WiMAX antennas, just like the antennas for car radio, cell phone, FM radio, or TV, are designed to optimize performance for a given application. The figure above illustrates the three main types of antennas used in WiMAX deployments. From top to bottom are an omni directional, sector and panel antenna each has a specific function. … Read more
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
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
Radio wave can be propagated from the transmitting antenna to the receiving antenna in many ways: perpendicular incidence wave or ground refraction wave, diffraction wave, troposphere reflection wave, ionosphere reflection wave, as shown in the diagram. As for radio wave, the most simple propagation mode between the transmitter and the receiver is free space propagation. … Read more
WiMAX is a coined term or acronym meaning worldwide interoperability for microwave access (WiMAX). What WiMAX is however at its heart is a standards initiative. Its purpose is to ensure that the broadband wireless radios manufactured for customer use interoperate from vendor to vendor. WiMAX is a family of wireless broadband communication standards that are … Read more
In addition to 3G, Wi-Fi based-systems may be used to provide broadband wireless. Wi-Fi is based on the IEEE 802.11 family of standards and is primarily a local area networking (LAN) technology designed to provide in-building broadband coverage. Wi-Fi is the name of a wireless network technology that uses radio waves to provide high-speed wireless … Read more
The Logical Channel is used in time multiplex in a physical channel, which is categorized according to the types of messages transmitted in the physical channel. Different logical channels are used in transmission of different types of information between BS and MS, such as the signaling or traffic data. In GSM system, five different types … Read more
RRC uses the following states: RRC_Idle: •The UE is not connected. There is no radio link. •The network knows that the UE is present on the network and is able to reach it in case of incoming call. •The UE switches in idle mode when it is connected and there is no traffic to save … Read more
Broadcast Channels (BCH) Frequency correction channel (FCCH) the “lighthouse” of a BTS Synchronization channel (SCH) PLMN/base identifier of a BTS plus synchronization information (frame number) Broadcast control channel (BCCH) to transmit system information 1-4, 7-8 (differs in GSM 900, GSM 1800, and PCS 1900) CBCH and CCCH CBCH (Cell Broadcast Channel) transmits cell broadcast messages … Read more
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