• Concentric Cell Parameter Setting

Overview:

The Concentric technology divides ordinary cells into two service layer: big subcell and small subcell. For mobile phones within the big subcell, the frequencies of sparse frequency reuse will be preferably allocated (such as BCCH frequency), while for mobiles within the small subcell, the frequencies with dense frequency reuse will be allocated as much as possible (such as non-BCCH frequencies). The system capacity can be efficiently improved by the dense reuse pattern of frequencies within the small subcell. As shown in the following figure, the mobile phone within the small subcell is quite far from the interference source, so although the dense reuse frequency is used, the voice quality can still be guaranteed. For the mobile phone within the big subcell, since the sparse reuse frequency is used, the voice quality can also be guaranteed.

If the underlaid subcell is underlaid with the overlaid subcell or underlaid subcell of another cell, then the MS in the underlaid subcell can be directly handed over to the other cell. Thus, the congestion of the overlaid subcell can be efficiently mitigated.

The Concentric technology has divided the cell coverage area into the underlaid subcell and overlaid subcell so that different frequency reuse pattern can be used for TRXs of the underlaid and overlaid subcells respectively.

Recommended Parameter and Value: 

Concentric Cell Parameter Setting
No	Param Name	Value
1	Enhanced Concentric Allowed	Yes
2	Concentric Circles HO Allowed	Yes
3	UL to OL HO Allowed	Yes
4	OL to UL HO Allowed	Yes
5	RX_LEV for UO HO Allowed	Yes
6	RX_QUAL for UO HO Allowed	No
7	TA For UO HO Allowed	No
8	RX_LEV Threshold	35
9	RX_LEV Hysteresis	5
10	RX_QUAL Threshold	60
11	Assign Optimum Layer	System Opimization
12	Assign-optimum-level Threshold	30
13	Pref. Subcell in HO of Intra-BSC	System Opimization
14	Incomming to BSC HO Optimum Layer	Underlaid
15	OtoU HO Received Level Threshold	20
16	UtoO HO Received Level Threshold	30
17	UtoO Traffic HO Allowed	Yes
18	En Iuo Out Cell Low Load Threshold	20
19	En Iuo Out Cell General OverLoad Threshold	70
20	En Iuo Out Cell Serious OverLoad Threshold	80
21	Enhanced TCH Adjust Allowed	No
22	IntraCellHo to Ass SWITCH	Yes
23	Support Half Rate	Yes
24	TCH Rate Adjust Allow	Yes
25	Busy Threshold of TCH Traffic in Overlaid Subcell	10
26	Tch Traffic Busy Underlay Threshold	10
27	Allow Rate Selection Based on Overlaid/Underlaid Subcell Load	Yes
28	AMR TCH/H Proir Cell Load Threshold	10
29	Load HO Allowed	Yes
30	Load HO Threshold	95
31	Load Req.on Candidate Cell	85
32	TRx Priority	Level 0
33	GPRS service	Enable