SAMSUNG GALAXY S3

HANDOVER EXPLAINED

• A hard handover is one in which the channel in the source cell is released and only then the channel in the target cell is engaged. Thus the connection to the source is broken before or 'as' the connection to the target is made—for this reason such handovers are also known as break-before-make. Hard handovers are intended to be instantaneous in order to minimize the disruption to the call. A hard handover is perceived by network engineers as an event during the call. It requires the least processing by the network providing service. When the mobile is between base stations, then the mobile can switch with any of the base stations, so the base stations bounce the link with the mobile back and forth. This is called ping-ponging.

• A soft handover is one in which the channel in the source cell is retained and used for a while in parallel with the channel in the target cell. In this case the connection to the target is established before the connection to the source is broken, hence this handover is called make-before-break. The interval, during which the two connections are used in parallel, may be brief or substantial. For this reason the soft handover is perceived by network engineers as a state of the call, rather than a brief event. Soft handovers may involve using connections to more than two cells: connections to three, four or more cells can be maintained by one phone at the same time. When a call is in a state of soft handover, the signal of the best of all used channels can be used for the call at a given moment or all the signals can be combined to produce a clearer copy of the signal. The latter is more advantageous, and when such combining is performed both in the downlink (forward link) and the uplink (reverse link) the handover is termed as softer. Softer handovers are possible when the cells involved in the handovers have a single cell site.

An advantage of the hard handover is that at any moment in time one call uses only one channel. The hard handover event is indeed very short and usually is not perceptible by the user. In the old analog systems it could be heard as a click or a very short beep, in digital systems it is unnoticeable. Another advantage of the hard handoff is that the phone's hardware does not need to be capable of receiving two or more channels in parallel, which makes it cheaper and simpler. A disadvantage is that if a handover fails the call may be temporarily disrupted or even terminated abnormally. Technologies, which use hard handovers, usually have procedures which can re-establish the connection to the source cell if the connection to the target cell cannot be made. However re-establishing this connection may not always be possible (in which case the call will be terminated) and even when possible the procedure may cause a temporary interruption to the call.

One advantage of the soft handovers is that the connection to the source cell is broken only when a reliable connection to the target cell has been established and therefore the chances that the call will be terminated abnormally due to failed handovers are lower. However, by far a bigger advantage comes from the mere fact that simultaneously channels in multiple cells are maintained and the call could only fail if all of the channels are interfered or fade at the same time. Fading and interference in different channels are unrelated and therefore the probability of them taking place at the same moment in all channels is very low. Thus the reliability of the connection becomes higher when the call is in a soft handover. Because in a cellular network the majority of the handovers occur in places of poor coverage, where calls would frequently become unreliable when their channel is interfered or fading, soft handovers bring a significant improvement to the reliability of the calls in these places by making the interference or the fading in a single channel not critical. This advantage comes at the cost of more complex hardware in the phone, which must be capable of processing several channels in parallel. Another price to pay for soft handovers is use of several channels in the network to support just a single call. This reduces the number of remaining free channels and thus reduces the capacity of the network. By adjusting the duration of soft handovers and the size of the areas, in which they occur, the network engineers can balance the benefit of extra call reliability against the price of reduced capacity.

GBR IN LTE

GBR

Guaranteed Bit Rate. A minimum bit rate requested by an application. In LTE, minimum GBR bearers and non-GBR bearers may be provided. Minimum GBR bearers are typically used for applications like Voice over Internet Pro- tocol (VoIP), with an associated GBR value; higher bit rates can be allowed if resources are available. Non-GBR bearers do not guarantee any particular bit rate, and are typically used for applications as web-browsing.

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AMSUNG GALAXY S PLUS SPECIFICAYIONS

ENERAL	2G Network	GSM 850 / 900 / 1800 / 1900
	3G Network	HSDPA 900 / 1900 / 2100
	Announced	2011, April
	Status	Available. Released 2011, July

BODY	Dimensions	122.4 x 64.2 x 9.9 mm
	Weight	119 g
		- Touch-sensitive controls

DISPLAY	Type	Super AMOLED capacitive touchscreen, 16M colors
	Size	480 x 800 pixels, 4.0 inches (~233 ppi pixel density)
	Multitouch	Yes
	Protection	Corning Gorilla Glass
		- TouchWiz 3.0 UI

SOUND	Alert types	Vibration; MP3, WAV ringtones
	Loudspeaker	Yes
	3.5mm jack	Yes

MEMORY	Card slot	microSD, up to 32GB
	Internal	8/16 GB storage (market dependent), 512 MB RAM, 512 MB ROM

DATA	GPRS	Class 12 (4+1/3+2/2+3/1+4 slots), 32 - 48 kbps
	EDGE	Class 12
	Speed	HSDPA, 14.4 Mbps; HSUPA, 5.76 Mbps
	WLAN	Wi-Fi 802.11 b/g/n, DLNA, Wi-Fi hotspot
	Bluetooth	Yes, v3.0 with A2DP
	USB	Yes, microUSB v2.0

CAMERA	Primary	5 MP, 2592 x 1944 pixels, autofocus,
	Features	Geo-tagging, touch focus, face and smile detection
	Video	Yes, 720p@30fps
	Secondary	Yes, VGA

FEATURES	OS	Android OS, v2.3 (Gingerbread)
	Chipset	Qualcomm MSM8255T Snapdragon
	CPU	1.4 GHz Scorpion
	GPU	Adreno 205
	Sensors	Accelerometer, proximity, compass
	Messaging	SMS(threaded view), MMS, Email, Push Mail, IM, RSS
	Browser	HTML, Adobe Flash
	Radio	Stereo FM radio with RDS
	GPS	Yes, with A-GPS support
	Java	Yes, via Java MIDP emulator
	Colors	Black, White
		- Social networking integration - MP4/DivX/Xvid/WMV/H.264/H.263 player - MP3/WAV/eAAC+/AC3/FLAC player - TV-out - Organizer - Image/video editor - Document editor (Word, Excel, PowerPoint, PDF) - Google Search, Maps, Gmail, YouTube, Calendar, Google Talk, Picasa integration - Voice memo/dial/commands - Predictive text input (Swype)

BATTERY		Standard battery, Li-Ion 1650 mAh
	Stand-by	Up to 480 h (2G) / Up to 430 h (3G)
	Talk time	Up to 17 h 20 min (2G) / Up to 7 h 50 min (3G)

MISC	SAR US	0.44 W/kg (head)     0.94 W/kg (body)
	SAR EU	0.35 W/kg (head)
	Price group