WO2017109577A1

WO2017109577A1 - Self-organization and self-optimization method and apparatus for an ultra-dense network

Info

Publication number: WO2017109577A1
Application number: PCT/IB2016/001938
Authority: WO
Inventors: Haiyou Guo; Feng She
Original assignee: Alcatel Lucent
Priority date: 2015-12-25
Filing date: 2016-12-12
Publication date: 2017-06-29
Also published as: CN106921985A; CN106921985B

Abstract

The present disclosure provides a self-organization and self-optimization method and apparatus for an ultra-dense network, wherein the self-organization method for a probing link comprises: transmitting, by a probing link, a probing signal at a fixed power; when a locally measured Signal to Interference plus Noise Ratio SINR of an active link in the ultra-dense network converges to a constant, obtaining, by the probing link, a maximal achievable SINR of the probing link based on the locally measured current SINR, a Signal Noise Ratio SNR, and a currently achieved maximal value of power normalized, so as to cause the probing link to determine whether to access the ultra-dense network. By adopting an autonomous procedure through a probing link intended to access to an ultra-dense network and an active link in the ultra-dense network, the probing link may decide whether to access to the ultra-dense network according to the obtained maximal achievable SINR, which reduces power consumption while assuring a higher unit area spectrum efficiency, thereby efficiently utilizing the network resources.

Description

SELF-ORGANIZATION AND SELF-OPTIMIZATION METHOD AND APPARATUS FOR AN ULTRA-DENSE

NETWORK

FIELD OF THE INVENTION

[0001] The present invention relates to the field of network communication, and more specifically relates to a self-organization and self-optimization method and apparatus for an ultra-dense network.

BACKGROUND OF THE INVENTION

[0002] Currently, the study on the 5^th generation of mobile communication technologies (shortly referred to as 5G) has become gradually heated worldwide, wherein network densification with universal resources reuse capability is recognized as one of indispensable solutions in 5G technologies. As network densification approaches to extremity, ultra-dense networks (UDNs) will not be formed by regular hexagonal cells; but are formed by distorted and overlapping areas especially in a case of inhomogeneous traffic distribution and random network topology. For such a UDN with a universal frequency reuse capability, it is impractical to regulate in advance an interference mode and to plan network capacity and coverage; instead, a self-organization and self-optimization procedure that may be implemented on-line is needed to perform channel access control and interference control. An objective of designing this method lies in matching spatially and temporally, in a cognitive way, wireless resources that are underutilized based on change of traffic demands. In order to cope with explosive growth in User Equipment (UE) population and demanding rates per UE, a UDN is required to conduct network-wide coordination amongst tens or hundreds of UEs sharing a same channel. However, since feedback and interaction with respect to channel state information and network scheduling decision information suffers practical limitations imposed by a signaling and backhaul network, such large-scale coordination can hardly be implemented in a centralized manner. In practice, it is preferred to carry out network-wide self-organization and self-optimization in a distributed and autonomous fashion, whereby respective links in the network can reach a consensus on access and resource configuration decisions based on local measurements and a few signaling exchanges.

SUMMARY OF THE INVENTION

[0003] The self-organization and self-optimization method and apparatus for an ultra-dense network according to the present invention implements an autonomous procedure, such that a probing link may decide whether to access the ultra-dense network based on a maximal achievable SINR as achieved.

[0004] One embodiment comprises a self-organization method for a probing link in an ultra-dense network, comprising:

[0005] transmitting, by a probing link, a probing signal at a fixed power;

[0006] when a locally measured Signal to Interference plus Noise Ratio of an active link in the ultra-dense network converges to a constant, obtaining, by the probing link, a maximal achievable SINR of the probing link based on the locally measured current SINR, a Signal Noise Ratio SNR, and a currently achieved maximal value of power normalized, so as to cause the probing link to determine whether to access the ultra-dense network.

[0007] A self-organization method for an active link in an ultra-dense network according to another embodiment, when a probing link transmits a probing signal at a fixed power, comprises:

[0008] updating, by each active link, a transmit power of a next time according to their respective target signal-to-interference plus noise ratio SINR, current SINR as locally measured, normalized noise power value as locally measured, current transmit power value, and current power normalized maximal value; [0009] iteratively updating, by each active link according the updating the transmit power of the next time, its transmit power with time, till the local measured SINR value of the active link is converged to a constant.

[0010] A self-organization and self-optimization method for an ultra-dense network according to another embodiment, comprising:

[0011] transmitting, by each active link, a probing signal at a fixed power;

[0012] updating, by each active link, a transmit power of a next time according to their respective target signal-to-interference plus noise ratio SINR, current SINR as locally measured, normalized noise power value as locally measured, current transmit power value, and current power normalized maximal value;

[0013] iteratively updating, by each active link according the updating the transmit power of the next time, its transmit power with time, till the local measured SINR value of the active link is converged to a constant; then the probing link obtains a maximal achievable SINR of the probing ink based on the current SINR as locally measured, the Signal Noise Ratio SNR, and the current power normalized maximal value; when the maximal achievable SINR is greater than or equal to a target SINR of the probing link, the probing link as an active link accessing the ultra-dense network; and

[0014] updating, by the probing link and the active link, their respective transmit powers according to their own target SINRs, current SINRs as locally measured, current transmit power values, and current power normalized maximal values, till each working SINR of the probing link and the active link is greater than their respective target SINRs.

[0015] Another embodiment comprises a self-organization apparatus for a probing link in an ultra-dense network, comprising:

[0016] a transmitter of a probing link, for transmitting a probing signal at a fixed power;

[0017] a receiver of the probing link, for, when a locally measured Signal to Interference plus Noise Ratio of an active link in the ultra-dense network converges to a constant, obtaining a maximal achievable SINR of the probing link based on the locally measured current SINR, a Signal Noise Ratio SNR, and a currently achieved maximal value of power normalized, so as to cause the probing link to determine whether to access the ultra-dense network.

[0018] A self-organization apparatus for an active link in an ultra-dense network according to another embodiment comprises:

[0019] A power updater for self-organization for, when a probing link transmits a probing signal at a fixed power, updating, by each active link, a transmit power of a next time according to their respective target signal-to-interference plus noise ratio SINR, current SINR as locally measured, normalized noise power value as locally measured, current transmit power value, and current power normalized maximal value; and iteratively updating, by each active link according the updating the transmit power of the next time, its transmit power with time, till the local measured SINR value of the active link is converged to a constant.

