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GSM RF Optimization Step by Step

Here I write about GSM RF Optimization Step by Step and how to find KPI degradation and its solution. The RF network optimization process can be categorized by the following steps: Problem analysis Analyzing performance retrieved from tool reports and statistics for the worst performing BSCs and/or Sites Viewing ARQ reports for BSC/Site performance trends … Read more

How Modulation-QPSK in CDMA ?

     In an actual application, the system implements the modulation in this way:  as shown above, I and Q channel sequences in the figure represent two channels of cyclic PN short code sequences.  The cyclic period of each channel of PN short codes is 215. For different sectors, there are different starting locations of I … Read more

Ranging in Wimax

The initial range is the process of estimating the distance or propagation time between a transmitter and a receiver. Area information can be used to assist in setting operating parameters for the transmitter and receiver. Since each MS has a unique distance from the base station, it is critical in the uplink to synchronize the … Read more

Forward Traffic Channel of CDMA

Forward Traffic Channel is used to Transmit Data and Signaling Information. Symbol repetition makes symbol streams at different rates adapted to those at the rate of 19.2k. The original symbol stream at  the rate of 19.2Kbps will not be repeated, 9.6Kbps symbol stream will be repeated once, 4.8Kbps symbol stream will be repeated twice…. Then, … Read more

Downlink Power control in LTE

The eNodeB determines the downlink transmit energy per resource element (lte epre). Downlink cell-specific reference-signal (RS) lte epre is constant across the downlink system bandwidth and constant across all subframes until different cell-specific RS power information is received. The downlink RS lte epre is given by the parameter Reference-signal-power provided by higher layers. In cases 16QAM, 64QAM, … Read more

What is AMC & its Algorithm in LTE

The effective Eb/No and hence the spectral efficiency depend on BLER. However there are QoS requirements which also have to be considered. Taking both into account leads to a target BLER. AMC is in use in order to tune BLER so that the target value is reached. Therefore when channel conditions change modulation and/or coding … Read more

What is 3G? or WCDMA?

3G is new upgraded cdma technology, in simple word its Wide band Code Devision Multiple Access Technology (WCDMA). This is first technology in which video call possible means voice and data simultaneously transmitted and received between mobile or data card and BTS – Base Transmission Station. WCDMA Having Below Characterictics Support two basic modes: FDD and … Read more

LTE Downlink Logical Channel

Paging Control Channel(PCCH) A downlink channel that transfers paging information and system information change notifications. This channel isused for paging when the network does not know the location cell of the UE Broadcast Control Channel (BCCH) Provides system information to all mobile terminals connected to the eNodeB. A downlink channel for broadcasting system control information … Read more

Specifications of WCDMA

Channel Bandwidth  5 MHz Duplex Mode  FDD and TDD Downlink RF Channel Structure  Direct Spread (DS) Chip Rate  3.84 Mcps Frame Length  10 ms Spreading Modulation  Balanced QPSK (downlink) Dual-channel QPSK (uplink) Complex spreading circuit Coherent detection  • User dedicated time multiplexed pilot (downlink and uplink) • common pilot in downlink Channel Multiplexing in Downlink  … Read more

Main Characterictics of WCDMA

Support two basic modes: FDD and TDD modes High chip rate (3.84 Mcps) and data rates (up to 2 Mbps) Employs coherent detection on uplink and downlink based on the use of pilot symbols Inter-cell asynchronous operation Fast adaptive power control in the downlink based on SIR Provision of multirate services Packet data Seamless inter-frequency … Read more