- This topic has 9 replies, 1 voice, and was last updated 10 years, 8 months ago by Pedro Miguel Saraiva Santos.
21st August 2007 at 14:38 #48949emreGuest
what it mean hard handower, soft handover and softer handover22nd August 2007 at 04:26 #48950asoGuest
the meaning of Hard handover is mean that when the mobile send handover coammand and get handover complete it will move from the source cell to target cell but ( no more relation to sourse cell) which this kind of handovr is exist in 2g and for the soft handover is the same prcedure as before but it will be in cantact with source cell which it exist is 3g it look like chain with out break but is 2g the chain is breaking22nd August 2007 at 05:14 #48951IrfanGuest
Hi aso kindly confrim me that is in 2g handover type is Hard handover and 3g is soft handover and why we need contact with source cell in 3g?22nd August 2007 at 07:25 #48952deaf and dumbGuest
in CDMA, the frequency on which the mobile communicates doesnot change but the orthogonal codes change….the mobile changes the code but not frequency so it is called a soft handover (unlike gsm in which frequency also changes,). in CDMA, the mobile keeps on measuring on the same frequency but different code.22nd August 2007 at 08:36 #48953pixGuest
soft handover : during the call, the mobile is connected to two cells at the same time, or sometimes more than 2 ! The soft HO happens when the mobile actually stops communicating with one of the cells in the “active set” (low level maybe, or bad quality, etc..)
hard handover : it is the type of handovers used in 2G GSM, no doubt about that 🙂
oh, i just found this :
There are following categories of handover (also referred to as handoff):
# Hard Handover
Hard handover means that all the old radio links in the UE are removed before the new radio links are established. Hard handover can be seamless or non-seamless. Seamless hard handover means that the handover is not perceptible to the user. In practice a handover that requires a change of the carrier frequency (inter-frequency handover) is always performed as hard handover.
# Soft Handover
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. Normally soft handover can be used when cells operated on the same frequency are changed.
# Softer handover
Softer handover is a special case of soft handover where the radio links that are added and removed belong to the same Node B (i.e. the site of co-located base stations from which several sector-cells are served. In softer handover, macro diversity with maximum ratio combining can be performed in the Node B, whereas generally in soft handover on the downlink, macro diversity with selection combining is applied.
(cf [url]www.umtsworld.com/technology/handover.htm[/url])22nd August 2007 at 10:19 #48954asoGuest
as you know in 3G tackling with CDMA multiple access which depend on code not frequency or time as in 2G therefore this kind for technique is more sensitive and therefore it connect to two or more sites in the same time because may be send the same code which make it more reliable for Mobile to have precise signal strength23rd August 2007 at 06:28 #48955IrfanGuest
Thanks a lot for guiding me31st August 2007 at 15:39 #48956sasaGuest
thanks a lot1st September 2007 at 12:26 #48957paraHOGuest
deaf and dumb, you said
“…the mobile changes the code but not frequency…”
Are you saying the code is the same for all Masts that the mobile is connected?
Are you saying a different code exists for each of the Masts the mobile is connected so that the mobile knowns to which Mast to handover?10th July 2010 at 19:02 #48958Pedro Miguel Saraiva SantosGuest
UMTS issue : We´ve seen lots of Dropped calls like this one : lot´s of “Measurement Reports” to delete one of the Radio links (1b), but with no “Active Set Update Update” message.The Best Scrambling Code CEll is with Good EcNo.Finally the Call Dropped.Why the system doesn´t delete the Bad Radio link cell, and that way save the call? Just Before the Call Dropped, sudden Increase of SIR.Any Explanation for this ?Thanks a lot, Pedro Saraiva