[0020] A self-organization and self-optimization apparatus for an ultra-dense network according to another embodiment, comprising:

[0021] a transmitter of a probing link, for transmitting a probing signal at a fixed power;

[0022] a power updater for self-organization, for, when the transmitter of the probing link transmits the probing signal, updating, by each active link, a transmit power of a next time according to their respective target signal-to-interference plus noise ratio SINR, current SINR as locally measured, normalized noise power value as locally measured, current transmit power value, and current power normalized maximal value; and iteratively updating, by each active link according the updating the transmit power of the next time, its transmit power with time, till the local measured SINR value of the active link is converged to a constant; then triggering a receiver of the probing link; [0023] the receiver of the probing link, for obtaining a maximal achievable SINR of the probing ink based on the current SINR as locally measured, the Signal Noise Ratio SNR, and the current power normalized maximal value;

[0024] an access controller of the probing link, for, when the maximal achievable SINR is greater than or equal to a target SINR of the probing link, accessing the probing link as an active link to the ultra-dense network; and

[0025] a power updater for optimization, for, when the access controller of the probing link controls the probing link as an active link to access to the ultra-dense network, updating, by the probing link and the active link, their respective transmit powers according to their own target SINRs, current SINRs as locally measured, current transmit power values, and current power normalized maximal values, till each working SINR of the probing link and the active link is greater than their respective target SINRs.

[0026] The embodiments of the present invention adopt an autonomous procedure through a probing link intended to access to an ultra-dense network and an active link in the ultra-dense network, such that the probing link may decide whether to access to the ultra-dense network according to the obtained maximal achievable SINR, which reduces power consumption while assuring a higher unit area spectrum efficiency, thereby efficiently utilizing the network resources.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[0027] The present invention will be understood more thoroughly through the detailed depictions and the accompanying drawings infra, wherein the same units are presented by the same reference numerals; the drawings are only provided for illustration, not intended to limit the present invention, wherein:

[0028] Fig. 1-1 illustrates a system diagram where L-l active links, one probing link, and M external links are superimposed on a common radio channel.

[0029] Fig. 1-2 illustrates a structural diagram of a time frame in a self-organization and self-optimization method for an ultra-dense network according to one exemplary embodiment.

[0030] Fig. 1-3 illustrates a structural diagram of a time frame in which link 1, link 2, link 3, and link 4 sequentially probe an access network one by one in a self-organization and self-optimization method for an ultra-dense network according to an exemplary embodiment.

[0031] Fig. 2 illustrates a flow diagram of a self-organization method for a probing link in an ultra-dense network according to one exemplary embodiment.

[0032] Fig. 3 illustrates a flow diagram of step S220 in the self-organization method for a probing link in an ultra-dense network according to one exemplary embodiment.

[0033] Fig. 4 illustrates a flow diagram of a self-organization method for an active link in an ultra-dense network according to one exemplary embodiment.

[0034] Fig. 5 illustrates a flow diagram of a self-organization and self-optimization method for an ultra-dense network according to one exemplary embodiment.

[0035] Fig. 6 illustrates a flow diagram of a self-organization and self-optimization method for an ultra-dense network according to another exemplary embodiment.

[0036] Fig. 7 illustrates a flow diagram of a self-organization and self-optimization method for an ultra-dense network according to a further exemplary embodiment.

[0037] Fig. 8 illustrates a structural block diagram of a self-organization apparatus for a probing link in an ultra-dense network according to one exemplary embodiment.

[0038] Fig. 9 illustrates a structural block diagram of a self-organization and self-optimization apparatus for an ultra-dense network according to one exemplary embodiment. [0039] Fig. 10 illustrates a functional module diagram of a self-organization and self-optimization apparatus for an ultra-dense network according to one exemplary embodiment.

[0040] Fig. 11-1 illustrates a working diagram of a self-organization and self-optimization apparatus for an ultra-dense network according to one exemplary embodiment during a self-organization interval of access control according to one exemplary embodiment.

[0041] Fig. 11-2 illustrates a working diagram of a self-organization and self-optimization apparatus for an ultra-dense network according to one exemplary embodiment during a self-organization interval of power control according to one exemplary embodiment.

[0042] Fig. 12 illustrates a CDF curve of iteration times after the self-organization and self-optimization method and apparatus for an ultra-dense network is subjected to 1870 experiments according to one exemplary embodiment, where the transverse coordinate represents iteration times, and the longitudinal coordinate represents empirical probabilities.

[0043] Fig. 13 illustrates a CDF curve of maximal achievable SINR errors after the self-organization and self-optimization method and apparatus for an ultra-dense network is subjected to 1870 experiments according to one exemplary embodiment, where the transverse coordinate represents error absolute values (unit: dB), and the longitudinal coordinate represents empirical probabilities.

[0044] Fig. 14 illustrates an evolution process of per- link working SIN R when 5 internal links in a UDN comprising 5 internal links and 2 external links sequentially access to a common radio channel one by one, wherein the 1^st, 3^rd, and 5^th circles from the left represent self-organization intervals of access control, the 2^nd, 4^th, and 6^th circles from the left represent self-optimization intervals of power control, the transverse coordinate represents time, the longitudinal coordinate represents working SIN R (dB); the 5 internal links are link 1 denoted by reference sign a, link 2 denoted by reference sign b, link 3 denoted by reference sign c, link 4 denoted by reference sign d, and link 5 denoted by reference sign e.

[0045] Fig. 15 illustrates an evolution process of per- link transmit power when 5 internal links in a UDN comprising 5 internal links and 2 external links sequentially access to a common radio channel one by one, wherein the 5 internal links are link 1 denoted by reference sign a, link 2 denoted by reference sign b, link 3 denoted by reference sign c, link 4 denoted by reference sign d, and link 5 denoted by reference sign e.

[0046] Fig. 16 illustrates an evolution process of normalized outward interference powers of 2 external links when 5 internal links in a UDN comprising 5 internal links and 2 external links sequentially access to a common radio channel one by one, wherein the 2 external links are external link 1 denoted by reference sign k and external link 2 denoted by reference m.

