Title of Invention

METHOD FOR PILOT OFFSET NUMBER MULTIPLEX PLANNING IN CDMA NETWORK

Abstract

The present invention relates to a method for planning pilot offset number multiplex in CDMA network, at least includes the following steps: determining the cover radiuses of the smallest subzones in dense area and/or non-dense area according to network scale and requirement of expanding capacity; determining a pilot increment value and the pilot difference between many subzones of one station, and then dividing the available pilots into some pilot groups; counting the pilot offset number multiplex distance according to the cover radius of the smallest subzone and the pilot increment value; setting the grids and the grid line yardstick of said pilot offset number multiplex areas, and then distributing each grid orderly to said pilot groups, thereby implementing the pilot offset number multiplex between the areas. The present invention is clear on the steps and has widely applicability, it can efficiently and conveniently design the pilot for oversize network in one time, and it has thought over the question of expanding capacity for the future at design days. As a result, it doesn"t need to redesign the used pilot for expanding capacity in future, and it couldn"t take impact to the existing networks.

Full Text

Method for Pilot Offset Number Multiplex Planning in CDMA Network Field of the Invention The present invention relates to a method for planning pilot offset number multiplex in CDMA network, and particularly, to a method for planning pilot offset number multiplex at the plan stage of CDMA cellular mobile communication network to realize the ordered distribution of pilots, and belongs to the field of communication technology. Background Art With the vigorous development of mobile communication technology, users have higher and higher requirement on the quality of network, and how to improve the communication quality of wireless network becomes an important topic during network construction. Network construction relates to many stages such as network plan, engineering construction and network optimization, wherein the network plan stage decides the architecture of the whole network, and plays a decisive role in whether the network completed can satisfy the requirements on coverage and capacity. In the network plan stage, an 2 important work in wireless parameter plan is pilot offset number multiplex plan, or short for PN (Pseudo random Number) multiplex plan, and improper PN multiplex plan will result in serious consequence, and render lowered quality of the network. The complexity of PN multiplex plan increases dramatically with the increase of network scale, and the construction of wireless network will certainly be conducted by batch due to the factors that potential network scale is difficult to be forecast and investment budget is limited, and if there is still no perspective method for planning PN multiplex, it is certain that PN should be re-designed for each construction, which is time-consuming and effort-consuming, and may cause great impact on current network. Currently there are only a few instructive norms regarding multiplex distance restriction, pilot increment (pilot_INC) selection, and the like, and there is no common practice as to how to plan PN multiplex of a network, especially that of an oversize network. There are mainly two patents at present as follows: The idea of the American patent No. 6618432, invented by Ganesh and the like, entitled "System and Method for Minimizing Interference and Optimizing PN Planning in CDMA Networks", is as follows: planning PN is realized in simulating way, and first, PN is dispensed to each subzone, the performance of the system is simulated according to 3 the dispensed PN, and the small regions which performance is inferior is marked, then PN of the small regions is adjusted, and the performance of the system is simulated again till performance requirement is satisfied. The idea of the American patent No. 6490313, invented by Ganesh and the like, entitled "System and Method for PN Offset Index Planning in A Digital CDMA Cellular Network", is as follows: planning PN is realized in simulating way, and first, PN is dispensed to each small region, the interference among the small regions is obtained by tool simulating, a reasonable threshold is set for the interference, and if the threshold is exceeded, adjust PN of relevant base stations till requirements are satisfied. Main ideas of the existing patents lie in using simulating tools. On the basis that preliminary PN plan is completed, looking for probably existed problems utilizing simulating tools, then such problems are solved by adjusting PN for regions with problems. Defects that doing so mainly lie in the followings: 1, there are many artificial factors for preliminary PN planning, preliminary plan results obtained by different planners are different and the complexity of follow-up adjustment is also different. 2, each preliminary plan will bring different final adjustment results, which actually do not help to engineering application and filing. 