BTS power control in GSM

BTS power control
Parameter	Description	Range	Ericsson Dafault Value	Remarks
DBPSTATE	Dynamic BTS power control state	ACTIVE, INACTIVE	INACTIVE
SDCCHREG	SDCCH power control switch	ON, OFF	OFF	SDCCH power control switch. Identifies if power control on SDCCH is allowed on non BCCH frequencies.
SSDESDL	defines the target value for the desired signal strength downlink as measured by MS in different parts of the power control interval.	47 to 110 dbm	70	Lower desired SS to prevent interference in Urban Area
REGINTDL	Regulation interval, downlink	1 to 10 SACCH periods	5	Faster steps of powering up by 2 dB at 1 SACCH
SSLENDL	Length of downlink signal strength filter	3 to 15 SACCH periods	5
LCOMPDL	Path Loss compensator factor, downlink	0 to 100 %	70	When set to zero there is no power control towards SSDESDL.
QDESDL	Desired quality, downlink	0 to 70 dtqu	20	RxQual = 0
QCOMPDL	Quality deviation compensation factor, downlink	0 to 60 %	30%	When set to zero, no quality compensation is performed.
QLENDL	Length of downlink quality filter	1 to 20 SACCH periods	8
BSPWRMIN	Min allowed output power for the BTS at the locating reference point on the non Bcch freqs	-20 to +50 dbm	20

GSM Neighbor cell Parameter

Neighbor cell Parameter
Parameter	Description	Range	Ericsson Default Value	Remarks
CELLR	Related Cell designation	1 to 7 Characters	-
KHYST	Signal strength hystersis when evaluating K-cells	0 to 63db	3 dB
LHYST	Path Loss hystersis when evaluating L-cells	0 to 63db	3 dB
TRHYST	Signal Strength hysteresis for a K- and L- cell border segment	-63 to 63 db	2 dB
KOFFSET	Signal strength offset when evaluating K-cells	0 to 63 db	0	If set to 6 dB, Slower handover to CELLR
LOFFSET	Path Lloss offset when evalutaing L-cells	-63 to 63 db	0
TROFFSET	Signal strength offset for a K- and L-cell border segment	-63 to 63 db	0
BQOFFSET	Signal strength region for bad quality urgency handovers	0 to 63db	63 dB	If set to 0 dB, faster handover to CELLR
CAND	Candidate Type	AWN, NHN, BOTH	BOTH
	AWN: Neighbour at assignment to worse cell
	NHN: Neighbour at normal handover and at assignment to better cell
	BOTH: Both of the above
AWOFFSET	Signal strength region where assignment to worse cell is allowed	0 to 63 db	3 dB	3 dB -> 20 dB when Serving cell is Congested, to offload to other cell [CELLR]
HIHYST	Signal strength hysteresis when evaluating high signal strength cells	0 to 63 db	5 dB
LOHYST	Signal strength hysteresis when evaluating low signal strength cells	0 to 63 db	3 dB
HYSTSEP	Signal strength separator for high and low signal strength cells	0 to 150 dbm	90 dBm
OFFSET	Signal strength offset	-63 to 63 db	0	The parameter is represented by OFFSETN, if the value is in the range (−63, -1) dB. Positive values, (0, 63) dB, is represented by OFFSETP.

Xiaomi Continues As China's Number One Manufacturer Company

The latest smartphone sales data from Kantar Worldpanel ComTech, for the three months to July 2014, shows Chinese manufacturer Xiaomi has continued its reign over the Chinese market, holding on to the top spot with ease for the fourth consecutive month. It boasts an astounding 31.6% share of the urban Chinese market, followed by Samsung and Huawei.

Dominic Sunnebo, strategic insight director at Kantar Worldpanel ComTech, comments: "We have seen huge shifts in power in the Chinese smartphone market over the past year. Xiaomi has been the standout performer and Huawei has also seen excellent growth, while Coolpad has increased its share more modestly from 5.2% to 6.1% over the year. Considering the success of rapidly growing local brands in the Chinese market, it will be only a question of time before they seek further expansion internationally in a similar way to Huawei, and more recently Xiaomi". The same success however is not shared by all local brands such as ZTE, Lenovo and Oppo who have seen their shares come under real pressure recently.

Android has been instrumental to the success of Chinese brands, and also for smaller local European brands such as Wiko, which have helped grow Android's market leading share in Europe to 75.1%. Apple still retains second place with a 14.5% share of the market, while Windows takes third, accounting for 8.5%.