[0047] It should be mentioned that these drawings intend to illustrate general characteristics of the methods, structures and/or materials used in some exemplary embodiments, and to make supplementations to the written depictions provided infra. However, these drawings are not drawn in proportion and might not accurately reflect a precise structure or performance feature of any given embodiment, and should not be interpreted as defining or limiting the scope of numerical values or attributes covered by exemplary embodiments. In various drawings, similar or complete identical reference numerals are used to indicate existence of similar or completely identical units or features. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0048] Although exemplary embodiments may have various modified and alternative manners, one some embodiments thereof are illustrated exemplarily, which will be described in detail here. However, it should be understood that the exemplary embodiments are not intended to be limited to the disclosed specific forms; on the contrary, the exemplary embodiments are intended to cover all modifications, equivalent solutions, and alternative solutions within the scope of the claims. Same reference numerals constantly refer to same units in depiction of respective drawings.

[0049] It should be mentioned before discussing the exemplary embodiments in more detail that some exemplary embodiments are described as processing or methods in the form of flow diagrams. Although a flow diagram depicts respective operations as being sequentially processed, many operations therein may be implemented in parallel, concurrently or simultaneously. Besides, various operations may be re-ordered. When the operations are completed, the processing may be terminated. However, there may comprise additional steps not included in the accompanying drawings. The processing may correspond to a method, a function, a specification, a sub-routine, a sub-program, etc.

[0050] The term "wireless device" or "device" used here may be regarded as synonymous to and will be sometimes referred to hereinafter as the following items: client, user equipment, mobile station, mobile user, mobile terminal, subscriber, user, remote station, access terminal, receiver, mobile unit, etc., which may also describe a remote user of wireless resources in a wireless communication network.

[0051] The methods discussed infra (some of which are illustrated through flow diagrams) may be implemented through hardware, software, firmware, middleware, microcode, hardware description language or any combination thereof. When they are implemented with software, firmware, middleware or microcode, the program code or code segment for executing essential tasks may be stored in a machine or a computer readable medium (e.g., storage medium). (One or more) processors may implement essential tasks.

[0052] The specific structures and function details disclosed here are only representative, for a purpose of describing the exemplary embodiments of the present invention. Instead, the present invention may be specifically implemented through many alternative embodiments. Therefore, it should not be appreciated that the present invention is only limited to the embodiments illustrated here.

[0053] The terms used here are only for describing preferred embodiments, not intended to limit exemplary embodiments. Unless otherwise indicated, singular forms "a" or "one" used here further intends to include plural forms. It should also be appreciated that the terms "comprise" and/or "include" used here prescribe existence of features, integers, steps, operations, units and/or components as stated, but do not exclude existence or addition of one or more other features, integers, steps, operations, units, components, and/or a combination thereof.

[0054] It should also be noted that in some alternative embodiments, the functions/actions as mentioned may occur in an order different from what is indicated in the drawings. For example, dependent on the functions/actions involved, two successively illustrated diagrams may be executed substantially simultaneously or in a reverse order sometimes.

[0055] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meanings as generally understood by those skilled in the art within the field of the exemplary embodiments. It should also be understood that unless explicitly defined here, those terms defined in a typical dictionary should be interpreted to have a meaning consistent with that in a context of a relevant field, and should not be interpreted according to an ideal or over formal meaning.

[0056] Hereinafter, the present invention will be described in further detail with reference to the accompanying drawings.

[0057] A system diagram of the embodiments of the present invention is shown in Fig. 1-1. The system has L-l active links (denoted as link 1, 2, L-l), a probing link (denoted as L), and M external links, which are superimposed on a common radio link, wherein the L-l active links and the probing link perform transmission of traffics. Each active link, the probing link, and the external links have a respective transmitter and receiver.

[0058] A self-organization and self-optimization method for an ultra-dense network according to the present invention comprises two intervals: a self-organization interval for access control of the ultra-dense network, and a self-optimization interval for power control of the ultra-dense network. Within the self-organization interval for access control of the ultra-dense network, the probing link transmits a probing signal at a fixed power, and when the locally measured SIN R of an active link converges to a constant, the probing link achieves a maximal achievable SINR. Meanwhile, the active link iteratively updates its transmit power so as to realize convergence of its locally measured SINR into a constant. At the end of the self-organization interval for access control of the ultra-dense network, if the maximal achievable SI NR obtained by the probing link is greater than or equal to its target SIN R, the probing link decides whether it may perform access as an active link allowed to access. After the original probing link accessing the network as an active link, during the self-optimization interval for power control of the ultra-dense network, the system has L active links and M external links superimposed on the common radio channel, wherein the L active links perform transmission of traffics, and each active link and external link have a respective transmitter and receiver. Within the self-optimization interval for power control of the ultra-dense network, the L active links iteratively update their transmit powers and stop update of the transmit powers till all of the working SIN Rs of the L active links are greater than their respective target SIN Rs, so as to automatically reach an appropriate power configuration to satisfy a precondition for non-intrusiveness of ALP (Active Link Protection). The ALP condition is

SINR, (p) = -_L ^ ≥fi , 1 = 1, 2, - , L

∑^GaP_k + ⁿi

ALP condition: ∑^_MJPL≤P_M, m = \, 2,- M

0 < Ρ_!≤Ρ_Μ+1 , 1 = 2, - , L B P

where denotes a transmit power of the link /, denotes a target SINR of the link /, ^m (m=l, p

2, M) denotes an acceptable interference power upper limit of the link m, ^M+l (I = 1, 2, L) denotes a maximal allowable transmit power of the link /, ^lk denotes a channel gain from a transmitter of the link k n

to a receiver of the link /, ' denotes a background noise power of the receiver of the link / determined w

according to thermal noise and external link interference, ^m- denotes a channel gain of the receiver from

P ~ \ P P ' ' ' p i

the transmitter of the link / to the external link m, and ^{1 1 2 L 1} .

[0059] A time frame structure of the ultra-dense network according to the embodiment of the present invention may be as shown in Fig. 1-2. One frame comprises three consecutive intervals for different purposes, i.e., an self-organization interval for access control of the ultra-dense network, a self-optimization interval for power control of the ultra-dense network, and a trivial interval, wherein during the trivial interval, all links that are allowed to access to the ultra-dense network transmit data signals when no power is updated. As shown in Fig. 1-3, the system shown in Fig. 1-1 desires to superimpose as much links as possible over the common radio channel in sequence.

