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WiMAX versus 3G and Wi-Fi

How does WiMAX compare with the existing and emerging capabilities of 3G and Wi-Fi? The throughput capabilities of WiMAX depend on the channel bandwidth used. Unlike 3G systems, which have a fixed channel bandwidth, WiMAX defines a selectable channel bandwidth from 1.25MHz to 20MHz, which allows for a very flexible deployment. When deployed using the … Read more

Types of Power Control in CDMA

Reverse power control Open loop power control Closed loop power control Inner loop power control:  800 Hz Outer loop power control Forward power control Message transmission mode: threshold transmission periodic transmission Closed loop power control    Reverse open loop power control means that based on the detected signals from a base station, a mobile station … Read more

Long Code & Short Code In CDMA

The long code is a PN sequence with period of 242-1chips The functions of a long code: Scramble the forward CDMA channel Control the insertion of power control bit Spread the information on the reverse CDMA channel to identify the mobile stations       In a reverse direction, different long codes are used for the information … Read more

Interleaving in CDMA

It can be seen from the figure that the data are read row by row into an interleaver at the transmit end,read column by column out (this process is called interleaving) and propagated after other modulation process. Then, the data enter the interleaver at the receive end row by row and are read out column … Read more

India’s Supreme Court Rejects Appeals Over Confiscated GSM Licenses

India’s Supreme Court has rejected petitions to review its decision to void all 122 of the controversial GSM licenses that were awarded in 2008.   Seven mobile networks affected by the license cancellation including Videocon, STel, Idea Cellular, Tata Teleservices, Unitech Wireless, Sistema Shyam and Etisalat DB had filed separate petitions. The court declined the … Read more

How Synchronization Channel Works in LTE?

After the power on, the UE knows:  the UE category and capability. the preferred PLMN. the carriers. The UE needs to know: The frame synchronization to be able to decode the DL radio frame. The cell parameters to be able request a connection. The UE can use: The PSS: Primary Synchronization Signal. The SSS: Secondary … Read more

Random Access Procedure in LTE

When the UE has obtained system information, it has to request an RRCconnection. Like it has no dedicated resources, the UE requests the connection using the Random Access Procedure using common uplink resources.  At the end of the procedure, the UE is RRC connected UE and eNodeB are able to exchange data using dedicated radio … Read more

Step of RRC Connection Setup in LTE

When the UE is powered up, it has to be RRC connected to be able to exchange data and signaling with the network. After the RRC connection, the Initial network attach allows to establish all the bearers to carry the data from the UE to the gateway. After the RRC connection, Signaling Radio Bearers (SRBs) … Read more

System information & DL-SCH data in LTE

System information 1920 bits or 1728 bits are to be transmitted for normal or extended CP resp.. The PBCH is transmitted every 40 ms. The bit scrambling depends on the cell id and is starting in radio frames 0, 4, 8 … . PBCH uses QPSK. I.e. 960 (864) symbols need to be allocated. Mapping … Read more

How Time structure in LTE?

EUTRAN OFDM symbols have a basic duration of 66.667 ?s. This means up to 2048 complex samples per OFDM symbol in time domain representation. A cyclic prefix is pretended to the symbol. The size of the cyclic prefix can be chosen from three options: Normal prefix for 15 kHz: This is the standard option. It … Read more