To it tries on commercial to be to networking, a well-appointed test on last stage TD-SCDMA, it is the planning to that the network size of future further expanded at the same time, and a exploration good opportunity of problem solving, discovering the problems of network optimization and upgrading. It is a complicated system engineering that the network rule network of TD-SCDMA is excellent, it has already needed directing against slight links such as the coexistent interference with other wireless systems,etc., gradual progress staging scheduling problem of covering, outdoor wide covering, core network that and also consider the wireless indoor.
It is the most important thing that wireless partial planning is optimized
By the look of TD-SCDMA wireless network, at present, technical development such as base station, aerial are very fast, and can update according to the request of operator, has made very great progress in commercialization. The staging of base station is optimized and developed towards low cost, high capacity, apt expanding, serial products of high reliability, zooming out the base station becomes major application. The zooming out base station integrates the module or group tape cell of radio frequency to the tower in the unit, have solved the problem with many wire. The miniaturization of the base station has already become the trend, it has saved the computer lab, day Taxi space, have reduced the bearing to require, help the project to be installed; Reduce the difficulty of the project, shorten time limit, can construct the masterpiece network more fast, let the network come into operation faster. In addition, the difficult problem of selecting the site to the base station, many manufacturers have introduced the concept of the modularization base station. In this way, when the wireless network expands, the operator can expand the capacity based on module, use the identical module no matter it is a macro-base station or little base station, does not need to prepare different spare parts for the demand for different station site. Because the environment that the wireless network disposes is more complicated, the requirement on the project is numerous, the apparatus had introduced the seriation base station of meeting different application scenes one after another recently in Shang. Base station these combine other auxiliary facility, can realize the intersection of signal and covering with while being good under various environment. To the network overlapping of the special scene, it is covered, moved and covered, covered etc. in the subway at a high speed for example wide in the sea area, every apparatus manufacturer has launched deep research too. TD-SCDMA Smart antennas designs holding and generating electricity to adjust the aerial, fretwork aerial, miniaturize the aerial and beautify products such as aerial and multi system block antenna,etc. progressively too, a large number of products are applied to the try net already.
From the viewpoint of planning of wireless frequency, the planning of TD is very characteristic too. In TD system, what we adopt at present is N frequency point technology, the expert introduces, as to the planning of its resource of frequency, probably have the following several main point needing to pay attention to. First of all, if the intersection of frequency and the intersection of resource and sufficient, the same Residential Area should adopt first up to and unify frequently. At present, in the apparatuses of some producers, already an algorithm frequently has appeared. And with the further enlargement of the network, appearance that and the large-scale indoor is covered, it is more scientific to need our planning, rational utilization of frequency resources. For example, on the Off-The-Shelf frequency point, the network builder has already begun to face the severe challenge in this respect, especially the cover like such large-scale venue of bird nest, the science of frequency resources plans to seem more urgent. Meanwhile, the frequency is planned will also bring the changes of cost of power amplifier and characteristic, and a lot of associated problems are all pressing problems that we face next.
From the viewpoint of wireless technology upgrading, TD network still faces the challenge to HSPA network of the staging within short time, how the indoor covering system guarantees the smooth transition, need to consider a lot of questions, for example, how to regard guaranteeing the edge of object design HSDPA business speed is required as and cover field intensity? How to plan a lot of carrier powers? HSDPA uses QPSK and 16QAM adaptation modulation mode, should it be to bringing the higher requirement put forward linearly for the amplifier from this how? All these are worth our contemplating.
In addition, with completion of different 3G rules such as TD, we also have interference problem coexisting systematically more. For example, PHS system is a master interference source of adjacent place of 2GHz frequency band, PHS various early base stations reach - about 45dBm/1.6MHz in the stray value of 2010MHz- 2025MHz frequency band, so TD networking must be considered with the coexistent interference problem of PHS system, and with TD large-scale and commercial arrival, this kind of interference problem will be prominent day by day.
The core network develops and moves forward steadily
By the look of TD-SCDMA core network, IP of the network has already become a kind of inevitable direction. Because TD-SCDMA core network technology is basically identical with WCDMA, this makes the development route of TD core network keep unanimity with WCDMA. Before this, in 10 TD-SCDMA external field test which cities carries on in China, the operators all adopted with WCDMA totally concerted core network without exception. In core network, TD-SCDMA and WCDMA adopt the all the same standard specification, including adopting the same Iu interface between core network and radio network, and the air interface high layer protocol is all the same. The something in common has guaranteed conformance and QoS of seamless roaming, switching over, business support between two systems are ensured etc., also guaranteed TD-SCDMA keeps equivalent conformance with WCDMA in the technical subsequent development of the standard. In addition, according to moving operator's core network and disposing the soft interchange system, performing to progress with whole that of the network too cuts down and keeps unanimity. The expert introduces, TD-SCDMA core network test equipment has adopted R4 edition, the apparatus manufacturers of TD mainstream have all put out the complete TD-SCDMA core network solution. So the operator can realize the putting in the network connection in right place in one step of construction of core network, establish technological advance, the staging of the core network can move forward to optimize steadily.
Ancillary equipment such as testing tool, planning software are developed synchronously
Compared with two kinds of other 3G systems, TD-SCDMA network has some technological characteristics, such as the frequency point of time-division duplex, Smart antennas, N, one yard of resources planning, dynamic channel allocation (DCA) , relay switch over, make TD planning and optimization of network with different to some extent in the past, need us through some new testing and design tools. So, the test / emulation tool, instrument,etc. of TD are becoming a key apparatus of this field progressively. For example, at present, China communication standardized association (CCSA) Having already made a series of artificial mechanism of theory that has coexisted systematically more, TD-SCDMA network planning tool leads these mechanisms into gradually too, look for the simple practical emulation method, the unfavorable situation avoided the true cloth network, redesigned because of intersystem interference.
In addition, not merely traditional network planning optimizes the method to change to some extent with TD promotion of networking, to cover the scheduling problem as to the important field indoor of 3G network optimization, the expert thinks unanimously, work optimally more compared with the indoor that rely on experience and limited test to carry on ambiguity, use the network planning software of indoor obviously in order to have efficiency scientifically and even more, but the indoor network planning software product that can offer on the market at present is not abundant enough, the characteristic still remains to raise too, builder's demand in this respect of the network will be stronger and stronger in the future. In the network planning of indoor at present, the engineer often adopts the model based on logarithm of the distance, this model is no doubt simpler, easy to design, can calculate manually and draw, but the error is relatively great. Especially when the BLDG is more complicated, will need to use the more accurate model, if use the indoor to plan the software, can employ the appropriate model according to the situations of floor and multi-layer wall very relaxedly, reach good emulation and simulation result. But if can join some functions more, for example carry on emulation to outdoor leakage to the indoor signal, for example combine the software of outdoor planning and indoor planning together and do, then the software of network planning will produce enormous utility.
Source: CHINAUNICOM website