[0060] Fig. 2 illustrates a flow diagram of a self-organization method for a probing link in an ultra-dense network according to one embodiment of the present application.

[0061] As illustrated in Fig. 2, the self- self-organization method for a probing link in an ultra-dense network according to the present embodiment comprises steps of:

[0062] S210: transmitting, by the probing link, a probing signal at a fixed power;

[0063] S220: when a locally measured Signal to SIN R (Interference plus Noise Ratio) of an active link in the ultra-dense network converges to a constant, obtaining, by the probing link, a maximal achievable SIN R of the probing link based on the locally measured current SINR, a Signal Noise Ratio SN R, and a currently achieved maximal value of power normalized, so as to cause the probing link to determine whether to access the ultra-dense network..

[0064] Hereinafter, respective steps will be further introduced in detail.

[0065] In step S210, one common radio channel in the ultra-dense network at least have one active link that has accessed to the network and at least one external link to implement co-existence satisfying the ALP condition; the probing link is a new active link intended to access to the ultra-dense network.

[0066] As illustrated in Fig. 3, the operation performed by the probing link in S220 is step S2207 where the procedure of determining that the locally measured SIN R of the active link in the ultra-dense network is converged to a constant consists of steps S2201-S2206:

[0067] S2201: a receiver of each active link / (1=1, 2, ... L-1) feeds back the locally measured normalized _____

noise power value ^*¹¹ to its corresponding transmitter, where ^ denotes a power of background noise of the receiver of the active link / accounting for a total effect of thermal noise plus the interference due to external links, and ¹¹ denotes a channel gain from the transmitter of the active / to the receiver of the active link /.

[0068] S2202: the receiver of each active link / (1=1, 2, ... L-1) feeds back the locally measured current SIN R

. SINR_t (t) . . _t ._t .. _t . .

value ' back to its corresponding transmitter, wherein

,

P (t)

where denotes a transmit power of the current active link / (1=1, 2, ... L-1), and P ^L denotes the fixed power of the probing link L.

[0069] S2203: broadcasting, over a specific channel, the normalized outward interference power

— I f

of each external link m (m=l, 2, M), where ^m denotes an acceptable interference power upper limit of the external link m, ^WmJ denotes a channel gain from the transmitter of the probing link L to the receiver of the external link m.

P +l ,normal ( Vt) ' = p -

[0070] S2204: broadcasting, over a specific channel, a normalized transmit power ^M+l p

of each active link /, where ^{M +l} denotes a maximal allowable transmit power of the active link /.

[0071] S2205: updating, by the transmitter of each active link /, the transmit power of a next time to ma k^W}

SINR^t) ¹ G_l n=l,2,- - -,M+L

where ^l denotes a target SIN R of the

,™ \ ^Ρη,ηοηηαΐ(ί }

active link /, " ^- +^L denotes a current power normalized maximal value.

[0072] Specifically, the current power normalized maximal value " ^- +^L includes: a

P (t)

largest value among a normalized transmit power , normal _t„ L-1) of each active link in the

P (t)

ultra-dense network, a normalized transmit power M+L,normai _Qf _tne p_robj_ng \ _n^ _anc| _a normalized

P At)

outward interference power ^m'^{normal x} ' (m=l, 2, M) of each external link in the ultra-dense network. [0073] S2206: if SINR_t(t) 52202 is converged to a constant, performing step S2207; otherwise, iteratively repeating steps S2202~S2205 in a t=t+l fashion.

[0074] S2207: obtaining, by the probing link, a maximal achievable SINR based on the locally measured current SIN R, SNR, and current power normalized maximal value, such that the probing link decides whether to access the ultra-dense network. Specifically, the obtained maximal achievable SINR includes

, w .here B^L* t ..he maxima .l ac .h.ieva .b.le _C S₁I_MN _DR of the pro .b.ing link, SINR_L t) _£j_{enotes tne} |_oca||y measured current SIN R value of the probing link, i.e.,

SINR_L(t) = - ^Gu-^Pl

∑^^( +¾ _SNR

k⁼¹ , ^L denotes the locally measured SNR value of the probing link, i.e.

[0075] As illustrated in Fig. 4, a self-organization method for an active link in an ultra-dense network according to the present invention comprises steps of: [0076] S410: update, by each active link, a transmit power of a next time according to their respective target SINR, current SINR as locally measured, normalized noise power value as locally measured, current transmit power value, and current power normalized maximal value.

[0077] Specifically, the transmitter of each active link / updates the transmit power of the next time to

where ^l denotes a target SINR of the active link /, SIN^ if) ^_enQ^_{es tne} |_oca||y measured current SINR value of the active link /, i.e.,

SINR_l (t)

denotes the transmit power of the current active link /,

¹¹ denotes the locally measured normalized noise power value of the active link /, and

denotes the current power normalized maximal value.

[0078] Specifically, the current power normalized maximal value includes a

P (t)

largest value among the normalized transmit power M+I, normal _t„ L-1) of each active link in the

P (t)

ultra-dense network, the normalized transmit power M+L,normai _Qf _tne p_robj_ng \ _n^ _anc| t_ne normalized outward interference power ^m'^{nonmu x} ' (m=l, 2 ... M) of each external I ink in the ultra-dense network;

P (t) P

wherein ^' denotes the transmit power of the current active link /, ^{M +l} denotes a maximal allowable transmit power of the active link I; wherein ^+L

denotes the maximal allowable transmit power of the probing link; wherein

, where denotes an acceptable interference power upper limit of the external m, ^WmJ denotes a channel gain from a transmitter of the active link / to the receiver of w

the external link m, ^{m i} denotes a channel gain from the transmitter of the probing link L to the receiver of the external link m.

[0079] S420: if the SINR_t (t) ^ active link 1(1=1, 2, ... L-1) is converged to a constant, performing step S430; otherwise, iteratively repeating step S410 in a t=t+l fashion.

[0080] S430: obtaining, by the probing link, a maximal achievable SINR of the probing link based on the locally measured current SIN and SNR and the current power normalized maximal value, so as to cause the probing link to determine whether to access the ultra-dense network.

