03.oep100310 lte radio network coverage dimensioning isuee 1.10.pdf

8/9/2019 03.OEP100310 LTE Radio Network Coverage Dimensioning ISUEE 1.10.pdf

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LTE Radio Network Coverage Dimensioning

Confidential Information of Huawei. No Spreading Without Permission



Before dimensioning some link budget parameters need to be prepared such as

penetration loss, propagation model, fading margin and interference margin







Before a network planning, we should firstly decide the planning targets, Which are

important inputs for the planning

The target service is the data service normally, the target quality of the data service is

judged by the cell edge throughput. This throughput requirements are normally different in

different target area, such as urban and rural.

The coverage probability is according to the network deployment strategy, for different

region ,such as dense urban and rural, we may apply different coverage probability.

Target load affects not only the cell capacity, but also the coverage, since in different load

conditions, the interference at of cell border is different also.

Before planning, we should collect as much information as possible, such as to confirm ifthe indoor areas’ coverage is required, if TMA is used or not ...



The type of area will affect the pass loss during the link budget, including

Channel mode Indoor penetration loss

Standard deviation of shadow fading margin

Path loss factor

Morphologies determines the propagation model formula using in cell radius calculation,

as well as other parameters such as eNodeB antenna height and penetration loss

Channel model has effect on the demodulation threshold and lead to difference cell radius

ETU: Extended Typical Urban model

EVA: Extended Vehicular A model





Radio Network Dimensioning is a simplified analysis for radio network.

Dimensioning provides the first and most rapid evaluation of the network element numberas well as the associated capacity of those elements. The target of dimensioning phase is

to estimate the required site density and site configurations for the area of interest.

Dimensioning activities include radio link budget and coverage analysis, capacity evaluation

and final estimation of the amount of eNodeB hardware, cell average throughput and cell

edge throughput.

Objective:

To obtain the network scale ( approximate eNodeB number and configuration)

Method: Select a proper propagation model, traffic model and subscriber distribution, and

then estimate the eNodeB number, coverage radius, cell throughput, cell edge

throughput and so on.





Wireless network dimensioning intends to obtain the approximate EUTRAN scale. Based on

the network dimensioning, geography and traffic distribution, the network is pre-planned

in detail by using planning software and digital map.

Based on the network dimensioning and site information, the initially selected LTE site is

imported into the planning software, and coverage is estimated by parameters setting.

Then an analysis is made to check whether the coverage of the system meet the

requirements. If necessary, the height and tilt of the antenna and the eNodeB quantity are

adjusted to optimize the coverage. And then the system capacity is analyzed to check

whether it meets the requirement.

Plan implementation parameters, such as antenna type / azimuth / tilt / altitude / feeder

type / length …

Plan cell parameters, such as tracking area planning, PCI planning, Neighbor relation

planning, PRACH configuration planning…







The carrier bandwidth of LTE could be 6RBs, 12RBs, 25RBs, 50RBs, 100RBs , the number

of RB affects the cell border throughput directly

MIMO is normally the different configuration in LTE, it can improve the LTE coverage and

capacity, we should consider the gain of MIMO in planning

MCS : Modulation & Coding Scheme, which is a radio channel auto adaptive algorithm .

With high order MCS, the throughput can be higher, but it is not suitable in poor channel

condition. So we have to select different MSC for different channel quality when

calculating the coverage and capacity.

3GPP define a number of bands for LTE, so the propagation model should be selected

accordingly.



Generally, LTE has the same dimensioning procedure as the other wireless system

In the coverage dimensioning, the link is estimated according to elements such as plannedarea, network capacity, and equipment performance in order to obtain the allowed

maximum path loss. The maximum cell radius is obtained according to the radio

propagation model and allowed maximum path loss. And then the site coverage area is

calculated. Finally, the site quantity is calculated. Of course, the site quality is only for the

ideal cell status, and some additional sites will be needed in actual terrain environment.





The following propagation models can be used for LTE link budget.Cost231-Hata, SPM

and Cost231-Hata (Huawei) can be used for LTE band higher than 1500MHz. Okumura-

Hata and Okumura_Hata (Huawei)can be used for LTE band lower than 1500MHz.

Cost231-Hata

Cost231-Hata（Huawei）

Okumura- Hata

Okumura- Hata（Huawei）

SPM





Normally the link budget is limited by data channel, so in this course data channel link

budget is discussed mostly.





For Channel Mode:

EPA is Extended Pedestrian A model. EPA 3 means the speed in the model is 3km/h.

ETU is Extended Typical Urban. EUT 3, ETU 30, ETU 60 and ETU 120 means the

speed in the model is 3km/h, 30km/h, 60km/h and 120km/h.

EVA is Extended Vehicular A model. EVA 3, EVA 30, EVA 60 and EVA 120 means

the speed in the model is 3km/h, 30km/h, 60km/h and 120km/h.

HST is High Speed Train. HST 350 means the speed in the mode is 350km/h.

For MIMO Scheme:

SFBC is Space-Frequency Block Code.

FSTD is Frequency Switched Transmit Diversity.

MIMO can bring gain to LTE link budget. So MIMO scheme is considered in input

parameters.





