Friday, February 11, 2011

What is AGPS (Assisted GPS)

Assisted GPS is used to assist the GPS by providing the additional information like visible GPS satellites, reference time, Doppler which would help in GPS acquisition process. This feature intern help faster GPS acquiring time and reducing the GPS power consumption. Also helps in more accurate GPS measurements with more coverage.

Friday, February 4, 2011

How to set automatic recovery after power failure for a SUN Netra box using ALOM port command

Pick up a laptop and cable which has RJ-47 in one end and 7-Pin serial port on the other end.

Connect RJ-47 to SERIAL MGT port in the Sun Box and serial port to your laptop. Make sure that you have a application like putty for the serial connection. Serial connection configuration shall be 9600/8n1/none. Establish a serial connection using putty, either console login prompt will appear or ALOM port login prompt appears. Please provide login and password, takes you to ALOM prompt or console window. If you wish to go to ALOM prompt from console then type “#.”(HASH and DOT). If you wish to switch to console prompt from ALOM then type “console”.

How to set automatic recovery after power failure for a SUN Netra box using ALOM port command

Please refer the How to connect to ALOM port section in this website. Once you login to SUN box and able to see the ALOM prompt sc>, you can use setsc command.
sc> showsc
Check the value for sc_powerstatememory variable. It shall show as below:
sc_powerstatememory false
To set the automatic recovery after power failure, do as below
sc> setsc sc_powerstatememory true
For any other commands use showsc and below syntax
sc> setsc <variable> <Value>


AMR: Discontinuous TX (DTX)

Mobile Battery life will be prolonged or a smaller battery could be used for a given operational duration. From the network point of view, the average required bit rate is reduced, leading to a lower interference level and, hence, increased capacity.




How to acheive DTX in AMR?

- Voice Activity Detector on TX side

- Evaluation of the background acoustic noise on the TX side

- Transmission of comfort noise information to the RX side using SID at regular intervals

- Generation of comfort noise on the RX side during periods when no normal speech frames are received.

What is Unlicensed Mobile Access - UMA

UMA provides tunneled IP connection to GSM/GPRS services through WiFi frequencies. But it needs dual mode mobile, to support roaming between wireless networks and unlicensed WiFi networks. UMA Network controller (UNC) is critical network node interworking between tunneled WiFi connection and cellular network.





Picture is referenced from book by Harri Holma and Antti Toskala

Thursday, February 3, 2011

What is Push-to-Talk over Cellular (PoC)

PoC is a one way communication over cellular network or called half duplex communication where voice call is full duplex. PoC called as walkie-talkie over PS domain of cellular networks. Best advantage is airtime which would be 1/4th or even less because voice packets transferred only one direction at a time. Radio resources can be allocated and released when needed.

Saturday, December 25, 2010

LTE as an all IP architecture

LTE (Long term evolution) is the latest standard for mobile network technology, specifications are available in the 3GPP standard. LTE is also an all IP architecture supported by major vendors like AT&T, T-Mobile, Verizon and more. Best part of the technology is that it also provides the inter-working for non 3GPP systems like 3GPP2 (CDMA)and WiFi, WiMax etc. Non 3GPP system are divided into trusted and non-trusted, based on that architecture will change. It is also called as 4G technology in mobile network industry. 3GPP release 8 and above specification talks about adapting to LTE. LTE started as a technology which support packet data network, later to support voice over the packet data network.
What is more fascinate about LTE?
- All IP Architecture
- Signaling and Data path separated out using MME and S-GW where PS Core and CS core is merged into single core network
- High data rates
- Decreased latency
- Better spectrum efficiency
- Scalable bandwidth
- Support for paired and unpaired spectrum
- Inter-working with 3GPP and non 3GPP systems

Below is reference architecture and inter-working with existing 3GPP systems (Reference 3GPP specifications: 3gpp.org)



Concerns operators shall have could be
- Cost effective evolution of IMS and LTE
- Spectrum efficiency
- Service quality
- Coverage performance
- CAPEX and OPEX

Target would be to address these concerns. However lot depends on the approaches that would be considered by operators for the architecture. Most of them probably consider overlay architecture and gradual transition.

If you have any questions please try to post the same. I would try to answer the same.