3, influences conducted by adding base stations are not or hardly 4 considered. In fact, since the whole relevance of algorithm is adjusted, adding new stations will cause re-dispensing PN for the whole network or most of the base stations of the network; while the cost for re-planning the whole network is very high, and whole adjusting means change of a large batch of parameters such as the configurations of adjacent areas and modifications of engineering file. 4, simulating tools are used to calculate interference and guide adjustment, which is not allowed in part of actual projects, and a simpler operative method for planning PN, which can ensure multiplex distance, is desired. In addition, in a Chinese application entitled "A Method for Planning PN in CDMA Cellular System", the artificial operations are staged, and a one-to-one mapping mode is used for the stations in groups of dense area and non-dense area, which to a certain extent ensures that the multiplex distance can not be so close by PN grouping, however, since this mapping relation is on the basis of base stations, the application cannot provide general mapping rules, and PN multiplex distance should be ensured by the planner artificially, said method per se cannot forecast theoretical minimum multiplex distance. Further, said method ensures addition of stations in a way of reserving PN, while, it is still subject to answer that how many PN should be reserved to meet the requirement of adding stations and meanwhile the cover range of the multiplex group is not so 5 small. Summary of the Invention Aiming at potential unstable factors in the running of wireless network and the technical problem of plan bottleneck in subsequent capacity expanding construction of the network which are brought forth by the disordering of PN multiplex plan in current CDMA network plan, the present invention provides a method for planning pilot offset number multiplex in CDMA network, which can efficiently plan pilots and meet the demand of smoothly expanding capacity. In order to achieve the above objects, the technical solution which the present invention adopts is a method for planning pilot offset number multiplex in CDMA network, and it at least comprises the following steps: Step 1: determining the cover radiuses of the smallest subzones in dense area and non-dense area according to network scale and the requirements of capacity expanding; Step 2: determining the value of pilot increments and the pilot differences between many subzones of one station, and then dividing the available pilots into some pilot groups; Step 3: counting the distance of the pilot offset number multiplex 6 according to the cover radius of the smallest subzone and the value of the pilot increments; and Step 4: setting the grids and the grid line yardstick of the said pilot offset number multiplex areas, and then distributing each grid orderly to the said pilot groups, thereby implementing the pilot offset number multiplex between the areas. On the basis of the above-described technical solution, it can further comprise the following steps: Step 5: further amplifying the pilot offset number multiplex distance of base stations in non-dense area of the whole network; and Step 6: checking the planning results of the whole network, and eliminating the results whose pilot offset number multiplex distance is shorter. In the above step 1, the cover radius of the smallest subzone can be determined by analyzing potential network scale and capacity expanding demand and making comparison between network scales of the same or close frequency bands. Upon the pilot interval between two sectors at the base station apparatus is pilot increment and the directions of main lobes are opposite, then the value of the pilot increment in said step 2 can be calculated based on mutual interference according to the reverse demodulation capability of the base station. 7 In said step 4, the grid line yardstick is double length of the cover radius of the smallest subzone, pilot offset number multiplex areas are squares, the side length of the square is pilot offset number multiplex distance, and grids in the multiplex area are orderly numbered, and then the pilot groups are orderly assigned to the grids in multiplex areas. If a special circumstance that there are two base stations in one grid appears, then borrow pilots according to the special circumstance and carry out the following steps: For the base stations located on the borderlines of the grids, the ones located on horizontal line belong to the upper grid, and the ones located on vertical line belong to the right grid. If pilot groups of a sub-grid are not enough, it can take priority to use the remaining pilot groups after distributing once, and if the remaining pilot groups are used up, it can take priority to borrow pilot groups from the sub-grids around, the borrowing starts from the right till the eighth neighbor sub-grid in clockwise order or anticlockwise order. If the number of the grids is more than that of the pilot groups, assign starts from the beginning till all are assigned. If the number of the pilot groups is multiple to that of the grids, multiple pilots are assigned to each grid. If there are remaining pilot groups after assigning once, they can be kept for later use and lent to the grids with more base stations assigned 8 this time, or can be kept for expanding capacity in the future. Compared with the prior art, the main technical features of the present invention lie in: 1. Changing disordered distribution into orderly filling, and the method is standard and efficient; 2. being able to forecast the smallest PN multiplex distance which is restricted by PN resources; 3. adopting geographic blank filling way, which can ensure that