3 Customer Value ....................................................................................................................... 5 3.1 Improving the network capacity..................................................................................................................6 3.2 Improving the network quality....................................................................................................................6
2009-3-26
Huawei Confidential
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White Paper for the GSM BSS IBCA Solution
Confidentiality: INTERNAL
White Paper for the GSM BSS IBCA Solution
1
Background In the GSM network, as frequency resources are scarce and operators can use only the limited frequency resources, many kinds of technologies, such as frequency hopping, are used to improve the frequency utilization. To reduce interference and improve the network quality, Huawei has launched the Interference-Based Channel Assignment (IBCA) function, which can obviously improve the frequency utilization and network capacity.
2
Huawei IBCA Solution Huawei IBCA solution is based on synchronized BSS Network. The BSC estimates the carrier-to-interference ratio (C/I) of the idle channels and interference to the server channels, then assigns an idle channel that meets the C/I requirement to a call. The assignment of the new channel does not cause any unacceptable influence on the existing calls. The IBCA algorithm comprises two processing procedures. One is C/I estimation and the other is optimal channel assignment. In the C/I estimation procedure, the system combines the measurement report and history measurement report information to estimate the C/I of the new call and how the new call influences the C/I of the existing calls based on the MAIOs that can be allocated to the new call. In the optimal channel assignment procedure, the system ultimately selects an MAIO that can both meet the requirements of the new call and least affect the existing calls based on the C/I estimation results of various MAIOs.
2009-3-26
Huawei Confidential
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White Paper for the GSM BSS IBCA Solution
Confidentiality: INTERNAL
2.1 C/I Estimation The signal of a call is a valid signal for the call itself but an interference signal for all the other calls. Co-channel interference or adjacent channel interference occurs when two calls use the same frequency or use two adjacent frequencies. When the interference reaches some value, it will greatly influence the network quality. To avoid serious influence to the network, the C/I should be estimated before the channel is allocated for the call. The C/I estimation procedure is described as follows: a
Confirm the interference channels: Based on the frequency hopping-related parameters adopted by the new call and the existing calls, confirm the interference channels if some certain frequency was assigned for the call.
b
Calculate the interference signal strength for the existing calls with which the new call will interfere.
c
Calculate the C/I of the new call.
d
Calculate the C/I of the existing calls.
e
Calculate the C/I value after comprehensive estimation.
2.2 Interference-Based Channel Selection After completing the C/I estimation, the system checks all the idle timeslots in the cell and selects one timeslot whose C/I value is the best according to the comprehensive estimation results. The system allocates this timeslot and the corresponding MAIO to the new call meanwhile to insure the quality of the network.
3
Customer Value Huawei IBCA function is recommended when the frequency resources are scarce, the traffic is high, and severe interference exists and cannot be solved by frequency hopping. In such scenarios, the network will get much more benefits for the capacity and more efficient frequency utilization of the network when IBCA is adopted. The IBCA will be carried out by Huawei GBSS8.1 and the system only needs software upgrade without any additional hardware.
2009-3-26
Huawei Confidential
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White Paper for the GSM BSS IBCA Solution
Confidentiality: INTERNAL
3.1 Improving the network capacity The unique IBCA arithmetic of Huawei can improve both network quality and capacity under the limitation of frequency resources. Thus IBCA can greatly improve the reuse of limited frequency, especially under the situation of low capacity, high traffic and frequency hopping can not improve much.
3.2 Improving the network quality Because the IBCA takes into account the interference to the existing calls before assigning channels to each call, it improves the call quality. The IBCA function improves the wireless-related KPIs, such as voice MOS, call drop rate, and traffic.
2009-3-26
Huawei Confidential
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