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Channel quality indicator (CQI)

FAST FACTS:

CQI is used in HSDPA as a measure of the downlink channel quality as perceived by the terminal which transmits the CQI values regularly to the nodeB which uses this information for scheduling of further downlink data transmissions.

·         Based on SIR-measurements on the Common Pilot Indicator Channel (CPICH) 

·         An increase of one step in the CQI value represents an increase of SIR of the CPICH by one db

·         Each 5 bit CQI value is directly mapped to a transport block size (TBS), number of channelization code and modulation degree. Depending on the capabilities of the receiver, these values may differ between receivers for each CQI value.

·         The nodeB uses these mapped values as an input to the scheduling algorithm.

·         The scheduling algorithm for most implementations also considers other parameters such as buffer status and priority levels.

·         The CQI values range between 0(worst) and 30(highest).

·         CQI values and their respective mappings to TBS, number of channelization codes and modulation degree for each HSDPA category can be found in 3GPP specs

Some links to follow

Blogroll:

technologyhttp://3g4g.blogspot.com/ ---------probably the best
http://lte-epc.blogspot.com/ ---------purely study material on LTE
http://mobilesociety.typepad.com/mobile_life/ --------lots of personal reflections, but some really good tech reviews
http://wirelesstechbites.blogspot.com/ -------has'nt been updated since Dec 2009, still lots of good stuff here
http://wired-n-wireless.blogspot.com/ -------more stuff on LTE
http://ltewatch.blogspot.com/ --------- LTE business news
http://www.ericsson.com/thecompany/our_publications ---------technical articles, the best 

Business news
http://www.dailywireless.org
http://www.xperiablog.net/
http://www.intomobile.com/
http://www.mobile-review.com/index-en.shtml
http://www.fiercewireless.com/
http://www.itbusinessedge.com/cm/blogs/weinschenk
http://disruptivewireless.blogspot.com/
http://www.wirelessweek.com/http://
ltewatch.blogspot.com/

Telecom organisations
http://www.umtsforum.org/
http://www.etsi.org/WebSite/homepage.aspx
http://www.itu.int/net/about/index.aspx
http://www.3gamericas.org/
http://www.3gpp.com/
http://www.gsacom.com/index.php4 ------------ NW vendors own stat's on existing NW capabilities
http://www.gsmworld.com/ ----------------- operators organisation


Telecom companys,
http://www.qualcomm.com/stories
http://www.nokiasiemensnetworks.com/news-events/publications
http://www.alcatel-lucent.com/publications/
http://www.stericsson.com/press/press_archive.jsp
http://www.sierrawireless.com/en/productsandservices/AirPrime/Wireless_Modules/High-speed.aspx http://www.huaweidevice.com/worldwide/productDirectory.domethod=index&directoryId=2041&treeId=41
http://www.option.com/en/products/products/embedded-mobile-broadband/

why nokia is using st ericssons novathor arm chip instead of qualcomm

Great stuff for understanding more about different smartphone platforms :)

why-nokia-is-using-st-ericssons-novathor-arm-chip-instead-of-qualcom

Heterogeneous networks (hetnets)

The following is a summary of an article in ericsson review  December 28, 2011

In locations where the number of users are high a densified infrastructure can provide the increase in NW capacity that is needed. This can be achieved with a layered cell structure meaning that multiple and equally available cells have overlapping coverage areas.  Typically, the traditional macro cell transmitting with high power over a large coverage area is complemented with pico cells transmitting with low power over a smaller coverage area that is geographically covering a part of the coverage area of the macro cell. In addition to simply selecting the cell with the strongest signal, the cell selection algorithm should in this case  also incorporate cell congestion and backhaul capacity. Heterogeneous network deployment can be achieved with two different approaches, resource partitioning and soft-cell  schemes:

·         Resource partitioning can be achieved in either the frequency or the time domain which in reality creates separate cells with individual system information and synchronization signals transmissions.

·         In shared cell or soft cell schemes, the low power pico cells are part of the macro cell but with a Cell Specific Reference signal (CRS) which determines which part of the System Information that is relevant. Also, a Demodulation specific Reference Signal (DM-RS) is used to determine which transmission point (macro or pico cell) the terminal should use.

Heteroge­neous deployments that use soft cells can provide greater mobility robust­ness than deployments with separate cells. This is important, especially when moving from a low-power node to the macro. In separate cell deployment, a handover procedure is required to switch serving cells. If, during the time it takes to perform the handover procedure, the terminal has moved too far into the macro area, it may drop the downlink connection from the low-power node before handover is complete – leading to a radio-link failure. In soft-cell deployment, the transmission point that should be used for downlink trans­mission can be changed rapidly without a handover procedure – thus reducing the probability of dropped connections.

the article in its entirety can be found at
heterogeneous_network_deployments_lte