GPRS Network optimization: 3g knowledge

GPRS network optimization is more complicated than GSM network optimization. GPRS system with GSM network as the bearer network, using the existing GSM wireless network, GPRS and GSM share the same base station and spectrum resources, which determines the GPRS network and GSM network optimization exist interrelated and mutually restricted relationship.

First of all, GPRS network optimization and GSM network optimization in general is consistent. Because GSM network is the carrier network of GPRS, it is very important to optimize the GSM wireless environment for GPRS optimization. Lifting the network overall load ratio can improve the GSM network call quality, at the same time can make more GPRS mobile phone enjoy advanced coding scheme, improve the system throughput, further reduce the ratio of packet retransmission, so that the actual data transmission rate to the highest.

Secondly, there is conflict between GPRS network optimization and GSM network optimization. The new interference introduced by GPRS, to a certain extent, it will lead to a decline in the quality of calls, switching off the rate of increase, resulting in the original voice service area narrowed; because they use the same frequency band resources, there are conflicts in the capacity configuration, GPRS, such as the use of ccch on the way, CCCH load will have a greater increase Because GPRS introduces flexible voice and data channel allocation strategy, wireless resource scheduling becomes more complicated, which leads to the increase of switching times, and also has a certain influence on the success rate of the original network and the success rate of handoff. When the GSM network optimization and GPRS network optimization conflict, at this stage should be based on voice, that is, in order to ensure the quality of GSM network, as far as possible to improve the quality of GPRS service.

At the same time, GPRS network optimization has its own characteristics, GPRS business model and GSM different, so the traffic volume/data volume prediction methods, empirical formulas exist different, GPRS coverage and GSM is not exactly the same, GPRS data service coverage probability, The signal loading and drying ratio and the capacity of the proposed higher requirements. In the process of network optimization, we should grasp the common points of two networks to focus on optimization, for the conflict between the two places, taking into account the development of different periods of network under the premise of maximizing the benefits as the goal of the two network to balance. (Computer science)

The optimization principle of GPRS network

Because the GPRS network is built on the GSM network, its service quality is closely related to the GSM network's index, the congestion degree of GSM network, the quality of the wireless network and the parameter setting of the idle state will affect the user's GPRS perceived performance such as traffic. Based on the complexity of GPRS network, the optimization principle of GPRS should be expounded from three aspects of capacity, disturbance and mobility.

1. Capacity

GPRS is the use of the free resources of GSM network to provide services. GPRS occupied by the wireless channel resources have dedicated PDCH and random pdch, because the voice business priority in the data business, if the community does not set the FPDCH, when the tch congestion will not have GPRS services, is in the GPRS business will also stop, the pre-emptying event will occur, The data to be passed in the PCU will be discarded. If the community set up Fpdch,cs business congestion will not cause the stop of GPRS business, but the user's throughput will be affected, the extent of the impact depends on the number of GPRS traffic and FPDCH. Because the GPRS handset decides the choice of the district, cannot like the voice service to be assigned to the worse community, therefore the Congestion cell's GPRS service perception performance will be affected.

In view of the current GPRS business to small data-oriented development, it is more sensitive to congestion, but the number of time slots are not sensitive, so each cell configuration 1 FPDCH can be, while the Tbfullimit, tbfdllimit configuration for 2. For the analysis of STS, TEMs Road test and GB interface signaling, it is found that some community resources are insufficient and there are more pre emptying events, which can be rationally shared with GSM traffic volume by parameter adjustment, and increase FPDCH or enlarge the capacity appropriately.

2. Interference

Network and network interference is the problem that all wireless communication technology faces. The impact of interference on network quality is mainly reflected in the air interface information is distorted or destroyed, in the receiver difficult to restore, to GSM means the quality of the voice down, GPRS means the wrong packet retransmission, that is, flow (throughput) decline. If the interference time is too long, it may cause service interruption.

At present, the GPRS network of users, small traffic, the interference caused by the total amount of interference is very small, the proposed stage does not open the uplink dynamic Power control GPRS, that is, gamma=0, alpha=0, in GPRS there is no downward dynamic power control. GSM interference is usually the main source of GPRS interference, take more radical dynamic power control parameter configuration, combined with the use of DTX, hop can reduce interference in the network.

The uplink interference can be found by ICM Measurement and MRR, and can be adjusted by using FAs to help adjust the frequency point or the change of the angle of the antenna and the direction of the antenna. The downlink interference can be found by MRR, TEMs Road measurement or fixed-point measurement, which can be solved by frequency adjustment, parameter modification or overlay adjustment. For foreign interference, we should try our best to find and eliminate them.

3. Mobility of

In the GPRS network, the district re-election and the lack of resources and wireless environment will result in the decrease of throughput, and increase the delay; The district re-election will also occupy more RPP resources and make the PCU resource shortage. Frequent cell re-election has a serious impact on static users or fast moving users at the edge of the cell, but too much CRH or CRO may cause more interference and decrease in flow rate.

In the current network configuration, GPRS mobile phone for cell selection/re-election follow the C1/C2 algorithm, but with the GSM is different: in the ready state, CRH role in all communities, as the cell re-election hysteresis, control unnecessary cell re-election, in the GPRS network is the key to mobile performance. Due to the current lack of mobile counters, improve this performance, road test is a more effective way, through the road test to find the problem, after careful analysis, combined with the performance of GSM statistical analysis, the adjustment of the parameters of the cell gravity, covering the parameters of the adjustment or antenna pointing adjustment.