GSM Frequency Planning

After learning this courseyou canMaster the basic concept of GSM frequency planningMaster various patterns and principles of frequency reuseMaster the principle and approach of neighbor cell planningMaster the principle and approach of BSIC planningKnow the familiar anti-jamming technologyCourse target

Frequency planning summarizeFrequency reuse patternAdjacent cell planningBSIC planningAnti-jamming technologyIndex

The status and function of GSM frequency planning in wireless network planningImpact network capacity and base station configureinterfere anticipating and simulatingThe status and function of GSM frequency planning in network optimizationDepress the interfere, improve C/I, improve call quality Optimize frequency resourceImprove manage valueThe importance of GSM frequency planningA important content of network planning A important means of network optimization

Frequency planning summarize

Effect of frequency plannning

Frequency planning summarizeGSM system frequency spectrum

Frequency planning summarizeChannel number of GSMChannel intervalEach carrier occupies 200KHZ,use TDMA, include 8 physical channelsChannel configureGSM900MHz frequency bandfu(n)=890.2MHz+(n-1)*0.2MHzfd(n)= fu(n)+45MHzGSM1800MHz frequency bandfu(n)=1710.2MHz+(n-512)*0.2MHzfd(n)= fu(n)+95MHzfu(n)uplink frequencyMobile station sendbase transceiver station receivefd(n)downlink frequency base transceiver station sendmobile station receive

Frequency planning summarizeForm regulation of Cell structureWireless cell clusters should be adjacent with each other 2) The centre distance of arbitrary two same frequency reusing area in adjacent wireless cell clusters should be equal

Frequency planning summarizeSame frequency interfere ,C/IMeaning of C/I : when different cells use same frequency, anther cell will cause interfere, the ratio between them is C/I.In GSM criterion ,it usually request C/I>9dBin engineering, usually add 3dB marginso get C/I>12dB.Adjacent frequency interfere ,C/AMeaning of C/A: In the model of frequency reusing ,the adjacent channel will cause interfere to the channel of serving cell. The ratio between two signals is C/AIn GSM criterion, usually request C/A>-9dB.Definition of same frequency and adjacent frequency interfere

The calculating about C/I of same and adjacent frequency Frequency planning summarize

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Model of same and adjacent frequency interfereFrequency planning summarize

When reuse the frequency regularly The centre distance of arbitrary two adjacent same frequency reusing area is D, therefore, arbitrary three adjacent same frequency reusing area compose a equilateral triangle .From the chatwe can see thatThe first circle has 6 disturbersthe second has 12.

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Frequency planning summarizeFrequency planning stepsystem data collectcheck the integrality of the dataDo the planning according to the decided pattern of frequency reuseBCCH planningAnalysis and forecasting of the system interfereSatisfy the planning request Export the reportSwitch relation planningTCH planningBSIC planningHSN planning

Frequency planning summarizeFrequency reuse patternAdjacent cell planningBSIC planningAnti-jamming technologyList

Frequency reuse:It means reusing the same frequency in digital cell system. Usually, we divide the frequency into several teams. These frequency clusters which formed in turn then are distributed to adjacent cells Frequency reuse patternFrequency reuse

Several concepts about frequency reuse Frequency reuse Decided by the restrict of the frequency resource Make use of the same frequency team to cover different area, the frequency of the reusing is expressed by the reuse ratio. Same frequency reuse distance Areas ,that use the same frequency should space out certain distance, which is called Same frequency distance D. interfere protecting ratio same frequency interfere protecting ratio C/I9dBusually, add 3dB margin in engineeringso C/I>12dBadjacent frequency interfere protecting ratio C/I 9dB usually, add 3dB margin in engineeringso C/A>-6dB 400KHz adjacent frequency interfere protecting ratio C/I41dBFrequency reuse pattern

Standard frequency grouping reuse technologyMulti-frequency reuse technologyCompact frequency reuse technologyMulti-layer network technologyConcentric circle technologyConstruct GSM900/1800 dual frequency netGrouping frequency reuse patternFrequency reuse pattern

43 reuse example of 43 reuse 1The telecom carrier has 7.2M bandwidth36 carrierstake use of 43 frequency reusing patternFrequency reuse pattern

43 reuse example of 43 reuse: Adjacent base stations dont have the same frequency, but till has the phenomena that adjacent cells have the same frequencypattern1D1---A2pattern2D2---A3pattern3D1---A2pattern4D2---A3pattern5D3---A1pattern6D3---A1

