Multi-MNC

I. Overview

The multi Mobile Network Code (multi-MNC) function allows the operator to configure the cells which have different MNC in one BSC.

II. Technical Description

1) System message processing

The system sends different system messages including different MNCs respectively to the multi-MNC cell and the normal cell, and then an MS can display the mobile network name it subscribes to as per the system message. (The BSC contains the same Cell Global Identification (CGI) for a cell as the MSC does if the MSC supports a multi-MNC cell. In this case, the BSC need not use the multi-MNC function parameter).

The multi-MNC function is applied when two or more network operators are integrated or when some small operators rent equipment from a large operator. See Figure 2-42.

A-MSC

A-BSS

Cell 1: 460 12 1850 0001 Cell 2: 460 34 1810 0002 T

R X 1

T R X 2

MS Display: 12 MS Display: 34

B-MSC

Operator A: MNC = 12 Operator B: MNC = 34

Figure 2-42 Multi-MNC diagram

In this document, a multi-MNC cell is a cell whose CGI includes a MNC different from the MNC configured in the [Local Office Information Table].

2) Handover strategy

System provides flexible handover control means. In different situations, mobile phones can be handed over to a cell with the same MNC or a cell with a different MNC.

There are seven handover control means provided: normal handover, only the handover to a cell with the same MNC allowed, a cell with the same MNC first, a better cell with the same MNC first, a better cell with a different MNC first, a cell with a different MNC first, and only the handover to a cell with a different MNC allowed.

Select a suitable multi-MNC handover control type according to the actual situation.

The following will give an introduction to the control strategy and the possible applicable situation of each handover type.

In the situations where multiple MNCs are used, configure "Multi-MNC handover judgement allowed" with "Y". "Multi-MNC handover type" can be configured with the expected types according to the actual requirements.

The control strategy and applicable situation of each handover type are as follows:

a) Normal handover

Control strategy: Handover to a cell with better QoS (considering all such factors as

Applicable situation: The situations where mobile phones are expected to be handed over to a cell with better QoS. Not considering whether the object cell has the same MNC or a different MNC.

b) Only the handover to a cell with the same MNC allowed

Control strategy: Only the handover to a cell with the same MNC is allowed, including the service cell.

Applicable situation: The situations where mobile phones are expected to be handed over to a cell in the same network.

c) A cell with the same MNC first

Control strategy: As long as the adjacent cell has the same MNC with the service cell and the received level is higher than "minimal downlink power of candidate handover cell" of this adjacent cell, mobile phones will be handed over to this adjacent cell, including the service cell.

Applicable situation: As long as a cell in the same network can provide normal services, mobile phones are expected to be handed over to this cell. When mobile phones cannot be handed over to a cell in the same network (for example, no signal can be detected in a cell with the same MNC), they can be handed over to a cell with a different MNC.

d) A better cell with the same MNC first

Control strategy: If the adjacent cell and the service cell have the same MNC and the received level of the adjacent cell is higher than the inter-layer handover threshold of this adjacent cell, mobile phones can be handed over to this adjacent cell, including the service cell.

Applicable situation: When a cell in the same network can provide good services (i.e., higher than the inter-layer handover threshold), mobile phones are expected to be handed over to a cell in the same network. If no cell that can provide good services is available in the same network, mobile phones will be handed over to a cell with the better QoS, regardless of whether the object cell with the same MNC or a different MNC.

e) A better cell with a different MNC first

Control strategy: If the adjacent cell has a different MNC from the service cell and the received level of the adjacent cell is higher than the inter-layer handover threshold, mobile phones will be handed over to this adjacent cell.

Applicable situation: When a cell with a different MNC from the service cell can provide good services (i.e., higher than the inter-layer handover threshold), mobile phones are expected to be handed over to this cell. If no cell that can provide good

services is available in other networks, mobile phones will be handed over to a cell with the better QoS. If there are only a few cell channels in this network but the coverage is satisfied, this control strategy can be selected in case of congestion and if traffic sharing is allowed in other networks.

f) A cell with a different MNC first

Control strategy: As long as the adjacent cell has a different MNC from the service cell and the received level of the adjacent cell is higher than "minimal downlink power of candidate handover cell", mobile phones will be handed over to this adjacent cell.

