Background technology
Along with the development of wireless communication technology to multi-service, broadband direction, third generation partner program (3GPP, 3
rdGeneration Partnership Project) started Long Term Evolution (LTE, Long Term Evolution) project.
The purpose of the various WiMAX access technologies of 3GPP development is that the experience of omnibearing mobile multimedia service will be provided for the client.But under a lot of conditions, this purpose is also unrealized, especially in the outlying district or resident's accumulation regions, can't realize because these regional signals badly cause this purpose of 3GPP.
A feasible solution, be to dispose to need not the base station from home that macro base station (macro eNB) can provide maximum Mobile data speed in home-ranges, be called as " Pico cell " base station (femto eNB) according to these base station from home of its power.
According to base station transmitting power, dissimilar base station can be divided into following kind:
(1)+45dBm: the about macro base station of 5km outside can covering chamber;
(2)+30dBm: the microcell base station that can cover about 0.5km;
(3)+15dBm: the femto base station of about 50 meters scopes in can covering chamber.
Base station from home is connected with whole network by public switch telephone network, and this can utilize the digital subscriber line (DSL, Digital Subscriber Line) of registering one's residence to realize usually.Kinsfolk's mobile phone is the femto base station communication in consanguinity only, thereby user and the macro base station of this family can be disconnected fully.
For above-mentioned various types of cellular cells, system need to distribute Physical Cell Identifier PCI for them, to distinguish different districts.And different PCI is adopted in adjacent residential quarter, can realize the presence of intercell interference randomization.PCI can realize the exclusive scrambling in residential quarter, namely after chnnel coding, to the random scrambling of interference signal.By different scramblers, the information of different districts is distinguished, allowed subscriber equipment (UE, UserEquipment) only decode for useful information, disturb thereby reduce.
Therefore, in order to distinguish different residential quarters, and reduce presence of intercell interference, need to propose the distribution method of PCI.The distribution of PCI in network, must be under the different prerequisite in the PCI space that guarantees that macrocellular and Pico cell use, can make the probability of the conflict of PCI between Pico cell lower, and the enough distance far away of the multiplexing maintenance of PCI that can make macrocellular (microcellulor is included in macrocellular).
In LTE R8, the value range of agreement regulation PCI is 1-504, namely always has 504 PCI for distributing.If consider merely the covering of macro base station, so existing 504 PCI enough use.But if consider many femto base station in residential building, 504 PCI may not be enough.And, still do not provide the method for specifically how to divide and to distribute PCI in present technology.
Summary of the invention
Technical problem to be solved by this invention is to provide the distribution method of Physical Cell Identifier in a kind of long-term evolving network, guarantee under the different prerequisite in macrocellular and Pico cell use PCI space, the multiplexing maintenance of PCI that can make macrocellular (microcellulor is included in macrocellular) is distance far away enough.
In order to solve the problems of the technologies described above, the invention provides the distribution method of Physical Cell Identifier PCI in a kind of long-term evolving network, comprising:
First mark off two continuous PCI spaces separately in the PCI scope, wherein: a distribution that is used for femto base station residential quarter PCI; Another piece is used for the distribution of macro base station residential quarter PCI, and it is enough large to distribute to the PCI space of macro base station residential quarter, so that the PCI multiplex distance of macro base station residential quarter is enough far away; The number of rings that the PCI multiplex distance enough far refers to form enough macrocellulars of macro base station bunch multiply by cell diameter, and the PCI space refers to greatly that enough the PCI number that distributes equals the residential quarter sum of enough macrocellular bunch at least.
Further, for the low sparse type covering scene of building density, the distribution that continuous PCI space is used for femto base station residential quarter PCI refers to:
This continuous PCI space is total, and (50 ± m) individual PCI numerical value are used for distributing to the femto base station residential quarter; Wherein m=0~20, adjust according to building density.
Further, and the density of using femto base station high for building density is high intensive covering scene also, and the distribution that continuous PCI space is used for femto base station residential quarter PCI refers to:
The individual PCI numerical value in this continuous PCI space total [(50 ± m) * 2] is used for distributing to described femto base station residential quarter; Wherein said m=0~20 are adjusted according to building density.
Further, another piece continuous PCI space is used for the distribution of macro base station residential quarter PCI, and it is enough large to distribute to the described PCI space of macro base station residential quarter, so that the PCI multiplex distance of macro base station residential quarter is enough far away, refers to:
The PCI number that distributes equals the residential quarter sum in macrocellular bunch 10 rings at least.
Further, also comprise:
Mark off again a continuous PCI space in the PCI scope, be used for keeping for macro base station as macrocellular dilatation use, perhaps be used for keeping for femto base station to use as the Pico cell dilatation.
Further, also comprise:
The PCI space that last piece in the PCI scope is continuous is used for keeping for femto base station to use as the Pico cell dilatation under the prerequisite of keeping for macro base station PCI space; Perhaps be used for keeping for macro base station to use as the macrocellular dilatation under the prerequisite of keeping for femto base station PCI space; And the PCI number sum in all continuous PCI space of division equals the total number of PCI in the PCI scope.
Adopt the distribution method of PCI in LTE network of the present invention, guarantee under the different prerequisite in macrocellular and Pico cell use PCI space, the multiplexing maintenance of PCI that can make macrocellular is distance far away enough, and can make the probability of PCI conflict between Pico cell lower, can also reserve resource for the network capacity extension.