Frequency reusing pattern

Example of 43 reuse 2The telecom carrier has 7.2M bandwidth36carrierstake use of 43 frequency reusing pattern43 reuseFrequency reuse pattern

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43 reuse example of 43 reuseExcept the case 14other cases have the problem that the adjacent frequency do face to face each otherpattern2C1---A2pattern3B2---A3pattern5C1---A2B2---A3D3---A1pattern6D3---A1

Frequency reuse pattern

33 reuse 33 reuse 33 reusing definition: Divide the frequency into nine teams and then distribute them to three base stations in turn, namely, each station has three frequency teams. C/IFrequency reuse pattern

33 reuseExample of 33 reuseThe telecom carrier has 7.2M bandwidth36 carrierstake use of 33 frequency reusing patternFrequency reuse pattern

A1B1C1A2B2C2A3B3C3123456789101112131415161718192021222324252627282930313233343536

33 reuse example of 33 reusepattern1no existing the phenomena that the cells facing each other have adjacent frequency.pattern2C1---A2;C2---A3;C3---A1Frequency reuse pattern

13 reuse 13 reuse 13 reusing definition: divide the frequency into three teams and then distribute them to one base station, namely,each station has three frequency teams. C/IFrequency reuse pattern

13 reuse example of 13 reusingThe telecom carrier has 7.2M bandwidth36 carriersBCCH use 43 reusingTCH use13 reusing + RF hoppingFraction Load considered with 50%BCCH and TCH use one separated frequency. Suppose the CA of TCH is 1-23.Make sure that MAIO of three cells should not be adjacent in the same base station keep MIAO of same direction cells in each base station consistentKeep HSN of three cells in the same base station same HSN of adjacent base station should be differentthe distance of base stations which have the same HSN should keep as far as possibleHSN reuseFrequency reuse pattern

MA11471013161922MA22581114172023MA336912151821

MRP MRPDefinition of MRP( Multiple Reuse Pattern ):divide the whole frequency section into BCCH sections which quadrature witn each other and several TCH sections , each section is a independent layer. Frequency in different layer is used with different reusing pattern, frequency reusing is compact layer by layer.

Frequency reuse pattern

MRPFrequency reuse pattern

MRP example of MRPThe telecom carrier has 7.2M bandwidth, have 36 carriersthe frequency number is 60-95use Multiple Reuse PatternMRP,divide 36 carriers into four teams by the way of 12/9/8/7.

Frequency reuse patternuu

1) BCCH 4 32) TCH1 3 34) TCH3 2 33) TCH2 2 3MRPFrequency reuse pattern

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MRPFrequency reuse pattern

concentric circledivide common cell into two layersinner layer and outer layer.Concentric circle Frequency reuse pattern

Concentric circleFrequency reuse pattern

cell splitting

necessaryinitial construct time of GSM net work user numbers is small user number increase channel congestion enlarge carrierUser number increases channel congestion and frequency saturation cell splitting

characteristicSplit one timethe cover radius of site is half then primary.The number of site is four times than primaryCan not split infinitely.Cell splittingFrequency reuse pattern

According to the adopted frequency reuse pattern and available bandwidth of the GSM network in planning area ,we can get the maximum carriers that can be configured in a base station.According to the number of voice channel and target of call congestion rate, by checking the Erlang-B table, we can the maximum traffic that each site can support .According to site minimum radius, we can get maximal traffic density that a site can afford under current frequency reuse pattern.Compare above value with the traffic density which should be afforded in high traffic density area, if the anterior value is small than the latter one, it means that current frequency reuse pattern cant afford the capability need of users. So must use more compact reuse pattern and then ,repeat above steps. Ascertain the frequency reuse pattern in planning area finally.Ascertain the approach of the frequency reuseFrequency reuse pattern

Collectivity principle of frequency planningFrequency reuse pattern

GSM900 macroGSM1800 macroGSM900 microGSM1800 microP-cellP-cellMulti-layer network technologyFrequency reuse pattern

Frequency planning summarizeFrequency reuse patternAdjacent cell planningBSIC planningAnti-jamming technology

Collectivity principle of adjacent cell planningAdjacent cell planningCollectivity principle of adjacent cell planning:Main cell and adjacent cell cant have the same frequencyThe number of adjacent cells cant exceed 32