[0081] In conjunction with Fig. 5, a self-organization and self-optimization method for an ultra-dense network according to the present embodiment comprises steps of:

p

[0082] S510: transmitting, by a probing link, a probing signal at a fixed power ^L ;

[0083] Further, the normalized transmit power

of the probing link is broadcast over a specific channel.

[0084] tive link 1(1=1, 2, ... L-l), a transmit power

A (' + l) {Ρ„_>Βοπηα/ ( } -1

of a next time according to their respective target SINR, current SINR as locally measured, normalized noise power value as locally measured, current transmit power value, and current power normalized maximal value;

[0085] S530: if the ^^z (^) ₀f _each active link 1(1=1, 2, ... L-l) is converged to a constant, performing step S540; otherwise, iteratively repeating step S520 in a t=t+l fashion.

[0086] S540: obtaining, by the probing link, a maximal achievable SINR ?^* = = — based on the locally measured current SIN and Signal

1 max _T {P_ntnmnal (t)} - l

n=l,2,- - -,M +L

- +

SINR_L (t) SNR_L

Noise Ratio SNR and the current power normalized maximal value.

[0087] S550: when the maximal achievable SINR is greater than or equal to the target SINR of the probing link, accessing, by the probing link as an active link, the ultra-dense network.

[0088] S560: updating, by the probing link and the active link, their respective transmit powers according to their own target SINRs, current SINRs as locally measured, current transmit power values, and current power normalized maximal values, till each working SINR of the probing link and the active link is greater than their respective target SINRs.

[0089] In conjunction with Fig. 6, optionally, the step S560 may be implemented through the following method:

[0090] S610: updating, by each active link k (k=l, 2, L-l, L) including the probing link, a transmit power

P_k (t + l) =— &— p_k (t)

SINR (t)

k ^ (k=l, 2, L-l, L) at (t+1) time according to their respective target SINR, locally measured current SINR, and current transmit power value, where denotes a transmit power of the current active link k, ^k denotes a target SINR of the active link k, denotes the locally measured SINR_k (t) current SIN R value of the active link k, i.e.,

;

[0091] S620: determining, by each active link k, a transmit power

at the (t+l) time and the power normalized maximal value " ^1>Z>- - -^>M +L, _{at tne} time, wherein the power normalized maximal value at the (i+1) time is a larger value in the normalized transmit power +k, normal (^{t +} ^ ^_{=lj 2j} L-l, L) of each active link k at (i+1) time and the normalized outward

P , 0 + 1)

interference power ^m'^normal (m=l, 2, M) of each external link in the ultra-dense network at (i+1)

time; wherein

, Pk^k«+ denoting the transmit power of the active link k at p

time (i+1), and ^{M +k} denoting the maximal allowable transmit power of the active link k; wherein

, where ^m denotes an acceptable interference power upper limit of the external link m, and ^m<k denotes a channel gain from the transmitter of the active link k to the receiver of the external link m.

SINR_k(t)

[0092] S630: if of each active link k is converged to a constant, the method ends; otherwise, steps S610 ~ S620 are executed in a i=i+2 fashion.

[0093] In conjunction with Fig. 7, the self-organization optimizing method for an ultra-dense network according to the present embodiment comprises the following execution procedures:

[0094] S701: setting t=0, and an initial transmit power of a transmitter of each active link / (1=1, 2, L-l) not zero;

[0095] S702: transmitting, by a probing link, a robing signal at a fixed power P_L, and broadcasting, over a specific channel, a normalized transmit power

of the probing link;

A.

[0096] S703: feeding back, by a receiver of each active link / (1=1, 2, L-l), ¹¹ to its corresponding transmitter;

[0097] S704: feeding back, by the receiver of each active link /, SINR_j'it) to its corresponding transmitter; [0098] S705: broadcasting, over tthhee ssppeecciiffiicc cchhaannnneell,,

each external link m (m=l, 2, M);

P M +l ,normal (t) ' = p -

[0099] S706: broadcasting, over the specific channel, ^M+l of each active link /;

[0100] S707: updating, by the transmitter of each active link /, transmit power of a next time to

[0101] S708: if the ' of each active link / in step S704 is converged to a constant, performing step S709; otherwise, iteratively repeating steps S704 ~ S707 in a f=f+l fashion;

[0102] S709: obtaining, by the probing link L, a maximal achievable SINR as

1 n=l,2,- - -M ,- - -M +l,- - -M +L

- +

SINRAt) SNR₇ .. _t SINRM) SNR_L .

^L ' ^L according to , , and

[0103] S710: when the maximal achievable SINR is greater than or equal to a target SINR of the probing link L, accessing, by the probing link L as an active link, the ultra-dense network;

[0104] S711: feeding back, by the receiver of each active link k (k=l, 2, L-l, L) including the probing link,

SINR_k (t) _t ._t .. _t

k to its corresponding transmitter;

[0105] S712: updating, by each active link k (k=l, 2, L-l, L), the transmit power of the (f+1) time to p_k (t + l) =— ^ p_k (t), k = 1, 2, - , L - l, L

[0106] S713: broadcasting, over the specific channel,

₀f _eacn external link m at (f+1) time;

P ¹ M+k , normal

[0107] S714: broadcasting, over the specific channel,

of each active link k at (t+l) time;

[0108] S715: determining, by each active link k, its transmit power

and n=l,2,- - -, +L.

[0109] S716: if ^¹¹ "¹^ ^^ of each active link /: in step S711 is converged to a constant, the method ends; otherwise, iteratively performing steps S711~S715 in a f=f+2 fashion.

[0110] The system according to the embodiment of the present invention as shown in Fig. 1 also comprises a feedback channel and a specific channel besides the common radio channel, wherein the feedback refers to a feedback channel from the receiver of the a^th (including /, m, L or k) link to the transmitter of the transmitter of the a^th link, which, specifically for the a^th link, is to return the locally measured current SIN R and SNR value, the locally measured normalized noise power value, and the maximal achievable SINR value of the probing link. Particularly, the specific channel is for broadcasting the normalized outward interference power of each external link, the normalized transmit power of each active link, a normalized transmit power of the probing link, and the current power normalized maximal value.

