TelecomStudy18

What is SIR? SIR is the Signal-to-Interference Ratio – the ratio of the energy in dedicated physical control channel bits to the power density of interference and noise after dispreading. What is RSCP? RSCP stands for Received Signal Code Power – the energy per chip in CPICH averaged over 512 chips. What is Eb/No? By definition Eb/No is energy bit over noise density, i.e. is the ratio of the energy per information bit to the power spectral density (of interference and noise) after dispreading. Eb/No = Processing Gain + SIR For example, if Eb/No is 5dB and processing gain is 25dB then the SIR should be -20dB or better. What are the Eb/No targets in your design? The Eb/No targets are dependent on the service:  on the uplink, typically CS is 5 to 6dB and PS is 3 to 4dB – PS is about 2dB lower.  on the downlink, typically CS has 6 to 7dB and PS is 5 to 6dB – PS is about 1dB lower. Why is Eb/No requirement lower for PS than for CS? PS has a bet...

Handover Parameter maxActiveSet: Maximum number of cells allowed in the Active Set. IndividualOffset: Offset value which can be assigned to each cell. It is added to the measurement quantity before the UE evaluates whether or not an event has occurred. It can either be positive or negative value. measQuantity1: Defines the measurement quantity for intra-frequency reporting evaluation. Default is Ec/No . hsQualityEstimate: Indicates whether Ec/No or RSCP should be used for indicating "best cell" for HS-DSCH Cell Change. Default is RSCP. reportingRange1a: Relative threshold referred to the CPICH of the best cell in the Active Set used as evaluation criteria for event 1a (a primary CPICH enters the reporting range). reportingRange1b: Relative threshold referred to CPICH of the best cell in the Active Set used as evaluation criteria for event 1b (a primary CPICH leaves the reporting range). reportingInterval1a: Time between periodic reports at even...

 e1a – a Primary CPICH enters the reporting range, i.e. add a cell to active set.  e1b – a primary CPICH leaves the reporting range, i.e. removed a cell from active set.  e1c – a non-active primary CPICH becomes better than an active primary CPICH, i.e. replace a cell.  e1d : change of best cell.  e1e : a Primary CPICH becomes better than an absolute threshold.  e1f : a Primary CPICH becomes worse than an absolute threshold.

Advantages:   Overcome fading through macro diversity.   Reduced Node B power which in turn decreases interference and increases capacity.   Reduced UE power (up 4dB), decreasing interference and increasing battery life. Disadvantages:   UE using several radio links requires more channelization codes, and more resources on the Iub and Iur interfaces

GSM:  Time -based mobile measures of RxLev and RxQual – mobile sends measurement report every SACH period (480ms).  BSC instructs mobile to handover based on these reports. UMTS:  Event -triggered reporting – UE sends a measurement report only on certain event “triggers”.  UE plays more part in the handover decision.

Handover: call transfer one cell to another cell without disconnecting There are three types of handover used in WCDMA. 1.    Intra frequency Handover (Soft & Softer ) 2.    Inter frequency handover 3.    IRAT Handover Soft Handover:             WhenHandover between two NodeB within same carrier frequency and add in active set. Soft handover means that the radio links are added and removed in a way that the UE always keeps at least one radio link to the UTRAN. Soft handover is performed by means of macro diversity, which refers to the condition that several radio links are active at the same time. Softer Handover:                         When Handover between two cells within same NodeB and ADD in active set. IRAT Handover:    ...

Power Control: We know all users are in same frequency at same time soPower control is used to controlled the level of the transmitting power in order to minimize interference,improve quality of connection, reducing of NEAR-FAR effects and increase capacity of system. There are three type of power control Open loop power control Inner loop Closed loop power control Outer loop closed loop power control Open loop power control:                                       The UE determine an estimation of the downlink path-loss between thee base station and the UE by the measuring of UTRA carrier received signal strength at the mobile through the medium of the SI message on the P-CCPCH.   Outer loop closed loop power control:            ...