Generally ,the max allowed path loss is calculated from the transmission power and the

reception sensitivity.

In the propagation, the Losses are normally static , such as penetration loss, body loss and

cable loss.

The gains (e.g. antenna gain, MIMO gain) can improve the max allowed path loss , since it

enhances the signal strength or it can bring some compensation to the losses.

The margins are reserved to ensure the coverage performance. With the margin revered ,

the coverage( calculated by link budget) can always satisfy the planning target even in case

of the cell is loaded or in somewhere the slow fading is greater than the average value.





EIRP is Equivalent Isotropic Radiated Power.

Considering indoor coveragePenetration Loss

is in the formula to calculateMAPL

. Shadow fading indicates the fading brought by obstruction due to a building or a natural

feature. Shadow fading changes slowly, and is thus called “slow fading”. Statistics

repeatedly show that the median levels of received signals follow log-normal distribution

with the time and location at a certain distance. Fading caused by location (mainly from

obstruction) far exceeds fading caused by time. Therefore, the major concern for shadow

fading is those caused by location changes.





In downlink the total power is distributed evenly over all subcarriers of the whole

bandwidth.





AWS band:

UL: 1710MHz – 1755MHz, DL:2110MHz – 2155MHz





Thermal noise per subcarrier is:

Thermal noise per subcarrier = 10*lg(K*T*W) = -132.2dBm K is Boltzman constant. It is equal to 1.38*10-23.

T is temperature in Kelvin. Normally it is 290.

W is the signal bandwidth. Here W is 15KHz (one subcarrier in LTE).





Target MCS, MIMO scheme, channel mode and etc. are input parameters for SINR

simulation.

Allocated RB number can be calculated by target cell edge rate and target MCS.





The interference margin in practice depends heavily on the planned capacity so there is a

tradeoff between capacity and coverage just like other cellular technologies.





Penetration Loss indicates the fading of radio signals from an indoor terminal to a base

station due to obstruction by a building. It is related to the incident angle, building

materials, terrain, and working frequency.





The shadow fading margin is related to the area coverage probability requirement and the

standard deviation of fading. The standard deviation of slow fading shows the distribution

of the radio signal strength at different test points at similar distances from the transmitter.

The standard deviation of slow fading varies with the geological form. In plain areas, such

as rural areas and open areas, the standard deviation of slow fading is lower than that in

suburban and urban areas. Standard deviations requirement in Dense Urban area with

highly integrated building layout and deeper indoor coverage requirement is even higher

than typical urban environment.





Higher the area coverage probability requirement is, more shadow fading margin is

required.

Higher the standard deviation is, more shadow fading margin is required.





The parameters with zero value are not shown in the table.





3GPP defines that maximum Tx power of LTE UE is 23dBm.





Thermal noise per subcarrier is:

Thermal noise per subcarrier = 10*lg(K*T*W) = -132.2dBm K is Boltzman constant. It is equal to 1.38*10-23.

T is temperature in Kelvin. Normally it is 290.

W is the signal bandwidth. Here W is 15KHz (one subcarrier in LTE).





AWS band:

UL: 1710MHz – 1755MHz, DL:2110MHz – 2155MHz





The parameters with zero value are not shown in the table.





By repeating the same uplink information, lower SINR will be required by the receivers at

the eNodeB. The application of this feature is ideal for lower data rate applications such as

VoIP and Packet data services requiring slower rate. At least 4 dB gain can be achieved

through this data repetition.

TTI bundling Gain is included as part of SINR in link budget estimation.





The concept of Interference Rejection Combining (IRC) is to regenerate the transmitted

signal based on the estimated data from the previous receptions, emulate the distortion

occurring from the multi-path channels and, finally subtract all regenerated interfering

signals from the uplink received signals to obtain more reliable estimation of original user’s

data. This feature utilizes the spatial separation and characteristics of inter-cell interference

to determine the power of the interfering UE which belongs to another cell. Once the

pattern and power level is determined, the victim cell can then remove the interferer from

the received signals.

In comparison, Maximum ratio combining (MRC) do not make use of the spatial

characteristics of the interference when calculating antenna weighting. So in cases where

there are only a small number of dominating interfering sources, IRC can provide more

improvement than MRC especially when there are a reasonable number of receive

antennae for IRC to execute the compensation. Conversely, if there are a large number of

equal power signals arriving at the receive antennae, the gain of IRC over MRC is not as

significant.

MRC is more applicable for the scenario with white noise while IRC is more applicable for

the scenario with colored noise.





RND is used for coverage dimensioning and capacity dimensioning.

GENEX U-NET is used for coverage prediction and capacity simulation during nominalplanning and detailed planning. GENEX-NET can also be used for LTE cell planning





Before dimensioning some common input parameters need to be set.





During dimensioning, RND can calculate or simulate some parameters based on input

parameters.





The figure is the result of best server prediction.





The figure is the result of downlink RSRP prediction.





The figure is the result of downlink RS SINR prediction.





The figure is the result of handover area prediction.





The figure is the result of PUSCH SINR prediction.



03.oep100310 lte radio network coverage dimensioning isuee 1.10.pdf

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