Introducción al branding sensorial

When option

received UL and DL power will apply a random fading value for each landuse code. The random fading varies with each Monte Carlo iteration according to the a log- normal distribution configured in the

Random fading is applied to each individual UL and DL link between cells and mobile terminals, but not at all for fixed subscribers.

3.6.6

Rejecting Users on Resource Shortage

This option is selectable in the LTE bearer editor. It controls how overload situations are resolved in the LTE Analysis depending on the presence of guaranteed and non- guaranteed bit rate bearers.

Radio bearers with this option selected are considered by the LTE Analysis as lower priority bearers and are blocked first if the UL or DL capacity is overloaded in a cell, see figure below.

Use random fading is selected, the algorithm for calculation of Standard deviation.

Observe that this option is only valid for radio bearers with a guaranteed bit rate reported as “Rejected in UL” or “Rejected in DL” in the LTE Analysis Report. If there is a resource shortage in UL and/or DL for subscribers on GBR radio bearers (guaranteed bit rate larger than zero) and they cannot be served at this bit rate, their blocking reason is set to “GBR not reached” for UL and/or DL.

set to zero (non-GBR bearers). If a subscriber on such a bearer is blocked it will be

3.6.7

Number of Transmit Antennas in a Cell

The number of transmit antennas can be set in the cell editor of an LTE base station. In case a cell has two transmit antennas for transmit diversity or MIMO, the second transmission path creates a certain amount of DL interference in the network. When calculating the DL interference in the serving cell, this interference component is taken into consideration.

Observe that the number of transmit antennas and the selected transmission scheme also influence the choice of data rate mapping table for calculation of the achieved UL and DL data rates. The reason is the following: In case of transmit diversity there is a gain in achieved signal quality on the DL, which leads to higher achieved DL data rates. In case of MIMO transmission, separate transmission paths are available to the terminal in UL and DL. For instance, in the case of 2x2 MIMO there are two transmission paths and the theoretical DL capacity doubles.

However, for each additional antenna port a certain bandwidth is required for transmission of DL reference symbols, PDCCH information, SCH and BCH data. For each transmit antenna the cell will send separate reference symbols on the DL. In case of TX Diversity and MIMO DL transmission the terminal has to be able to distinguish between the reference symbols of the different antenna ports.

Therefore, there is a pre-defined position for the reference symbols depending on how many antennas are connected to a cell. The amount of RBs that is used for reference symbols is retrieved from the selected transmission scheme in the LTE cell and the amount of DL PDCCH symbols is defined by the settings in the LTE carrier mapping properties, see figure below.

The transmitter power is assumed to be the same irrespective of antenna technique, although the number of transmitters in a cell is doubled when using 2x2 MIMO or 2x2 Tx diversity, compared to 1x2 SIMO.

bearer-terminal combinations in the selected traffic demand mix. The average values over all Monte Carlo trials are reported. Data rates with and without MIMO are calculated. In contrast to the MIMO data rate gain plot, which compares 2x2 MIMO with 2x2 Tx diversity, this algorithm compares 2x2 MIMO with 1x2 SIMO. When a cell is reconfigured from SIMO to 2x2 MIMO transmission, the increased capacity due to using MIMO leads to a lower DL load on the cell as long as the offered traffic is constant. The reduced DL load leads to lower interference, hence better performance, also in the surrounding cells. This additional gain is however not taken into account in the analysis, hence the gain of using MIMO might in reality be even better than reported.

The more symbols that are required in each transmit path for DL control and reference symbols, the less Resource Blocks are available for data transmission. The number of antennas and the selected transmit scheme of the cell are taken into consideration when calculating the achievable UL and DL data rates.

3.6.8

Activity, Load and Utilization

Activity, Load and Utilization are fundamental concepts when simulating an LTE network. The definitions are outlined and illustrated below.

Activity

The

percentage of time that the cell is sending (DL activity) or receiving (UL activity). The maximum UL cell activity is one of the Admission Control Parameters. The calculated UL cell activity may be shown in a plot.

Load

The

sum can be illustrated as an area in the time-frequency domain.

The maximum DL and UL cell load are configured as Admission Control Parameters. DSCH becomes silent when there is no data to send to any user, but the Reference Symbols, Synchronization Channel and Broadcast Channel keeps sending.

Utilization

The LTE Analysis takes traffic demand mix and scale factor as input to calculate the load, limits it by the maximum cell Load, and presents the result as the

The utilization may be shown in UL and DL plots, and can be applied (fed back) to the cell load parameters.