Passive Distributed Antenna Systems in 3G Various internal antenna solution can meet the different needs of the deployment. DAS solution distributes a plurality of antenna nodes throughout the coverage area. Each antenna assembly can transmit and receive signals 3G. The uplink signals from all the antenna units are collected in a central point, the point … Read more
Spatial multiplexing and Receive Diversity in Wimax Spatial multiplexing WiMAX also supports spatial multiplexing, where multiple independent streams are transmitted across multiple antennas. If the receiver also has multiple antennas, the streams can be separated out using space-time processing. Instead of increasing diversity, multiple antennas in this case are used to increase the data rate … Read more
Advanced Antenna Systems,Transmit diversity and Beamforming in Wimax Advanced Antenna Systems The WiMAX standard provides extensive support for implementing advanced multiantenna solutions to improve system performance. Significant gains in overall system capacity and spectral efficiency can be achieved by deploying the optional advanced antenna systems (AAS) defined in WiMAX. AAS includes support for a variety … Read more
Uplink data transmission in LTE The mapping of transport channels and UL control information (UCI) to physical channels is a task of the physical layer (PHY). Furthermore reference signals are provided by the physical layer which do not transfer any higher layer information. Logical channel mapping is provided by the MAC layer. Physical channel for … Read more
What is SC-FDMA and how it works in LTE? One of the major drawbacks of an OFDMA system is, that the transformation of a complex symbol mapped sequence (e.g. BPSK, QPSK, etc.) onto a small set of subcarriers produces time sequences that have high PAPR (Peak-to-Average Power Ratio). PAPR is the ratio between the maximum … Read more
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 similar to the WCDMA protocol stack of UMTS. The protocol stack defines three layers: the physical layer (layer 1), data … Read more
Physical Channel Types of LTE The physical layer uses resource blocks to transmit binary coded information in QPKS, 16QAM or 64QAM or OOK modulation form. Physical channels determine how data is processed and then mapped via dynamical scheduling onto resource blocks. Thus physical channels also in EUTRAN represent the available physical resources. Like transport channels, … Read more
Layer and channel relationship in LTE The radio interface is composed of different layers in order to set up, reconfigure and release the radio bearer services. The protocol layer is composed of physical layer (layer 1), data link layer (layer2), and the network layer (layer3). In the E-UTRAN layer 2 is divided into two sub-layers: … Read more
Uplink Power Control Calculation in LTE Transmit power of PUSCH in subframe i is defined by PPUSCH (i) = min{PMAX,10 log10 (MPUSCH (i)) + PO_PUSCH ( j) +α ( j) ⋅ PL + ΔTF (i) + f (i)} [dBm] Pmax: max. allowed power, MPUSCH: number of scheduled RBs, PL: pathless [dB]. ΔTF (i) = 10 … Read more
LTE Layer 2 user plane protocol stack in detail LTE user Layer 2 Protocol stack-the plan is composed of three substrates, as shown in the figure. Packet layer packet data convergence Protocol (PDCP) : this layer processes messages resource control (RRC) in the control plan and packages of Internet Protocol (IP) addresses in the user’s … Read more