[0111] An embodiment of the present invention further provides a self-organization apparatus for a probing link in an ultra-dense network, as illustrated in Fig. 8, comprising:

[0112] a transmitter 210 of a probing link, for transmitting a probing signal at a fixed power;

[0113] a receiver 220 of the probing link, for, when a locally measured Signal to Interference plus Noise Ratio of an active link in the ultra-dense network converges to a constant, obtaining a maximal achievable SIN R of the probing link based on the locally measured current SIN R, a Signal Noise Ratio SNR, and a currently achieved maximal value of power normalized, so as to cause the probing link to determine whether to access the ultra-dense network.

[0114] Specifically, the maximal achievable SINR is determined as:

[0115] The embodiment of the present further provides a self-organization apparatus for an active link in an ultra-dense network, comprising:

[0116] A power updater for self-organization for, when a probing link transmits a probing signal at a fixed power, updating, by each active link, a transmit power of a next time according to their respective target signal-to-interference plus noise ratio SINR, current SIN R as locally measured, normalized noise power value as locally measured, current transmit power value, and current power normalized maximal value; and iteratively updating, by each active link according the updating the transmit power of the next time, its transmit power with time, till the local measured SINR value of the active link is converged to a constant.

_Pl (t + l) = ^βι _Pl (t) + ^ max

n=l,2,- - -,M+L {P„_>Bi ( } Specifically, update the transmit power to SINR_t (t) G_u

[0117] An embodiment of the present invention further provides a self-organization and self-optimization apparatus for an ultra-dense network, as illustrated in Fig. 9, comprising:

[0118] a transmitter 210 of a probing link, for transmitting a probing signal at a fixed power;

[0119] a power updater 910 for self-organization, for, when the transmitter 210 of the probing link transmits the probing signal, updating, by each active link, a transmit power of a next time according to their respective target signal-to-interference plus noise ratio SIN R, current SINR as locally measured, normalized noise power value as locally measured, current transmit power value, and current power normalized maximal value; and iteratively updating, by each active link according the updating the transmit power of the next time, its transmit power with time, till the local measured SINR value of the active link is converged to a constant; then triggering a receiver 220 of the probing link;

[0120] the receiver 220 of the probing link, for obtaining a maximal achievable SINR of the probing ink based on the current SINR as locally measured, the Signal Noise Ratio SNR, and the current power normalized maximal value;

[0121] an access controller 920 of the probing link, for, when the maximal achievable SINR obtained by the receiver 220 of the probing link is greater than or equal to a target SINR of the probing link, accessing the probing link as an active link to the ultra-dense network; and

[0122] a power updater 930 for optimization, for, when the access controller 920 of the probing link controls the probing link as an active link to access to the ultra-dense network, updating, by the probing link and the active link, their respective transmit powers according to their own target SINRs, current SINRs as locally measured, current transmit power values, and current power normalized maximal values, till each working SINR of the probing link and the active link is greater than their respective target SINRs.

[0123] Further, the access controller 920 of the probing link is provided in the transmitter 210 of the probing link. The power updater 910 for self-organization and the power updater 910 for self-organization and the power updater 930 for self-optimization according to the embodiments of the present invention may be two different power updaters provided in the transmitter of the active link or may be the same power updater for conducting different update operations during the self-organization interval and the self-optimization interval. In other words, the power updater 910 for self-organization is provided in the transmitter of the active link, while the power updater 930 for self-optimization is provided in the transmitters of the probing link and active link; or a power updater is provided in respective transmitter of both of the active link and the probing link, such that during the self-organization interval of access control, the power updater in the transmitter of the active link in the ultra-dense network works using the computing method of the power updater 910 for self-organization; while during the self-optimization period for power control, the power updater in the transmitters of the probing link and active link in the ultra-dense network works using the computing method of the power updater 930 for self-optimization.

[0124] The self-organization and self-optimization apparatus for an ultra-dense network according to the embodiments of the present invention may also comprise:

[0125] a power normalized maximal value broadcaster for determining and broadcasting the current power normalized maximal value, the current power normalized maximal value

includes: a largest value among the normalized transmit power M +1 normal it)

(1=1, 2, L-l) of each active link in the ultra-dense network, the normalized transmit power

of the probing link, and the

P it)

normalized outward interference power (m=l, 2 ... M) of each external link in the ultra-dense

P (t) = -

^M+" P_M+L p_t (t)

network; wherein ^M+l , ¹ denotes the transmit power of the current active link /, , P_L

denotes the fixed power, ^{M +L} denotes the maximal allowable transmit power of the probing link; wherein

denotes an acceptable interference power upper limit of the external m, denotes a channel gain from a transmitter of the active link / to the receiver of w

[0126] Specifically, the power normalized maximal value broadcaster is neither in the transmitter and receiver of the probing link, nor in the transmitter and receiver of the active link; instead, it is standalone in the apparatus.

[0127] Based on the system diagram as illustrated in Fig. 1, when the power updater 910 for self-organization and the power updater 930 for self-optimization adopt the same power updater 1010, the structural diagram of all functional modules of the self-organization apparatus for the ultra-dense network may be as shown in Fig. 10, the working diagram of the self-organization interval of access control may be as shown in Fig. 11-1, and the working diagram of the self-optimization interval for power control may be as shown in Fig. 11-2.

[0128] As shown in Fig. 10, a power amplifier in the transmitter of each link adjusts an amount of transmit power according to output of the power updater 1010. The power updater 1010 may output any value of a fixed power, zero value (a value outputted when the probing link exits at the end of the self-organization interval for access control), Pⁱ ^ ^ ^ P^k (f _{/ anc}| P^k (f ^~*^~ ¾ j_ne access controller 920 of the probing link is for indicating the probing link to output a "probing" instruction at the start of the self-organization interval for the access control; when the maximal achievable SINR of the probing link is greater than or equal to a target SINR of the probing link, indicating the probing link to output an "access" instruction at the end of the self-organization interval for the access control; when the maximal achievable SINR of the probing link is less than the target SIN R of the probing link, indicating the probing link to output an "exit" instruction at the end of the self-organization interval for the access control. The target SINR of the probing link or active link is stored through a memory in respective transmitter. The locally measured SINR of the probing link or active link is obtained through an SINR estimator in respective receiver. The locally measured SN R of the probing link is obtained through an SNR estimator in its receiver. The locally measured normalized noise power value of the active link is obtained through a normalized power noise estimator in its receiver. The maximal achievable SINR of the probing link is achieved through the maximal achievable SINR calculate in its receiver. The normalized outward interference power measured by each external link is obtained through a total interference normalized value estimator in its receiver. A power management module in the transmitter of the active link calculates a ratio between the current transmit power and the maximal allowable transmit power according to the current transmit power to output a normalized transmit power value.