Adjacent cell planning principle in urbanAdjacent cell planning

Adjacent cell planning principle in sub-urbanAdjacent cell planning

Irrationality type of adjacent cell planningSingle direction adjacent cellAdjacent cell overfullAdjacent cell too lessInduce problemsCall dropSwitch failureHigh frequency switchIsolated islandForeign abnormity switchTraffic imbalanceLow the switch precisionThe irrationality problems in adjacent cell planningAdjacent cell planning

Frequency planning summarizeFrequency reuse patternAdjacent cell planningBSIC planningAnti-jamming technology

value range of BSIC NCC07 BCC07The definition and value range of BSICBSIC planning definition of BSIC NCCnetwork color code BCCBTS color code

Effect of BSICBSIC planning

Principle of BSIC planningBSIC planning

Frequency planning summarizeFrequency reuse patternAdjacent cell planningBSIC planningAnti-jamming technology

Frequency Hopping FH Dynamic Power Control DPCThe measure of anti-jammingAnti-jamming technology

Frequency hopping

Base Band Hopping

Synthesize HoppingFrequency hoppingAnti-jamming technology

Base band hoppingAnti-jamming technology

Synthesize hoppingAnti-jamming technology

Several important parameters of HF hoppingAnti-jamming technology

frequency diversityresist Rayleigh fadingAdvantages of frequency hoppingAnti-jamming technology

Interfere diversityinterfere averageAdvantages of frequency hoppingAnti-jamming technology

Thank you !