the smallest PN multiplex distance will not be shortened remarkably due to artificial factors and the addition of a few base stations; and 4. ensuring in a long time that PN plan for adding base stations has been predetermined and PN will not be re-planned due to the addition of the base stations. The present invention is clear on the steps and has widely applicability, it can efficiently and conveniently design the pilots for oversize network in one time, and it has thought over the question of increasing capacity in the future at initial days of construction. As a result, it doesn't need to re-design the used pilots for increasing capacity in the future, and it would not take impact to the existing networks. Brief Description of the Drawings 9 Figure 1 is a flow view of orderly distributing PN multiplex in CDMA wireless networks of the present invention; and Figure 2 is a schematic view of a specific embodiment of the PN multiplex processing flow of the present invention. Embodiments for Carrying Out the Present Invention The present invention will be further described with the drawings hereinafter. In the method for planning pilot offset number multiplex in CDMA network raised by the present invention, under the precondition of reasonably designing the smallest cover radius of subzone and the pilot increment (Pilot_ INC), dispenses each grid to the pilot groups orderly by designing the grid yardsticks of pilot offset number multiplex areas, and then conducts pilot offset number multiplex between the areas. The present invention can be used in initial pilot plan of CDMA wireless network, and it can also be used in pilot plan of network capacity expanding construction at later days, and has features of smoothly expanding capacity and smallest impact to the existing networks. Figure 1 is a flow view of the method of the present invention. The following is the description of the key procedures for carrying out 10 the method. 1. Analyzing the potential network scale and capacity expanding demands, and then determining the cover radius of the smallest subzone in dense city, general city, suburb and countryside. Comparison can be adopted to analyze the potential network scale, and reference is made to the network scales in the same or close frequency bands of the present service provider or competitors. 2. Suppose that the pilot interval of the two sectors of the base station is pilot increment (PilotINC) and the directions of the main lobes are opposite, the cover radiuses of the subzones in dense and non-dense city can be calculated based on interference according to the reverse demodulation capacity of base station, and then the pilot increment (Pilot_INC) value of the present network can be determined by combining the actual complexity of the network. In addition, the pilot difference between several subzones of one station should be determined, and then all available pilots are divided into some pilot groups (PN groups) by combining the determined pilot increment (Pilot_INC) value. 3. Generally, the PN multiplex distance is the longer, the better, but theoretic deduction shows that the multiplex distance of the pilot groups is generally restricted by the pilot increment (Pilot_INC) value. First, in case that base stations are distributed evenly: suppose radius of the subzone is r, the coverage shape is a standard regular hexagon wireless 11 beehive, then the coverage area of a station is 6x 1/2 x sin(60) x r2= 2.6x r2, the coverage area of a base station in the perfect multiplex area including n x n subzones is closely as: 2.6r2 x n2, and the side length of the square multiplex block covered by the base station group is (2.6r2 x n2)1/2 =1.61 n x r, and suppose the multiplex distance is k x r, then 1.61n x r = k x r,k = 1.61n, that is: n = 0.62k . The total number of the base stations is: n x n = (0.62k)2 = 0.3844k2. There are 512 PN code recourses in total, and suppose a base station has 3 sectors, then, the number of the available pilot groups is 512/pilot_lNC/3 according to the determined pilot increment (Pilot_INC). In order to match the number of the base stations and the available pilot groups, the equation is as follows: 0.3844k2 = 512/pilot_INC/3,k = (443.98196/pilot_INC)1/2 . 4. The smallest cover radius of the subzone in the plan is obtained and double length of the radius is served as the yardstick of the grid line. A pilot offset number multiplex area is a square, and its side length is the pilot offset number multiplex distance, that is, k x k, then there are totally k2 /4 grids, and the grids of the said area are numbered orderly. 5. The pilot groups are orderly assigned to the sub-grids in the multiplex areas. If there are two base stations in one grid, pilots are borrowed according to certain principles, and the brief description of the principles is as follows. 12 (1) Adscription of the base stations located on the borderlines of the grids: the ones located on the horizontal line belong to the upper grid, and the ones located on the vertical line belong to the right grid. (2) Lack of pilot groups in a sub-grid: it can take priority to use the remaining pilot groups after dispensing once, and if the remaining pilot groups are used up, it can take the priority to borrow pilot groups from the sub-grids around. In order to uniquely borrow, the borrowing starts from right till the 8th grid in clockwise or anticlockwise order. (3) If the number of the grids is more than that of pilot groups, then assignment is conducted from the beginning until all are assigned. (4) If the number of the pilot groups are multiple to that of the grids, then a plurality of pilots are assigned to each grid. (5) If there are remaining pilot groups after assigning, they can be kept for later use or lent to the grids with more stations assigned this time, or can be reserved for capacity expanding adjustment in the future. 