Telstra Testing LTE Using the 700Mhz Bands

Australia's Telstra saying that it has secured early access to the 700 MHz spectrum for commercial trials starting in mid September. Services will start in selected pockets of Sydney and Adelaide CBDs.

4G services on 700MHz spectrum will be rolled out in more cities and regional centres as spectrum becomes available in January 2015.

This extends the number of commercial trial cities to eight, with commercial services already being tested in Perth, Fremantle, Esperance, Mildura, Mt Isa and Griffith.

Group Managing Director Networks, Mike Wright, said the expansion of commercial trials on 700MHz is an important step in the development of this new 4G technology and will ensure telstra can provide full commercial services to its customers as soon as possible.

"In addition to faster download speeds, the use of low band spectrum like 700 MHz allows for the signal to travel further and reach deeper into buildings, improving the depth of coverage for our customers.

"Telstra also has double the holdings of 700 MHz spectrum than the other carriers, and, this combined with our existing 4G services, doubles the 4G capacity of our network in these areas, and means we can support more customers, using more devices, doing more things at the same time. This is particularly important given the continued explosion of mobile data."

The benefits of the new 4G service will be available immediately to customers using 700 MHz-ready devices A range of additional smartphones and other connected devices compatible with 700MHz 4G is expected in the coming month.

On-Demand PDCHs

General on-demand PDCH allocation as a new PSET (not for individual MS support), can be performed only in the BCCH frequency band if the parameter MBCRAC is set to 0 (default value). To allow general on demand allocation of PDCHs in other bands in a cell MBCRAC must be set to 1 or 2.

Extension of an already existing on-demand PSET is however generally allowed regardless of the MBCRAC setting.

The maximum number of on-demand PDCHs per channel group can be limited by the parameter ODPDCHLIMIT.

At allocation of on-demand PDCHs, the requested number of channels (or as many as available and allowed) are selected within the allowed frequency band(s) and subcell(s) according to the following algorithm:

1 In the case of adding PDCHs to a PSET, then select the TCHGRP where the other PDCHs in the PSET are located. Then proceed to step 10.

2 Among all TCHGRPs, select the TCHGRPs that have the best idle rank value for E-TCH.

3 Among these TCHGRPs, select the TCHGRPs that have the best idle rank value for G-TCH.

4 Among these TCHGRPs, select the TCHGRPs that have the best idle rank value for B-TCH.

5 Among these select the TCHGRP(s) that fulfils the operator chosen strategy regarding non hopping TCH on the BCCH frequency, according to parameter CSPSALLOC.

6 If the function Idle Channel Measurements is active, select among these TCHGRPs the TCHGRPs with the lowest interference level. (This refers to the channel with the highest interference level within the TCHGRP.)

7 If frequency hopping is used, select among these TCHGRPs the TCHGRPs hopping over as many frequencies as possible.

8 Among these TCHGRPs select ones in the non BCCH frequency band first, and the BCCH band as second choice if the prerequisites mentioned above will admit this.

9 If Packet Data in Overlaid subcell is used, select among these TCHGRPs the TCHGRPs in the preferred subcell according to the parameter SCALLOC.

10 Among these TCHGRPs, select the first found TCHGRP and allocate as many PDCHs as requested (or as many as possible and allowed according to the parameter ODPDCHLIMIT, if less).

Handover Power Boost

With Handover power boost (HOPB), the handover command is sent by the BSC/BTS to the MS on maximum configurative power. Handover command includes information about which uplink power the MS shall use in serving cell. The MS then acknowledges the handover command using maximum configurative power. In case of a HO failure, the HO failure message is also sent on maximum configurative power. When handover power boost is triggered, normal regulation is inhibited until the MS has received the handover command. The BTS ignores all BTS or MS power orders sent by the BSC in the serving cell until the MS has acknowledged the handover command.

The speech/channel coding and interleaving in GSM is very robust. A small number of bursts/frames can be lost without speech degradation (the number depends on the error distribution). Power Control should therefore also be used for connections close to the cell border. Since the signaling for the handover procedure (for example Handover Command) is more critical and error-sensitive, it should be sent on maximum power in order to maximise the handover performance.

HOPB is useful when the SS quickly drops, for example when the MS moves around a street corner. In this case, due to the system delay and the limited up-regulation speed, the signaling would be sent on a too low power without HOPB. Thus in order to maximise the probability of a successful handover, Handover Power Boost should be used.

Since the maximum configurative power is only used for a short time before the handover, activating HOPB has a minor impact on the overall interference level in the network.

Note that HOPB only improves the HO performance if power control is activated.

Handover power boost is activated by setting the state variable HPBSTATE.