[0052] The present invention will be further explained below in conjunction with the drawings.
[0053] figure 1 This is the flow chart of the present invention. The present invention mainly includes the following parts:
[0054] 1) Contract design. In the considered heterogeneous network, the base station calculates the uplink and downlink node interference and user types based on the initialized network data, and specifically proposes the optimization problem of the contract, and finds the optimal under the constraints of individual rationality and incentive compatibility Resource pricing.
[0055] 2) Contract broadcasting. The base station arranges the users in ascending order according to the user type information it has. At the same time, arrange the designed contracts in ascending order of resource prices, and then broadcast them.
[0056] 3) Sign the contract. After the user receives the contract, according to the resource block price and its own benefit function, calculate whether the benefit value is the maximum value that the user type can obtain, if it is, then sign the contract and send a feedback signal to the base station, and the base station receives the feedback After the signal, the resource block is leased to the user; otherwise, the user refuses to sign and waits for the next round of the base station design contract to broadcast the contract.
[0057] The following is a detailed description of the above steps:
[0058] 1) Analyze the interference of base stations and users in the same cell in uplink and downlink;
[0059] reference figure 2 As shown in the architecture diagram, assuming that the base station set in the cell in the heterogeneous network is L={1,2,...L}, and the user set is K={1,2,...K}, decoupling means that users are in uplink and downlink Different base stations can be connected. Assume that user k is connected to base station u in uplink, and user k is connected to base station v in downlink. Then the interference received by base station 1 in uplink is:
[0060]
[0061] among them, Represents interference from other downlink base stations, Represents interference from other uplink users, and the calculation formula is:
[0062]
[0063]
[0064] b represents access bandwidth, p represents transmission power, τ represents a certain time slot, Represents the binary variable of the service provided by the base station u'to the user k'in the time slot τ, Represents the access binary variable of user k'accessing base station u'in time slot τ, g u′u Represents the link gain between base station u and base station u;
[0065] The interference received by user k in downlink is:
[0066]
[0067] among them, Indicates the interference from other downlink base stations received by user k, Indicates that user k receives interference from other uplink users,
[0068]
[0069]
[0070] among them, Represents the binary variable of the service provided by the base station v'to the user k'in the time slot τ, Represents the access binary variable of user k'accessing base station v'in time slot τ, g v′k Represents the link gain between user k and base station v';
[0071] 2) Define user types, and reproduce node benefits and social surplus functions;
[0072] For a given user k to access a base station l, the value created by the leased resource can be given by the Shannon-Hartley theorem, which describes the data transmission rate, namely:
[0073] Φ kl =B kl log 2 (1+SINR kl )
[0074] Among them, Φ kl Indicates the maximum information transfer rate provided by base station l to user k, B kl Indicates the channel bandwidth between base station l and user k.
[0075] SINR kl Represents the signal-to-noise ratio. In the downlink of decoupled single access, we can express it as:
[0076]
[0077] σ 2 It stands for Gaussian White Noise (AWGN). Through the definition of SINR, we can define the user type according to the different characteristics of the interference suffered by each user, including the classification of uplink and downlink. Since the base station is interfered when the user accesses the base station in the uplink, considering the single access, the base station type can represent the user type. As the receiver, the downlink user can directly analyze the definition type of interference received, namely:
[0078]
[0079] Next, we define the node benefit and social surplus function. For the base station, its benefit function can be expressed as:
[0080] U(b,p)=π(b,p)-F(b,p)
[0081] The benefit function is also the objective function of the optimization problem in the contract. U(b, p) represents the benefit value of the base station, b represents the access bandwidth, p represents the transmission power, and π(b, p) represents the resource leased by the base station to the user. Price, F(b,p) represents the cost of the base station, including the cost of leasing the resources obtained by the base station from the operator plus the maintenance cost, that is, the degradation of data transmission service performance caused by interference, which can be expressed as:
[0082] F(b,p)=F 0 +T(b, p)
[0083] F 0 Indicates the cost of leasing resources obtained by the base station from the operator, and T(b, p) represents the maintenance cost related to bandwidth and power;
[0084] For users, the benefit function is:
[0085] V(θ,b,p)=R(θ,b,p)-π(b,p)
[0086] Among them, V(θ, b, p) represents the benefit value of the user, and R(θ, b, p) represents the data rate when the user accesses the base station.
[0087] For social surplus, its function can be expressed by the sum of base station benefit and user benefit function. The result is:
[0088] S(θ,b,p)=U(b,p)+V(θ,b,p)=R(θ,b,p)-F(b,p)
[0089] 3) Contract design, giving constraints such as individual rationality and incentive compatibility;
[0090] When designing the contract optimization problem, two constraints are included, namely individual rationality and incentive compatibility, both of which ensure that the solution of the contract (resource block price) proposed by the base station can not only maximize the benefit of the base station, but also ensure the participation of users , Improve resource utilization.
[0091] First of all, individual rationality ensures that user benefits are non-negative, namely:
[0092] V(θ,b,p)=R(θ,b,p)-π(b,p)≥0
[0093] Secondly, incentive compatibility guarantees that the contract proposed by the base station is the optimal contract that this type of user can obtain the most benefit, namely:
[0094] R(θ,b(θ),p(θ))-π(b(θ),p(θ))≥R(θ,b(θ′),p(θ′))-π(b(θ) ′), p(θ′))
[0095] So far, we believe that as long as the contract designed by the base station for a specific user meets these two constraints, then the contract is feasible.
[0096] 4) Analyze the necessary conditions for the feasibility of the contract and give proof;
[0097] When the base station proposes a contract, in addition to the two constraints mentioned above, the following four necessary conditions must also be met.
[0098] Condition 1: Under normal circumstances, the number of users in the network cell we set to consider is limited and discrete.
[0099] And satisfy:
[0100] θ 1 2 i K
[0101] In particular, when the transmission rate required by a certain type of user is constant, the present invention establishes a numerical constraint relationship for the bandwidth and power related to the resource block, such as image 3 As shown, namely:
[0102] b·p=ζ
[0103] by image 3 It can be seen that the ζ value of the base station and the user are different.
[0104] Condition 2: Any feasible contract C={b(θ), p(θ), π(θ)}, if and only if π i ≥π j , Satisfy b i ≥b j;
[0105] Condition 3: Any feasible contract C={b(θ), p(θ), π(θ)}, if θ is satisfied iθ j , Then b ib j;
[0106] Condition 4: Any feasible contract C={b(θ), p(θ), π(θ)}, when user k=2, 3,..., K, satisfies
[0107] π k-1 +X≤π k ≤π k-1 +Y
[0108] The values of X and Y are expressed as follows:
[0109] x=R(θ k-1 , B k , P k )-R(θ k-1 , B k-1 , P k-1 )
[0110] Y=R(θ k , B k , P k )-R(θ k , B k-1 , P k-1 )
[0111] 5) Derive the corresponding increase preference attribute and find the solution of the optimal contract.
[0112] A feasible contract must make the user's data transmission rate have important attributes, that is, for a given contract item increment, the rate increment of higher types of users is greater than that of lower types of users, which we define as increased preference Property (IP), that is, for any θ>θ′, b>b′ and p
[0113] R(θ,b,p)-R(θ,b′,p′)>R(θ′,b,p)-R(θ′,b′,p′)
[0114] According to this property, we can easily find the solution of the optimization problem, that is, the price of the resource block:
[0115]
[0116] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications are also It should be regarded as the protection scope of the present invention.
