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RSRP, RSSI and RSRQIn LTE network, UEs need to measure signal strength of its own and neighbor cells constantly,

during idle, connected mode or handovers in order to keep the signal quality constant. UE measures

!" and !# in LTE

Reference Symbol Received Power (RSRP): !" is the linear average of the downlink reference signals across the channel bandwidth

!" provides information about signal strength and gives no indication of signal quality

!" measurements are used in handover, cell selection and cell re$selections

The reporting range of !" is defined from $%&' d(m to $&& d(m with % d( resolution as

shown in table below

RSRP measurement report mapping (3GPP Reference: TS 36.133)

Received Signal Strength Indicator (RSSI): !!I represents the total received wide$band power by UE

!!I is measured only in symbols containing eference signals

!!I includes power from serving cell as well as co$channel interference and noise

!!I helps in determining interference and noise information

!!I is never reported by UE

Reference Signal Received Quality (RSRQ): !# indicates quality of received reference signal. !# measurement and calculation is

based on !" and !!I since !" determines signal quality and !!I determines co$channel

interference and noise. !# formula is shown below )* represents number of resource blocks+

The reporting range of !# is defined from $%.- d( to $ with '.- d( resolution

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RSRQ measurement report mapping (3GPP Reference: TS 36.133)

Examle

Lets try to calculate !", !!I and !# for one very simple

case of one resource block with %/ sub carriers and '.- ms in time domain. 0or sake of simplicity,

lets assume the power of reference symbols )shown by red square+ and power of other symbols

carrying other data channels )shown by blue square+ is same i.e. '.'/% watt

!ince !" is linear average of downlink reference signal for given channel bandwidth therefore

RSRP ! "#$log (#%#&"$"###) ! "'%& dm

1hile !!I is total received wide$band power. Therefore we have to add power of all %/ carriers in

the given resource block

RSSI ! "#$log(#%#&"$"###)"#$log("&) ! &* dm

!# is now simple ratio of !" to !!I with *2%

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RSRQ ! "#$log(#%#&"+("&$#%#&")) ! "#%-. d

/hy do we u0e dm a0 a unit of Power1e use decibels$milliwatts to measures power levels in telecommunication and other fields instead

of 1att. The reason to use logarithmic scale is that it helps in reducing massive values to smaller

number

Examle :'.''''''''''''3' watt which apparently looks very small value but

can still be received by antenna. The logarithmic value is 4ust $% dbm by using below formula

" )d(m+ 2 %' 5 Log )%'''6"+