Applicable situation: As long as a cell in another network can provide normal services, mobile phones are expected to be handed over to this cell. When mobile phones cannot be handed over to a cell in another network (for example, no signal can be detected in this cell), mobile phones can be handed over to a cell with the same MNC.

If there are only a few cell channels in this network but the coverage is satisfied, this control strategy can be selected in case of congestion and if traffic sharing is allowed in other networks.

g) Only the handover to a cell with a different MNC allowed

Control strategy: Only the handover to a cell with a different MNC is allowed.

Applicable situation: Mobile phones are expected to be handed over only to a cell in another network.

3) Application note

a) The CGI allocated by the MSC to a normal cell should include a LAC different from the LAC in the CGI the MSC allocates to a multi-MNC cell.

b) The MNC in the [Local Office Information Table] at the BSC side should be the same as the MNC configured at the MSC side. At the BSC side, the cell CGI is configured as the CGI over the Abis interface of the local BSC and the external cell CGI as the CGI over the Abis interface of the peer BSC. There should be only one difference between the multi-MNC cell CGI configured at the BSC side and the corresponding CGI at the MSC side i.e., different MNCs.

c) For a BSC with the multi-MNC function, inter-BSC handover can be implemented only when the peer BSC is also designed as multi-MNC function supportable.

d) The multi-MNC cell cannot support GPRS services presently and the normal cell can.

III. Parameter

2.2.16 E-GSM/R-GSM

I. Overview

Along with the development of GSM in a large scale, the frequency resource becomes more and more insufficient and bottlenecks the further development of GSM. The current solution is to introduce new frequency bands. The introduction of E-GSM and R-GSM extended bands plays an important role in solving the shortage of frequency resource.

II. Technical description

According to GSM 05.05 (version 8.5.0), there are four frequency bands:

1) GSM900 base band, P-GSM:

The working frequencies of the GSM900 baseband are:

890 ~ 915MHz: For mobile phone sending and BTS receiving.

935 ~ 960MHz: For BTS sending and mobile phone receiving.

2) GSM900 extended band, E-GSM (including GSM900 base band):

The working frequencies of GSM900 extended band are:

880 ~ 915MHz: For mobile phone sending and BTS receiving.

925 ~ 960MHz: For BTS sending and mobile phone receiving.

3) GSM900 railway band, R-GSM (including GSM900 base band and GSM900 extended band):

The working frequencies of R-GSM900 are:

876 ~ 915MHz: For mobile phone sending and BTS receiving.

921 ~ 960MHz: For BTS sending and mobile phone receiving.

4) DCS1800 band:

The working frequencies of DCS1800 band are:

1710 ~ 1785MHz: For mobile phone sending and BTS receiving.

1805 ~ 1880MHz: For BTS sending and mobile phone receiving.

The internal between frequencies is 200kHz.

The relations between frequency points and absolute frequencies are as follows. n:

frequency point. Fl(n): uplink frequency corresponding to n. Fu(n): downlink frequency

Table 2-17 Table 1 Relations between frequency points and absolute frequency

P-GSM 900 Fl(n) = 890 + 0.2*n 1<= n <=124 Fu(n) = Fl(n) + 45 E-GSM 900 Fl(n) = 890 + 0.2*n 0<= n <=124 Fu(n) = Fl(n) + 45

Fl(n) = 890 + 0.2*(n-1024) 975<= n <=1023

R-GSM 900 Fl(n) = 890 + 0.2*n 0<= n <=124 Fu(n) = Fl(n) + 45 Fl(n) = 890 + 0.2*(n-1024) 955<= n <= 1023

DCS 1800 Fl(n) = 1710.2 + 0.2*(n-512) 512<= n <= 885 Fu(n) = Fl(n) + 95

The newly introduced E-GSM 900 band and R-GSM 900 band belong to the same band with P-GSM. However, the frequency points are not continuous. Therefore, the E-GSM extended band and R-GSM extended band are introduced. The E-GSM