Difference Between OFDM and FDM in LTE

FDM in LTE Conventional multi-carrier operation as it is used for FDM works simply by selecting a number of center frequencies – one for each carrier to be used. The…

How Sub-Carrier Allocation in Wimax?

Sub-Carrier Allocation Mode 1 DL PUSC – Downlink partial Usage Sub-Channels The downlink PUSC replacement zone is unique, that must exist in the frame structure specified by the protocols. DL…

How QPSK & BPSK Modulation in WCDMA?

A data-modulation scheme defines how the data bits are mixed with the carrier signal, which is always a sine wave. There are three basic ways to modulate a carrier signal…

How Many Broadcast Channels & what’s it work in GSM ?

BCCH(Broadcast Control Channels) Downlink Only. Broadcast information of the serving cell (System Information). Transmitted on timeslot zero of BCCH carrier. Read only by idle mobile at least once every 30…

LTE SC-FDMA and LTE Uplink

Introduction to SC-FDMA and uplink frame structure Marriage of single carrier transmission and FDMA Uplink SC-FDMA tranmsit and receive chains Peak to Average Power Ratio (PAPR) comparison with SC-FDMA and…

Physical Combination of Logical Channel in GSM

As shown above, CCCH=PCH+RACH+AGCH; downlink CCCH=PCH+AGCH; and uplink CCCH=RACH. In the above combinations, combination 3 and 4 must be allocated to slot 0 of the BCCH carrier configured for the…

Ways to transmit training symbols: preamble or pilot tones in Wimax

There are two ways to transmit training symbols: preamble or pilot tones. Preambles entail sending a certain number of training symbols prior to the user data symbols. In the case…

Radio Protocol Architecture in LTE

The EUTRAN radio protocol model specifies the protocols terminated between UE and eNB. The protocol stack follows the standard guidelines for radio protocol architectures (ITU-R M1035) and is thus quite…

How to LTE Radio Air Interface?

The state-of-the-art design of the LTE air interface is characterised by OFDMA (DL) and SC-FDMA (UL) together with MIMO. The downlink modulation is based on OFDMA (Orthogonal Frequency Division Multiple…