[0129] Fig. 11-1 shows a working diagram of a self-organization interval for access control. At the start of the interval, the access controller 920 in the transmitter of the probing link outputs a "probing" instruction

p

to the power updater 1010; the power updater 1010 outputs a constant value ^L to the power amplifier; therefore, the probing signal may be a predetermined training sequence for estimating the SIN R and the SNR, or may carry some basic information such as link ID; the power normalized maximal value broadcaster broadcast the normalized transmit power of the probing link. The access controller in the transmitter of the active link outputs an "access" instruction to a power updater; meanwhile, the memory in the transmitter of the active link outputs an "access" instruction to the power updater; meanwhile, the memory in the transmitter of the active link outputs the target SINR to the power updater; the power updater transmits a data signal with an initial power amount being Pi ^ A normalized noise power estimator in the receiver of the active link estimates a locally measured normalized noise power value and feeds it back to the power updater in the transmitter of the active link over a feedback channel. An iteration procedure within the self-organization interval comprises: estimating, by an SINR estimator in the receiver of the active link, a locally measured SINR, and feeding it back to the power updater in the transmitter of the active link over a feedback channel. A total interference normalized value estimator in the receiver of the external link estimates a normalized outward interference power and transmits it to the power normalized value broadcaster; a power management module in the transmitter of the active link calculates the normalized transmitter power and transmits it to the power normalized maximal value broadcaster; the power normalized maximal value broadcaster determines a largest value among the normalized transmit power of the probing link, the normalized transmit power of the active link, and the normalized outward interference power, and broadcasts it. The power updater in the active link transmitter updates the transmit power; if the updated locally measured SINR of each active link is converged to a constant, the self-organization interval of access control ends. At the end of the self-organization interval for access control, the normalized maximal value broadcaster broadcasts the current normalized maximal value; the SINR estimator and SNR estimator in the receiver of the probing link estimate the locally measured SINR and SNR, respectively; the maximal achievable SINR calculator in the receiver of the probing link calculates the maximal achievable SINR and feeds back the maximal achievable SINR to the access controller in the transmitter of the probing link over the feedback channel; the access controller, after comparing the maximal achievable SINR and the target SINR stored in the memory in the transmitter of the probing link, outputs an "access" instruction or an "exit" instruction to the power updater, such that the probing link enters into the power control self-optimization interval or the power updater outputs a zero value.

[0130] Fig. 11-2 shows a structural diagram of a self-optimization interval for power control. At the start of the interval, an access controller in a transmitter of the active link k including the probing link outputs an "access" instruction to the power updater, and the memory outputs the stored target SINR to the power updater; the power updater transmits a data signal with an initial power amount being Pk An iteration procedure within the self-optimization interval comprises: estimating, by an SINR estimator in the receiver of the active link k, a locally measured SINR, and feeding back to a power updater in the transmitter of the active link k through feedback information; updating, by the power updater in the transmitter of the active link k to P^k ^ ^~*^~ ^ , and outputting it to the power amplifier. A total interference normalized value estimator in the receiver of the external link estimates a normalized outward interference power and transmits to a power normalized maximal value broadcaster; a power management module in the transmitter of the active link k calculates a normalized transmit power and transmits it to the power normalized maximal value broadcaster; the power normalized maximal value broadcaster determines a larger value in the normalized transmit power of the active link k and the normalized outward interference power, and broadcasts it. The power updater in the transmitter of the active link k updates the transmit power; if the updated locally measured SINR of each active link k is converged to a constant, the self-optimization interval for power control ends.

[0131] Hereinafter, evaluation will be conducted on the performance of the self-organization and self-optimization method as provided. The evaluation procedure is specified below:

[0132] A UDN consisting of a plurality of internal links and two external links is simulated. The transmit powers of the internal links are constrained to a maximal transmit power limited by a power supply; meanwhile, they are also constrained by the requirements of the two external nodes with respect to the interference control. In an SINR-based power control, the effect due to fast fading is often assumed to be averaged out in power measurement or by diversity. Thus, the path gain of intended and interfering channels

G _ 4,

υ is modeled as ¹¹ , where ^lJ denotes a distance between the transmitter of the internal link / and the receiver of the internal link /.

[0133] Analogously, the channel gain from the transmitter of the internal link / to the receiver of the

A In, I

w m. ,l

d , , d ,

external link m may also be modeled as ^m'^L , wherein denotes a distance between the transmitter of the internal link I and the receiver of the external link m. Attenuation factors ^iJ and ^m-¹ simulate power variation due to shadowing effect that are supposed to be independently and identically log-normal distributed random variables with 0-dB expectation and 8-dB log-variance. The simulation parameters are detailed in Table 1. In order to plot the cumulative density function (CDF) curve, 1870 experiments are independently conducted.

Table 1

[0134] Fig. 12 measures a realization complexity of the proposed method using iteration times needed during the self-organization interval for access control. The average iteration times out of 1870 independent realizations is 46.6818. The possibility for the required times of iteration being less than 10 is 40%, while the possibility of larger than 100 times is 6%. Fig. 13 shows measuring the realization precision of the proposed method using an absolute error value between actual results and theoretical values. An average value of the absolute error values out of the 1870 experiments is 1.3058e-5dB. The possibility for the absolute error value being less than O.OOOldB is 98%. The simulation results prove that the algorithm procedure within the self-organization interval for access control according to the embodiment of the present invention has a high precision with a lower complexity.

[0135] Hereinafter, the self-organization and self-optimization method as provided is evaluated through an example of network scaling. The example simulates a UDN consisting of 5 internal links and 2 external links. Detailed simulation parameters are shown in Table 2. In the simulated experiment, the 5 internal links sequentially access the common radio channel. In order to observe the convergence performance of the algorithm, a length of the self-organization interval for access control and a length of the self-optimization interval for power control are not fixed. Besides, this example ignores the trivial interval. The numerical simulation experiments record an evolution procedure of the SINR, transmit power, and normalized outward interference power with time.