Embodiment
The distribution method of Physical Cell Identifier in long-term evolving network provided by the invention, its inventive concept is, PCI scope (1~504) is divided into three continuous spaces, wherein: two distribution and reservations that are respectively used to femto base station, distribution and a reservation that is used for macro base station, and the PCI space of distributing to macro base station is enough large, so that the PCI multiplex distance of macro base station is enough far away.
Below in conjunction with accompanying drawing and preferred embodiment, technical scheme of the present invention is at length set forth.Following examples only are used for description and interpretation the present invention, and do not consist of the restriction to technical solution of the present invention.
As shown in Figure 1, the honeycomb of a macro base station bunch innermost ring is 1 residential quarter, and second ring is 6 residential quarters ..., n ring is 6 * (n-1) individual residential quarters (n=4 in figure).
So, the residential quarter sum of n ring is: (3 * 2) * [1/2 * n * (n-1)]+1=3 * n * (n-1)+1;
When n=10, the residential quarter sum of 10 rings is: 3 * 10 * (10-1)+1=271.
As shown in Figure 2, femto base station is the base station of using in subscriber household, is linked into network by DSL.Because metope stops, so cell coverage area is very little, only has the conflict that just has PCI between neighbor cell.
The distribution method embodiment of Physical Cell Identifier in long-term evolving network provided by the invention comprises the following steps as shown in Figure 3:
310: first mark off two continuous PCI spaces separately in the PCI scope, wherein, a distribution that is used for femto base station residential quarter PCI; Another piece is used for the distribution of macro base station residential quarter PCI, and it is enough large to distribute to the PCI space of macro base station residential quarter, so that the PCI multiplex distance of macro base station residential quarter is enough far away;
320: mark off two continuous PCI spaces in the PCI scope, one is used for keeping for macro base station as dilatation use again, and another piece is used for keeping for femto base station to use as dilatation; And the described PCI number sum in all described continuous PCI space of division equals the total number of described PCI in described PCI scope, process ends.
Embodiment one
For general urban district covering scene, certain building is arranged namely but density is not high especially, the distribution method in PCI space is as follows:
The first step: be a continuous PCI space of femto base station cell allocation, scope is 1~50, and 50 PCI numerical value are wherein arranged;
Can satisfy like this very low requirement of collision probability of PCI in picocell coverage area, and then can optimize the indexs such as cutting off rate of conversing such as travelling carriage in network.
Second step: for macrocellular bunch base station cell distributes an enough large continuous PCI space, scope is 51~321, and wherein the PCI number is 271;
Take 500 meters of city radius of societies as representative value, 2000 meters of suburb radius of societies are representative value, and establish n=10.After taking so this step, be about 10 * 500 * 2=10000 rice at the PCI in city typical case multiplex distance, and the PCI in suburb typical case multiplex distance is about 2000 * 10 * 2=40000 rice.As seen, can guarantee that like this multiplex distance of PCI of macrocellular is enough far away.
The 3rd step: be macrocellular bunch continuous PCI space of reservation, base station, scope is 322~447, and wherein the PCI number is 126, is used for the macro base station dilatation and adds honeycomb;
The 4th step: reserve a continuous PCI space for femto base station, scope is 448~504, and wherein the PCI number is 57.
The quantity of considering following femto base station can be very large, therefore reserves this block space for it, can further optimize These parameters when needed.Reservation PCI space can further reduce the probability of PCI conflict between Pico cell.
Embodiment two
For suburb and rural area covering scene, namely building density is low, and the distribution method in PCI space is as follows:
The first step: for femto base station distributes a continuous PCI space, scope is 1~30, and 30 PCI numerical value are wherein arranged;
Certainly, by embodiment one, two, for general city or suburb, rural area covering scene, the PCI numerical value of distributing to femto base station is (all be fine in 50 ± m) scope, wherein m=0~20, adjust according to concrete building closeness.
Second step: be the enough large continuous PCI space of macrocellular bunch base station assigns, scope is 31~301, and wherein the PCI number is 271;
The multiplex distance of PCI that can guarantee like this macrocellular is enough far away.
The 3rd step: be macrocellular bunch continuous PCI space of reservation, base station, scope is 302~447, and PCI number wherein is 146, can be used for dilatation and adds macrocellular;
The 4th step: reserve the PCI space for Pico cell, scope is 448~504, and PCI number wherein is 57.
Reserve the probability that PCI can further reduce PCI conflict between Pico cell.
Embodiment three
For the dense city scene, i.e. also higher zone of the higher and density of using femto base station of building density, the distribution method in PCI space is as follows:
The first step: for Pico cell distributes a continuous PCI space, scope is 1~100, and 100 numerical value are wherein arranged;
Certainly, for building high density covering scene, PCI numerical value all is fine in the scope of [(50 ± m) * 2], and wherein m=0~20, adjust according to the closeness of concrete building.
Second step: be the enough large continuous PCI space of one of macrocellular bunch base station assigns, such as scope is 101~371, PCI number wherein is 271;
The 3rd step: be macrocellular bunch continuous PCI space of reservation, base station, scope is 372~447, and PCI number wherein is 76, is used for dilatation and adds macrocellular;
Consider at dense city, the density of macro base station is higher, unlikely carries out dilatation on a large scale, so the dilatation demand still can be satisfied in the PCI space that step is macrocellular bunch reservation.
The 4th step: reserve a continuous PCI space for femto base station, scope is 448~504, and PCI number wherein is 57.
Reservation PCI space can further reduce the probability of PCI conflict between Pico cell.