BCCH can use 4 3 or higher reuse factor to ensure the quality of the BCCH channel; TCH and is relatively close to use reusable way; BCCH, TCH band on each floor of the separation of planning to reduce the workload can be layered planning; can also separate a section reserved for micro-cellular frequency; BSIC decoding and voice channel capacity has nothing to do. As the BCCH and TCH band orthogonal frequency, TCH channel to increase the load on the BCCH does not affect the basic channel, so it will not affect the BSIC decoding, so as to improve the performance of switching; Simplify the neighboring district of the table configuration. Documents relating to that area adjacent table would be too long to switch to lower performance, this method can simplify the adjacent cell table, so as to improve the performance of switching; BCCH due to the use of a separate section of the frequency (4 3 under way with 12 points, frequency), the neighboring district table (BCCH by the frequency etc.) can significantly reduce the length; Real power to control and anti-jamming technology, such as DTX. BCCH can not use dynamic power control, such as DTX and technology, it is always with the greatest launch in the signal transmitting power. Therefore, BCCH and TCH use the same frequency band, which will affect the effectiveness of anti-jamming technology; BCCH, TCH at all levels of relatively independent, easy to maintain and expand the stratification. By, or delete sites of the district TRX, the BCCH does not have an impact on frequency planning in order to facilitate the maintenance of the network. Concentric circles is the so-called common area is divided into two regions: the inner and outer layer, also known as top-level (Overlay) and bottom (Underlay). The outer layer of coverage is the traditional cellular area, and the inner layer of coverage concentrated in the vicinity of the base station. The difference between the inner and outer In addition to the different coverage, frequency reuse factor they are also different, generally the outer traditional 4 3 multiplex mode, and the inner layer is used closer reuse, such as 3 3,2 3 or 1 3. Therefore, all the carrier channel has been divided into two groups, one group for the outer, inner layer for a group. The reason why such a structure known as the concentric circles, because the outer and inner layer is a total site, and a set of common antenna system, sharing the same channel BCCH. But the public must belong to the outer Channel Channel team. This means that the call must be set up in the outer channel to carry out. General concentric circles: do a good job in network planning. On the one hand, attention focused on the application of traffic areas, on the other hand, the inner layer of the planned coverage area, that can not be reused because of close and bring the quality of interference effects, but also be able to absorb enough traffic. If the planning is not good, not only do not seek to increase capacity, may also lower the quality of the network; the best combination of technologies used to reduce interference, such as power control, DTX, and so on. Smart concentric circles: Planning to do a good job. Area planning should be based on traffic distribution, and to reduce interference with the attention. In small channel allocation should pay attention to the frequency of super-group and conventional group of the rational allocation of frequencies. To the bottom of sufficient capacity to absorb and reduce dropped calls, it is necessary to pay attention to set up small parameter. In order to reduce interference should be a combination of power and control for the launch (DTX) technology. In the best of conventional layer is also based on C / I of the switch. The same base station within the same can not be adjacent channel. The direct vicinity of the base station to avoid the same frequency (even if its main antenna valve in a different direction, side-lobe back flaps and the impact will be greater interference); The same can not be small relative frequency, adjacent channel should be avoided, in particular SDCCH and BCCH carrier frequency (for the general area of paragraphs 1 and 2 carrier frequency). Use of frequency hopping, the base adjacent to the take-off point, but not the same frequency-hopping algorithm. When the general frequency hopping (frequency hopping synthesizers means), the base station in the same area of frequency-hopping algorithm (HSN), but the take-off point (MAIO) can not be adjacent channel. Note: Any use of CCB does not support the way co-hopping. BSIC should also pay attention to the design, BSIC = 8 NCC + BCC, BCC can choose between 0-7 and so close to the same, the area adjacent channel BSIC should be inconsistent and should be avoided as much as possible at close range with the same frequency (especially BCCH Carrier frequency), with the BSIC. There was a higher base of the mountain, do not stop to consider as a neighbor; if there are large areas of the waters between the base station, will have to consider the station as a neighbor. Not hopping, limiting the use of the BCCH carrier frequency range, BCCH carrier frequency can be staggered as far as possible, to allocate a frequency-hopping BCCH at a certain frequency bands, so 4X3 reuse, with sufficient frequency, then, BCCH may consider even 5X3 Is the reuse 6X3 model, to reduce interference between BCCH. In large and medium-sized cities, according to the support of different devices using different frequency reuse closely, such as: MRP, 1 * 3,1 * 1, such as frequency hopping, at the same time set aside for the Department of Micro-Fen Pindian the formation of hierarchical cellular network; its Frequency reuse factor smaller. In the small and medium-sized cities, according to the support of different devices using different frequency reuse methods, the need for the formation of hierarchical network based on the actual situation to determine; its frequency reuse factor slightly larger than the large and medium-sized cities. In towns and rural areas, the frequency of rich resources, can be used in conventional 4 3 frequency reuse methods; For geographical reasons for the building of the mountain station can be independent of the frequency distribution point. O-district planning decisions for the GSM network coverage, determines the network performance indicators, the small neighborhood planning principles are as follows:Planning for the adjacent areas, under normal circumstances, in planning cell that carried out in accordance with the cellular structure of the distribution of this network set up in the adjacent areas that need attention: Macrocell in the city's residential area adjacent to configure relations, in general needs to be adjacent to the two-tier:In general, such as remote rural or suburban areas adjacent to the network configuration relations, because of this case, the distribution network is light, every cell of a wider coverage, relatively speaking, a larger distance between the two-story, so this network Adjacent to configure the relationship between the general need to consider only one cell can be In the GSM system, base stations, each assigned a color code locally known as the Base Station ID (BSIC). If a physical location, the mobile station at the same time be able to receive both the district BCCH carrier frequency, and the same number of channels they are moving to Taiwan BSIC to distinguish them. In network planning, in order to reduce the frequency interference with the generally ensure that the area adjacent BCCH carrier frequency using a different frequency, and the cellular communications system determines the characteristics of the BCCH carrier frequency reuse are bound to exist. For these same BCCH frequency of the cell containing the guarantee to their different BSIC.SCH received a mobile station, that has been synchronized to the area. However, in order to correctly translated downstream signaling channel of public information, mobile station must also know that the public signaling channel used by the training sequence code (TSC). In accordance with the GSM standard provides training sequences have a code of eight fixed format, with each number from 0 to 7, said. Each area of public signaling channel used by the TSC by the serial number of small BCC decision. Therefore, the role of the BSIC is one of the mobile station to inform the public area signaling channel used by the serial number of training. BSIC due to participate in the random access channel (RACH) of the decoding process, so it can be used to avoid mobile base stations will be sent to the area adjacent to the RACH incorrect interpretation of the district's access channel. When the mobile station in connection mode (in the process of call), it must be in accordance with BCCH on the table adjacent areas, adjacent areas of the BCCH carrier frequency of the level measured and reported to the base station. At the same time in the uplink in a survey report for each frequency, mobile station must give it to the measurement of the carrier frequency of BSIC. When in a particular environment, that is an area of the adjacent areas contain two or more of the same area of the BCCH carrier frequency, base station can rely on BSIC to distinguish between these small, so as to avoid the wrong switch, or even Failure of the switch. Mobile station in connection mode (call the process) must be measured adjacent areas of signal and results reported to the network. As the mobile station to send each of the measurements in the report includes only six of the contents of the adjacent areas, it is necessary to control mobile station and the only report of the current residential real relationship between the cell switch the situation. BSIC of the three high (that is, the NCC) for the realization of the above-mentioned purposes. Network operators can broadcast parameters "to allow the NCC" to control mobile station in the NCC report only allowed within the scope of the situation in adjacent areas. Baseband frequency hopping: the work of a number of transmitters in their respective fixed-frequency, and will bring in different-channel signal by switching to a different frequency hopping sequence on the transmitter to send to achieve frequency hopping. TRX has been tuned to each fixed frequency, which is tuned using mechanical means, slow tuner, usually RTC (Remote Tune Combiner) to complete. For each specific voice connection, is built to connect a particular time slot on the specific TRX. After coding intertwined with each belong to Burst in the slot to be connected to a dispatch sent on a different TRX. Radio Frequency Hopping (SH) do not use the RTC narrow-band coupler, instead of using the broadband hybrid coupler (Hybrid Combiner). Because each TRX issued on the frequency of each is to quickly transition of the slot. Radio frequency hopping: the launch of the transmitter frequency hopping sequence by hopping.