6. According to different areas and landforms in the whole network, the PN plan thereon is adjusted, and for some villages and the countryside, the pilot offset number multiplex distance can be further magnified. 13 7. Results of the whole network plan are checked with the help of a computer or hand, the result that the pilot offset number multiplex distance is shorter can be eliminated, and then it can be ensured that the whole network is qualified. 8. Relevant output documents of the final pilot plan are filed for the sake of recheck and capacity expanding plan in the future. The procedure for realizing the present invention is described hereafter with the pilot plan of a certain CDMA network at the initial days of construction. The network locates at the combined part of city and suburb, there are nearly 200 base stations, and processes of the embodiment are as shown in Figure 2, the total study takes 800 hours in all. Main processing phases are follows. 1. Network scale analysis: 186 base stations are planned for the city, in view of the service provider's 1800GSM system (nearly 700 base stations), since there exists the potential demand of adding base stations in the future, general consideration should be taken for PN plan, it should not only satisfy the demands of the present network, but also make enough room for future capacity expanding, then PN of the whole network need not be re-planned in the case of adding base stations or expanding capacity in the future, or it will be very difficult for subsequent plan. 14 2. Selection of PILOT _INC and determination of PN groups: in view of factors such as the density of future base stations, PILOT_INC is 3, each base station has 3 sectors, all available pilots can be used up once, they can be dispensed to 512/3/3=56 base stations, and the PN of each base station are referred to as a PN group, and even there are double sectors and omnidirectional base stations, only one PN group is dispensed. A mode that the increment existing among the sectors is 168 is adopted to set up PN. 3. Determination of PN multiplex distance: the cover radius of the smallest subzone analyzed according to the contrast will reach to 0.5 km, so the multiplex distance is 6 km. In order to ensure the multiplex distance of 6 km, l km is added and a multiplex block by 7 km x 7km is selected. 4. Determination of the size of sub-grid and the ordering of the same: the multiplex block is divided into 49 sub-grids by lkm x lkm, and they are assigned spirally with the 1st to the 49th from the top right corner. 5. Assignment of the grid PN groups: the 1st to 49th PN groups are orderly assigned to sub-grids, and the surplus is kept for later use. 6. Adjustment of the whole network: according to the actual landforms, the multiplex distance of suburbia and countryside in which the density of the base stations is smaller, the west, to which east and south of the city belong, can be increased to increase the cover radius of 15 every base station. 7. Check of the whole network: the multiplex distance is checked by manually checking on an electronic map and by using optimization tools, and the smallest multiplex distance of the present plan is 7.1km. 8. Filing of the plan documents: a document such as PN Plan Template Diagram Layer of Some City (mapinfo diagram layer) can be made, and the document can serve as the main source for checking and adding base stations in the future, meanwhile the document is convenient for filing; and the contents about PN Plan List of Some City in the document will be added to the information list of the base stations for use when the base stations start to operate. While the present invention has been particularly shown and described with reference to the embodiments thereof, it will be understood by those skilled in the art that any amendment or equivalent replacement made to the technical solution of the present invention without departing from the spirit and scope of the present invention shall all be covered by the scope of the claims of the present invention. 16 What is claimed is: 1. A method for planning pilot offset number multiplex in CDMA network at least comprising: step 1: determining the cover radiuses of the smallest subzones in dense area and non-dense area according to network scale and capacity expanding requirement; step 2: determining a pilot increment value and the difference between the pilots of .subzones of one station, and then dividing available pilots into some pilot groups; step 3: counting pilot offset number multiplex distance according to the cover radius of the smallest subzone and the pilot increment value; and step 4: setting the grids and the grid line yardstick of a pilot offset number multiplex area, and then distributing the grids to the said pilot groups orderly, thereby implementing the pilot offset number multiplex between the areas, 2. The method for planning pilot offset number multiplex in CDMA network according to claim 1, characterized in comprising the following steps after step 4: step 5: further amplifying the pilot offset number multiplex distance of 17 the base stations in non-dense area of the whole network; and step 6: checking the plan results of the whole network, and eliminating the results that the pilot offset number multiplex distance is shorter. 