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WHAT IS THE STRUCTURE OF THE DOWNLINK PHYSICAL RESOURCE IN LTE ?

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LTE downlink transmission is based on Orthogonal Frequency Division Multiplex (OFDM). Radio frames in LTE are transmitted in both time and frequency domain. The basic LTE downlink physical resource can thus be seen as a time-frequency grid as illustrated in Figure below. Resource Element Each resource element corresponds to one frequency sub-carrier during one OFDM […]

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WHAT ARE THE PHYSICAL CHANNELS AND SIGNALS USED IN LTE?

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The following physical channels and physical signals are defined in LTE: PHYSICAL CHANNELS Physical Downlink Shared Channel (PDSCH) and Physical Uplink Shared Channel (PUSCH), used for transmission of the DL-SCH and UL-SCH transport channels, respectively. Physical Control Format Indicator Channel (PCFICH), Physical Downlink Control Channel (PDCCH) and Physical Hybrid ARQ Indicator Channel (PHICH), used for […]

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WHAT IS THE MAPPING BETWEEN LOGICAL CHANNEL , TRANSPORT CHANNELS AND PHYSICAL CHANNELS

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The mapping between logical, transport and physical channels is shown vividly in the picture below.

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WHAT AVAILABLE LOGICAL CHANNELS EXIST IN LTE ?

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Logical channels carry the type of information. In this regard, logical channels can be divided into control channels and traffic channels. The control channels are used for transfer of control plane information and the traffic channels are used for the transfer of user plane information. The logical channels in LTE Air Interface are shown in […]

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WHAT ARE THE AVAILABLE TRANSPORT CHANNELS IN LTE?

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In LTE an effort has been made to keep a low number of transport channels to avoid unnecessary switching between different channel types, which are found to be time consuming in other technologies such as WCDMA. In fact, there is currently only one transport channel in downlink and one in uplink carrying user data. Therefore, channel switching […]

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