In the GSM, because the logic of each frame of the data is scattered intertwined in 8 of sent in TDMA frame, and the data encoded Convolutional After all, if this burst of 8 pieces of code that a small number of interference or damage, through the good Convolution of the decoder, may still be better to restore the data to send out, but if there is too much of the code block is damaged, it will be very difficult to restore the original data. Hopping through, you can make a channel will not burst for a long time in a row in a deep decline of the area (This is work in a fixed carrier frequency, low-speed static or moving the mobile station is easy to occur), the total will not be a Strong signals on the same frequency interference with such a channel codec will be able to obtain better results transmission. This is the use of frequency hopping communication technologies to improve the quality of a simple principle. GSM system uses the frequency hopping sequence is a Poisson pseudo-random variables, which can provide up to 64 kinds of frequency hopping sequence, the length of the same frame with ultra-high (3-hours, 28 minutes 53 seconds 760 ms), as far as possible in order to ensure that all Sequence between the orthogonal, frequency-hopping to ensure results. The GSM frequency hopping sequence described by two parameters: HSN (frequency hopping sequence) and MAIO (mobile allocation index offset), usually assigned to a different area of different HSN, and different MAIO value assigned to the area in A different channel. Diversity means the frequency of its anti-Rayleigh fading of capacity, due to different carrier frequency on the Rayleigh fading does not have a certain correlation (the greater the frequency difference, the smaller the correlation), so scattered in different carrier frequency of non-burst Will be subject to the same Rayleigh fading, this low-speed mobile and stationary for the mobile station is a lot of sense, is said to provide about 6.5dB of gain. The high-speed movement of MS, the same channel two successive time in the position of the burst difference has been that they do not change with the Rayleigh-related, that is almost the same time will not be affected by the decline of the impact of slow frequency hopping can provide at this time The frequency diversity gain very little. Diversity refers to the interference of its suppression of other reuse the same frequency of the cell's ability to interfere with the signal, which is provided by frequency hopping, to provide transmission path interference vary greatly improved the conditions of the worst cases of interference, so that all users access to more balanced Good communication quality, which has a large number of users of mobile communication system is very important, in particular by increasing the frequency reuse rate to increase communications capacity is crucial. Usually interfere with the provision of diversity effect, the number of points should not jump frequently less than 3. Diversity means the frequency of its anti-Rayleigh fading of capacity, due to different carrier frequency on the Rayleigh fading does not have a certain correlation (the greater the frequency difference, the smaller the correlation), so scattered in different carrier frequency of non-burst Will be subject to the same Rayleigh fading, this low-speed mobile and stationary for the mobile station is a lot of sense, is said to provide about 6.5dB of gain. The high-speed movement of MS, the same channel two successive time in the position of the burst difference has been that they do not change with the Rayleigh-related, that is almost the same time will not be affected by the decline of the impact of slow frequency hopping can provide at this time The frequency diversity gain very little. Diversity refers to the interference of its suppression of other reuse the same frequency of the cell's ability to interfere with the signal, which is provided by frequency hopping, to provide transmission path interference vary greatly improved the conditions of the worst cases of interference, so that all users access to more balanced Good communication quality, which has a large number of users of mobile communication system is very important, in particular by increasing the frequency reuse rate to increase communications capacity is crucial. Usually interfere with the provision of diversity effect, the number of points should not jump frequently less than 3.