3. The method for planning pilot offset number multiplex in CDMA network according to claim 1 or 2, characterized in that the specific procedure of step 1 comprises analyzing potential network scale and capacity expanding demand; making comparison between network scales of the same or close frequency bands; and determining the coverage radius of the smallest subzone. 4. The method for planning pilot offset number multiplex in CDMA network according to claim 1 or 2, characterized in that procedure for obtaining the pilot increment value in said step 2 comprises: considering the pilot interval of two sectors of the base station is the pilot increment and the directions of main lobes are opposite, then counting the coverage radiuses of the subzones in dense area and non-dense area based on mutual interference according to the reverse demodulation capability of the base station; then obtaining the pilot increment value in combination with the real complexity of the network. 18 5. The method for planning pilot offset number multiplex in CDMA network according to claim 1 or 2, characterized in that the step 4 is specifically as follows: first, double length of the cover radius of the smallest subzone being served as the grid line yardstick; then, numbering the grids in the pilot offset number multiplex area orderly; the pilot offset number multiplex area is a square, and its side length is the pilot offset number multiplex distance; and finally, assigning the pilot groups to all grids in the pilot offset number multiplex area. 6. The method for planning pilot offset number multiplex in CDMA network according to claim 5, characterized in that in the procedure of assigning the pilot groups orderly, if two base stations exist in one grid, the step of borrowing pilots shall be executed based on the following: for base stations located on the borderlines of the grids, the ones located on the horizontal line belonging to the upper grid, and the ones located on the vertical line belonging to the right grid. 7. The method for planning pilot offset number multiplex in CDMA network according to claim 5, characterized in that during assigning the pilot groups orderly, if there are two base stations in one grid and 19 there are not enough pilot groups in a certain grid, the step of borrowing pilots shall be executed, and the procedure of borrowing pilots comprises using the remaining pilot groups by priority after distributing once, and if the remaining pilot groups are used up, it can borrow from the sub-grids around by priority, the borrowing starts from the right till the eighth neighbor sub-grid in clockwise or anticlockwise order. 8. The method for planning pilot offset number multiplex in CDMA network according to claim 5, characterized in that during assigning the pilot groups orderly, if there are two base stations in one grid and the number of the grids is more than that of the pilot groups, the step of borrowing pilots shall be executed, and the procedure of borrowing pilots is to assign from the beginning till all are assigned. 9. The method for planning pilot offset number multiplex in CDMA network according to claim 5, characterized in that during ssigning the pilot groups orderly, if there are two base stations in one grid and the number of the pilot groups is multiple to that of the grids, the step of borrowing pilots shall be executed, and the procedure of borrowing pilots is to assign a plurality of pilots to each grid. 20 10.The method for planning pilot offset number multiplex in CDMA network according to claim 5, characterized in that during assigning the pilot groups orderly, if there are two base stations in one grid, the step of borrowing pilots shall be executed, and if there are remaining pilot groups after assigning once, they can be kept for later use and lent to grids with more base stations assigned this time, or can be kept for expanding capacity in the future. 21 The present invention relates to a method for planning pilot offset number multiplex in CDMA network, at least includes the following steps: determining the cover radiuses of the smallest subzones in dense area and/or non-dense area according to network scale and requirement of expanding capacity; determining a pilot increment value and the pilot difference between many subzones of one station, and then dividing the available pilots into some pilot groups; counting the pilot offset number multiplex distance according to the cover radius of the smallest subzone and the pilot increment value; setting the grids and the grid line yardstick of said pilot offset number multiplex areas, and then distributing each grid orderly to said pilot groups, thereby implementing the pilot offset number multiplex between the areas. The present invention is clear on the steps and has widely applicability, it can efficiently and conveniently design the pilot for oversize network in one time, and it has thought over the question of expanding capacity for the future at design days. As a result, it doesn"t need to redesign the used pilot for expanding capacity in future, and it couldn"t take impact to the existing networks.

