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 center frequencies must be spaced. In fact there is a trade-off between minimizing interference between different carriers and using the total bandwidth efficiently. In other … Read more
RF engineering is a trade off between: required radio spectrum (bandwidth), speed of data transmission (bit rates) and complexity of implementation. The pulse form used to modulate complex data symbols to the radio carrier frequency is the major element of this story. Over the years several pulse forms and their associated pulse shaping filters have … Read more
Spreading consists of 2 steps: Channelization operation, which transforms data symbols into chips Scrambling operation is applied to the spreading signal Spreading means increasing the bandwidth of the signal beyond the bandwidth normally required to accommodate the information. The spreading process in UTRAN consists of two separate operations: channelization and scrambling. The first operation is … Read more
How Many OFDMA Parameter for LTE? Which is OFDMA Parameter for LTE ? The width of a Sub-carrier is 15 kHz whatever the bandwidth The bandwidths are: 1.4, 3, 5, 10, 15 and 20 MHz Note that in LA1.1, only 5, 10 MHz are implemented The symbol duration is always the same whatever the bandwidth … Read more
How OFDMA Transmitter in LTE ? In the downlink, OFDM is selected to efficiently meet E-UTRA performance requirements. With OFDM, it is straightforward to exploit frequency selectivity of the multi-path channel with lowcomplexity receivers. This allows frequency selective in addition to frequency diverse scheduling and one cell reuse of available bandwidth. Furthermore, due to its … Read more
SC-FDMA utilizes single carrier modulation, DFT-spread orthogonal frequency multiplexing, and frequency domain equalization. LTE uses OFDMA on the DL. It allocates DL bandwidth to the user based on resource blocks, rather than individual subcarriers. When the signal is a combination of subcarriers, high amplitude power peaks can occur. The base stations power amplifiers are designed … Read more
Spectrum efficiency DL : 3-4 times UL : 2-3 times Frequency Spectrum Scalable bandwidth : 1.4, 3, 5, 10, 15, 20MHz To cover all frequencies of IMT-2000: 450 MHz to 2.6 GHz Peak data rate DL : > 100Mb/s for 20MHz spectrum allocation UL : > 50Mb/s for 20MHz spectrum allocation Latency C-plane : < … Read more
IMS means IP Multimedia Subsystem is an essential part of the all-IP UMTS architecture and Relevant for WiMAX for the same usage and also for WiMAX to UMTS Interworking. This is part of the WiMAX Forum architecture. IP Multimedia Subsystem (IMS) is a Service Delivery Architecture and standardized architecture to provide Internet Protocol (IP)-based mobile … Read more
Orthogonal frequency division multiple access (OFDMA): Mobile WiMAX uses OFDM as a multiple-access technique, whereby different users can be allocated different subsets of the OFDM tones. As discussed in detail in Chapter 6, OFDMA facilitates the exploitation of frequency diversity and multiuser diversity to significantly improve the system capacity. Flexible and dynamic per user resource … Read more
Here I write LTE network first step. For LTE planning it is important to know what available spectrum bandwidth to operator is and what actual frequency band allocation. Understanding Operator Spectrum Bandwidth Availability The purpose of detail planning is to determine a solid radio network design for possible deployment so radio engineer should not be … Read more