HSDPA Frame Loss

These counters relating to frame loss are available on the RBS to monitor HighSpeed data service in the downlink direction.

IubDataStreams::pmHsDataFramesLostSpiXX
- the number of HSdata frames lost, destroyed and errored over Iub in the RBS. There areseparate counters for each of the priority classes.

IubDataStreams::pmHsDataFramesReceivedSpiXX
- the totalnumber of HS data frames correctly received over Iub in the RBS. Thereare separate counters for each of the priority classes.

The XX suffix represents the priority class and can range from 00 to 15.The counters can be used to indicate data loss rate for the HS service.High frame loss will indicate potential congestion problems. RecommendedPerformance Indicator for this is:



Frame Loss Rate on the path from SRNC to RBS

Find more HSDPA Counters at www.telecomfunda.com/forum

VoLTE + Wi-Fi = LTE Femto

This week, Kineto announced it now supports the GSMA’s VoLTE profile (IMS voice & SMS) in its Smart Wi-Fi client. Smartphones with the Smart Wi-Fi client will now be able to receive the mobile operator’s voice/SMS service (VoLTE) when attached to Wi-Fi.
I have always believed LTE and Wi-Fi were two sides of the same coin – both are high-speed, low-latency flat IP networks. LTE covers the macro/outdoor world, and Wi-Fi is by far the dominant in-building wireless technology. Marrying the two technologies into a seamless experience delivers a compelling experience for mobile subscribers.
In the move to LTE, mobile operators are adopting VoLTE, an IMS/SIP-based voice and SMS profile that replaces (replicates?) the existing circuit voice/SMS services used in GSM/UMTS networks.

UE Measurements

Intra-frequency measurements: measurements on downlink physical channels at the same frequency as the active set. A measurement object corresponds to one cell.

Inter-frequency measurements: measurements on downlink physical channels at frequencies that differ from the frequency of the active set. A measurement object corresponds to one cell.

Inter-RAT measurements: measurements on downlink physical channels belonging to another radio access technology than UTRAN, e.g. GSM. A measurement object corresponds to one cell.

Traffic volume measurements: measurements on uplink traffic volume. A measurement object corresponds to one cell.

Quality measurements: Measurements of downlink quality parameters, e.g. downlink transport block error rate. A measurement object corresponds to one transport channel in case of BLER. A measurement object corresponds to one timeslot in case of SIR (TDD only).

UE-internal measurements: Measurements of UE transmission power and UE received signal level.

UE positioning measurements: Measurements of UE position.The UE supports a number of measurements running in parallel. The UE also supports that each measurement is controlled and reported independently of every other measurement.

Cyclic Delay Diversity

Cyclic Delay Diversity (CDD) is a simple approach to introduce spatial diversity to an Orthogonal Frequency Division Multiplexing (OFDM) based transmission scheme that itself has no built-in diversity. It also can be regarded as a Space-Time Code (STC).

But in contrast to that there is no additional effort in the receiver necessary, since the different codewords result in a changed channel impulse response in the receiver. They insert virtual echos and thus increase the frequency selectivity of the channel seen by the receiver. Cyclic Delay Diversity (CDD) is a diversity scheme used in OFDM-based telecommunication systems, transforming spatial diversity into frequency diversity avoiding intersymbol interference.

RSRP and RSRQ

In cellular networks, when a mobile moves from cell to cell and performs cell selection/reselection and handover, it has to measure the signal strength/quality of the neighbor cells. In LTE network, a UE measures two parameters on reference signal: RSRP (Reference Signal Received Power) and RSRQ (Reference Signal Received Quality).

RSRP is a RSSI type of measurement. It measures the average received power over the resource elements that carry cell-specific reference signals within certain frequency bandwidth. RSRP is applicable in both RRC_idle and RRC_connected modes, while RSRQ is only applicable in RRC_connected mode. In the procedure of cell selection and cell reselection in idle mode, RSRP is used.

RSRQ is a C/I type of measurement and it indicates the quality of the received reference signal. It is defined as (N*RSRP)/(E-UTRA Carrier RSSI), where N makes sure the nominator and denominator are measured over the same frequency bandwidth.

The carrier RSSI (Receive Strength Signal Indicator) measures the average total received power observed only in OFDM symbols containing reference symbols for antenna port 0 (i.e., OFDM symbol 0 & 4 in a slot) in the measurement bandwidth over N resource blocks. The total received power of the carrier RSSI includes the power from co-channel serving & non-serving cells, adjacent channel interference, thermal noise, etc.

The RSRQ measurement provides additional information when RSRP is not sufficient to make a reliable handover or cell reselection decision. In the procedure of handover, the LTE specification provides the flexibility of using RSRP, RSRQ, or both.

Benefits of CPICH Optimization

Benefits of CPICH Optimization

• Improving current 3G coverage and increase 3G traffic
• Improve in-building penetration for 3G
• Reduce IRAT HO to 2G
• Offload traffic from 2G layer

What is Pilot Polution?

In idle or cell_FACH mode, phenomenon of the pilot pollution is that a UE cannot firmly camp on a cell at one location because of receiving many pilot channels with similar quality (or signal strength), i.e., Ec/No (or RSCP).
The condition to determine the area has pilot pollution in idle or cell_FACH mode is that third pilot appears in the cell re-selection region.
In cell_DCH mode, phenomenon of the pilot pollution is that a UE at one location frequently changes its active set cells (active set update rate is very high) because of receiving many pilot channels with similar quality (or signal strength), i.e., Ec/No (or RSCP). It causes high signaling load in RRC and Iub interfaces and the capacity of RNC is consequently reduced.

May be useful to you
WCDMA Tilt and CPICH Power Adjustment

Solution for Pilot Polution in the network:

Reason – no dominant cell
The reason is too many overlapping cells at an area due to poor cell planning.
Solution 1
The direct solution is to remove the cells overlapping by changing the antenna configurations or reducing pilot powers of the unwanted cells.
Solution 2
The most effective solution is to increase the pilot channel power Primary CPICH power of the desired cell.
Solution 3
For the pilot pollution in idle or cell_FACH mode, Q Offset 2sn (CPICH Ec/No) parameter of the desired cell can be increased to create a dominated cell.