Documents:

00407-kolnp-2007 abstract.pdf

00407-kolnp-2007 claims.pdf

00407-kolnp-2007 correspondence-1.1.pdf

00407-kolnp-2007 international publication.pdf

00407-kolnp-2007 priority document.pdf

0407-kolnp-2007-correspondence others.pdf

0407-kolnp-2007-description (complete).pdf

0407-kolnp-2007-form1.pdf

0407-kolnp-2007-form3.pdf

0407-kolnp-2007-form5.pdf

0407-kolnp-2007-international search authority report.pdf

407-KOLNP-2007-(13-03-2014)-CORRESPONDENCE.pdf

407-KOLNP-2007-(16-12-2014)-CLAIMS.pdf

407-KOLNP-2007-(16-12-2014)-CORRESPONDENCE.pdf

407-KOLNP-2007-(16-12-2014)-OTHERS.pdf

407-KOLNP-2007-(26-06-2014)-CORRESPONDENCE.pdf

407-KOLNP-2007-(27-06-2014)-CORRESPONDENCE.pdf

407-KOLNP-2007-(29-10-2013)-ABSTRACT.pdf

407-KOLNP-2007-(29-10-2013)-CLAIMS.pdf

407-KOLNP-2007-(29-10-2013)-CORRESPONDENCE.pdf

407-KOLNP-2007-(29-10-2013)-DESCRIPTION (COMPLETE).pdf

407-KOLNP-2007-(29-10-2013)-DRAWINGS.pdf

407-KOLNP-2007-(29-10-2013)-EXAMINATION REPORT REPLY RECEIVED.pdf

407-KOLNP-2007-(29-10-2013)-FORM-1.pdf

407-KOLNP-2007-(29-10-2013)-FORM-2.pdf

407-KOLNP-2007-(29-10-2013)-FORM-3.pdf

407-KOLNP-2007-(29-10-2013)-FORM-5.pdf

407-KOLNP-2007-(29-10-2013)-OTHERS.pdf

407-KOLNP-2007-(29-10-2013)-PA.pdf

407-KOLNP-2007-(30-05-2014)-CLAIMS.pdf

407-KOLNP-2007-(30-05-2014)-CORRESPONDENCE.pdf

407-KOLNP-2007-(30-05-2014)-OTHERS.pdf

407-kolnp-2007-form 18.pdf

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