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Monday, December 28, 2015

How to enable Samsung Galaxy S5/S4 for QXDM

Enable Developers option for USB debugging:
Go to Settings ->More->About Device and tap on the build number 3-5 times. It will notify that developer option is enabled.
Go back to Developers options and settings and Select USB debugging

Enables Modem Option on the Samsung Galaxy S5/S4:
Go to  Samsung Galaxy S5/S4 dialer and dial *#0808#. The USB Settings will opened.
Go to AP USB settings select the "RNDIS + DM + MODEM" and Click OK.

Connect the Samsung Galaxy S4/S5 to laptop and check the device manager. There must be a com port appear for your laptop. make note of the comm port and use it QPST and QXDM.


Thursday, May 28, 2015

SRVCC - Subscribers VoLTE call will drop if out of VoLTE coverage?

SRVCC - Single Radio Voice Call Continuity

    Does the VoLTE call drop when out of VoLTE enabled cell coverage? Answer is Yes and a No. Potential solution is supporting SRVCC for call continuity with inter-RAT systems. SRVCC is adapted as standard but not something developed for VoLTE. SRVCC was designed to facilitate IMS Achored voice call continuity between LTE/HSPA network and GSM/UMTS/CDMA Networks.  This not as simple solution, since the voice call continuity is between Packet switch network and Circuit switched networks.
    Attach procedure is used to exchange the information about letting each other know SRVCC capability of UE and MME.  MSC-S, MME and UE needs to support SRVCC for the voice call continuity. Series of handover procedures carried out to move the voice leg from one RAT to another.

Wednesday, May 27, 2015

VoLTE - Voice over LTE - Must Know!

How will UE know that VoLTE is supported by the EPC network?

    During the NAS Attach procedure or NAS TAU procedure, in the Attach Accept and/or RAU Accept message, additional IE called "EPS Network Feature" will be included indicating "IMS Over PS session" is available. This triggers the UE to register with IMS network.

VoLTE Call Procedures - Call flow:

  In VoLTE call establishment procedure is achieved using a application server called Telephony Application Server(TAS).
Procedure includes:
  • Establishment of Default EPS Bearer with  QCI = 5
  • SIP Call Establishment Procedures
  • Establishment of Dedicated EPS Bearer to support Media Bearer
  • SIP Call Termination Procedures
  • Termination of Dedicated EPS Bearer

Thursday, December 4, 2014

LTE - Feature set in each 3GPP release

LTE is a flat IP architecture, bringing in higher data rates with improvements of radio access technologies. In addition to that it is way say good bye to circuit switched network by moving completely to packed switched network. This intern reduces both CAPEX and OPEX.

LTE is introduced in 3GPP release 8.

Release 8:

  • All IP network
  • New air interface
  • Reduced latency
  • Support for MIMO antennas
  • Higher data rates: 300Mbps/75Mbps

Release 9:

  • Introduction of small cells
  • Self Organizing Networks (SON)
  • evolved Multimedia Broadcast and Multicast service (eMBMS)
  • Location Services

Release 10:

  • 3Gbps/1.5Gbps data rates
  • 8x8 downlink and 4x4 uplink MIMO antennas
  • Carrier aggregation of 20 MHz channels to maximum 100 MHz channel
  • Relay nodes to support Heterogeneous Networks (HetNet)

Release 11:

  • Improvements to carrier aggregation
  • New frequency bands
  • Improvements to receivers
  • Multipoint transmission and reception

Monday, February 24, 2014

Inter-frequency Hard Handover Events in Small Cells


During the hard handover procedure for inter-frequency, when the UE is moving away from HNB coverage area, HNB will receive the event 2D when quality of the currently used frequency is below the 2D threshold configured. When the event 2D is triggered, compressed mode scanning will be started.  If the UE moves further away and satisfy the event 2B condition when estimated quality of the currently used frequency is below the 2B threshold configured and estimated quality of the non-used frequency is above the configured threshold. Event 2B will trigger the handover procedure.
However if the Event 2D threshold is met and compressed mode measurement reporting is started but UE is moving towards the HNB coverage area and the estimated quality of the currently used frequency is better than the configured 2F threshold, UE will exit the compressed mode.

Thursday, January 16, 2014

3G/UMTS Inter-frequency, Intra-frquency and Inter-RAT handover events

Intra-frequency Handover Events:

Event 1a: A Primary CPICH enters the Reporting Range (FDD only).
Event 1b: A Primary CPICH leaves the Reporting Range (FDD only).
Event 1c: A Non-active Primary CPICH becomes better than an active Primary CPICH (FDD only).
Event 1d: Change of best cell (FDD only).
Event 1e: A Primary CPICH becomes better than an absolute threshold (FDD only).
Event 1f: A Primary CPICH becomes worse than an absolute threshold (FDD only).
Event 1g: Change of best cell in TDD.
Event 1h: Timeslot ISCP below a certain threshold (TDD only).
Event 1i: Timeslot ISCP above a certain threshold (TDD only).
Event 1j: A Non-active E-DCH but active DCH Primary CPICH becomes better than an active E-DCH Primary CPICH (FDD only).

When an Event 1C is received, Handover procedure will be started in the NodeB.

Inter-frequency Handover Events:

Event 2a:
Change of best frequency.
Event 2b: The estimated quality of the currently used frequency is below a certain threshold and the estimated quality of a non-used frequency is above a certain threshold.
Event 2c: The estimated quality of a non-used frequency is above a certain threshold.
Event 2d: The estimated quality of the currently used frequency is below a certain threshold.
Event 2e: The estimated quality of a non-used frequency is below a certain threshold.
Event 2f: The estimated quality of the currently used frequency is above a certain threshold.

Event 2B will trigger the inter-frequency handover procedure in the Node B. Event 2D will start the compressed mode scanning and Event 2F will stop the compressed mode.

Inter-RAT Handover Events:

Event 3a: The estimated quality of the currently used UTRAN frequency is below a certain threshold and the estimated quality of the other system is above a certain threshold.
Event 3b: The estimated quality of other system is below a certain threshold.
Event 3c: The estimated quality of other system is above a certain threshold.
Event 3d: Change of best cell in other system.

Event 3A will trigger the inter-frequency handover procedure in the Node B
 

UMTS: Traffic Volume Measurement (HSDPA, HSUPA)

Traffic Volume Measurement is used for purpose of Rate reallocation at UE. The monitored traffic volume corresponds to the amount of data in number of bytes that is available for transmission and re-transmission in RLC layer- Buffer Occupancy.
When an UE supporting Release 5 and below release is used then rate adaptation can be achieved. As the buffer occupancy goes lower than the threshold, Timer will be started. If the buffer occupancy goes above the threshold then it will stopped. If the timer expires then data rate will be adapted to lower rate for the UE.
Event 4a: Transport Channel Traffic Volume exceeds an absolute threshold.
Event 4b: Transport Channel Traffic Volume becomes smaller than an absolute threshold.

Traffic volume measurements may be configured by RRC to assist with dynamic radio bearer control. In general, RLC buffer payload, Average of RLC buffer payload or Variance of RLC buffer payload will be configured to report.

Traffic volume measurement reports can be triggered periodically and event triggered based on the reporting criteria specified in the measurement control message.

Traffic volume measurement information will be communicated in SIB11 and during the radio bearer setup stage.