EMI Suppression Filters (EMC and Noise Suppression)LTE Noise Problems

What Is LTE?

The Long Term Evolution (LTE) is one of communication standards for next-generation mobile phones, which has evolved the high-speed data communication standard HSDPA for the mainstream 3G (third generation) mobile phone system W-CDMA at present.
The LTE specifications have been standardized by 3G (W-CDMA) Standardization Organization 3GPP (3rd Generation Partnership Project) as "3GPP Release 8."


The LTE allows high-speed data communication (reception: 100 Mbps or higher and transmission: 50 Mbps or higher). Since the frequency band is expanded up to 20 MHz, the logical maximum transmission rate is 326.4 Mbps in reception and 86.4 Mbps in transmission.
The data communication rate is higher than that of 3G/3.5G even at the same frequency band, which allows acceptance of a lot of users.
Furthermore, the LTE achieves low-delay transmission with a connection delay of 100 ms or less and a radio section transmission delay of 5 ms or less. Thus the LTE is suited for audio communication, moving picture distribution, and online games.

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Trends of LTE

Data communication volume of mobile phones is rapidly increasing at present due to dissemination of smart phones and mobile communication. Therefore, expansion of communication band (capacity) is a critical issue for communication carriers.
Because the LTE that allows high-speed data communication with low delay is superior in terms of the radio wave use efficiency, many of major communication carriers in the world have indicated a policy of adopting the LTE. The rapid dissemination of the LTE in the future is expected.

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LTE Technologies and Noise Suppression

A broad frequency range (700 MHz to 2.7 GHz) is adopted for the LTE and frequency bands are allocated to communication carriers in each country.
To enhance this frequency use efficiency, antenna technologies, including Multi Input Multi Output (MIMO) that allows transmission/reception with multiple antennas and Space Division Multiple Access (SDMA) that allows multiple access between base stations, have been introduced. Furthermore, Orthogonal Frequency Division Multiple Access (OFDMA) and Single Carrier Frequency Division Multiple Access (SC-FDMA) are used as multiplexing systems.
On the other hand, mobile terminals provided with a radio communication function have a problem of intra-system EMC (receiving sensitivity suppression caused by interference of internal noise with radio communication). Further noise suppression is essential to respond to high-speed communication technologies of the LTE.

Broad Frequency Bands

Noise must be suppressed in all frequency bands to be used for terminals to be sold in the world.

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Communication System Using Multiple Transmission/Reception Antennas

The LTE mobile phone system adopts the MIMO system having multiple antennas to allow high-speed communication.

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If noise generated in a mobile phone interferes with the antenna, the radio sensitivity lowers and the communication quality is degraded. Therefore, such interference must be suppressed by noise suppression. (Intra-system EMC)
Noise must be suppressed for all antennas because the LTE allows high-speed communication using multiple antennas.

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