is needed and cost is higher.
UL / DL asymmetry It is possible to dynamically change the UL and DL capacity ratio to match demand UL / DL capacity determined by frequency allocation set out by the regulatory authorities. It is therefore not possible to make dynamic changes to match capacity. Regulatory changes would normally be required and capacity is normally allocated so that it is the same in either direction.
Guard period / guard band Guard period required to ensure uplink and downlink transmissions do not clash. Large guard period will limit capacity. Larger guard period normally required if distances are increased to accommodate larger propagation times. Guard band required to provide sufficient isolation between uplink and downlink. Large guard band does not impact capacity.
Cross slot interference Base stations need to be synchronised with respect to the uplink and downlink transmission times. If neighbouring base stations use different uplink and downlink assignments and share the same channel, then interference may occur between cells. Not applicable
Discontinuous transmission Discontinuous transmission is required to allow both uplink and downlink transmissions. This can degrade the performance of the RF power amplifier in the transmitter. Continuous transmission is required.