Table 2: Simulation Parameters for Network Scaling Example

Parameter Value

7.50599664200546e- 5

^Gu

1.09402818644240e -7

^G2\

2.67797750819099e-7

G₃₁

3.25641186987132e-9

G_4l

3.47999619000738e-7

G_5l

4.80563652331974e-08

^G\2

0.000146205594799049

^G22

6.01414112884575e-07

^G32

5.70169045197095e-06

^G42

8.17984204723367e-06

^G52

3.69554519764403e-06

^G13

4.08886322360479e-07

^G23

8.03699028672968e-09

^W2A

1.06046042320385e-08

^W2,5

Maximal transmit power of each 40 dBm

internal link

-20 dBm

P β 20+0-1)2 _dB

-23 dBm

n.

Probing power 20 dBm

[0136] Table 3 shows results of maximal achievable SINRs achieved during the self-optimization process for network access control. It precisely predicts maximal achievable SINRs of the probing link under a network APL condition. The maximal achievable SINRs of links 1, 2, 3, 4 exceed their target SINRs, respectively; then they are allowed to access the common radio channel and may reach their target SINRs. However, the maximal achievable SINR of the link 5 is lower than its target SINR. In the simulation experiments, link 5 abandons its target SINR 28 dB, while it is allowed to access the common radio channel β^* = 5 44

with ^{s '} as the target.

[0137] Fig. 14 shows an evolution process of each link SINR; variations of corresponding transmit powers and normalized outward interference power are shown in Figs. 15 and 16, respectively. In Fig. 14, the 1^st, 3^rd, and 5^th circles from the left represent a self-organization interval for access control, and the 2^nd, 4^th and 6^th intervals from the left represent a self-optimization interval for power control. When link 3 is a probing link and accesses a network including active links 1 and 2, it predicts . Because ^> , link 3 is automatically allowed to enter into the self-optimization interval for power control. After the self-optimization procedure for distributed power control, links 1, 2, and 3 obtain a feasible power distribution to achieve an objective that their respective working SINR level is greater than their respective target SINR. Then, after entering into the power optimization interval, the entire network reaches a critical point, wherein the SINRs of links 1, 2, 3, and 4 have reached their respective target SINRs, while the SINR level actually realized by link 5 is equal to ⁵ .

[0138] Through the self-organization and self-optimization method and apparatus for an ultra-dense network according to the embodiments of the present invention, during the self-organization interval for access control and the self-optimization interval for power control, the SINRs of the active links and the probing link have a fast converging speed; even in an extremity circumstance of - A Moreover, each link may independently suspend the iteration procedure of power update based on the convergence conditions of their respective SINRs.

[0139] The self-organization and self-optimization method and apparatus for an ultra-dense network according to the embodiments of the present invention adopts an autonomous process through the probing link intended to access the ultra-dense network and active links in the ultra-dense network, such that the probing link may decide whether to access the ultra-dense network based on the obtained maximum achievable SINR, which reduces power consumption while ensuring a higher unit spectrum efficiency, thereby efficiently utilizing the network resources. The present invention has the following technical features and advantages:

[0140] Firstly, the self-organization and self-optimization UDN according to the embodiments of the present invention offers a distributed channel-probing competence to exactly predict the maximal achievable SINR under multiple power constraint conditions. The self-optimization UDN weighs the capacity of frequency-spatial reuse competence in terms of the maximum achievable SINR. This method assures the Pareto optimality of frequency-spatial reuse in some sense. The forecast capability for the network critical point makes adaptive distribution of user rate possible, outperforming the traditional methods of only estimating the critical point.

[0141] Secondly, the self-organization and self-optimization UDN realizes on-line noninvasive probing and access. It allows the probing link to transmit a probing signal at an arbitrary constant power level while the active links still send data signals during the whole interval of channel probing. The probing behavior is not competitive and offensive, but mild and friendly. More precisely, the power of the probing signal can be set so small that the interference due to the probing link does not interrupt ongoing transmission of the active links. In addition, the self-optimization UDN offers an effective way to observe the upcoming state of expanded network rather than the current state of existing active network during the entire channel probing process.

[0142] Thirdly, the self-organization and self-optimization UDN is amenable to a large-scale autonomous network towards high degree of spatial reuse with lower computation cost and control overhead. The computation and control overhead of the self-optimization UDN is linearly increasing with respect to the total number of the communication links, but not exponentially. Remarkably, the distributed and parallel design without information exchange across links facilitates network scaling up in an autonomous manner.

[0143] Fourthly, the self-organization and self-optimization UDN ensures good backward compatibility with current wireless systems. The power updating procedure resembles the distributed power control mechanism that has been widely applied in the current wireless systems as a standardized technique. Also, the practical implementation of the power update procedure just involves local measurements for SINR, SNR, and normalized variance of noise that are familiar to the commercial communication system. All of these will ease the upgradation way from the existing commercial system to the self-organization and self-optimization UDN by merely modifying the rule of power updating.

[0144] In summary, the scheme according to the embodiments of the present invention offers a cognitive capability to forecast the global maximum of achievable SINR under multiple power constraints. It just executes a single iteration process and relies on nothing more than local measurements based on which the new link can autonomously and independently make an access decision with active link protection. Such a cognitive capability avoids prohibitive signaling overhead for signaling exchanging across links.

[0145] It should be noted that the present disclosure may be implemented in software or a combination of software and hardware; for example, it may be implemented by a dedicated integrated circuit (ASIC), a general-purpose computer, or any other similar hardware device. In an embodiment, the software program of the present disclosure may be executed by a processor so as to implement the above steps or functions. Likewise, the software program of the present disclosure (including relevant data structure) may be stored in a computer readable recording medium, for example, a RAM memory, a magnetic or optical driver, or a floppy disk, and similar devices. Besides, some steps of functions of the present disclosure may be implemented by hardware, for example, a circuit cooperating with the processor to execute various functions or steps.

[0146] To those skilled in the art, it is apparent that the present disclosure is not limited to the details of the above exemplary embodiments, and the present disclosure may be implemented with other forms without departing from the spirit or basic features of the present disclosure. Thus, in any way, the embodiments should be regarded as exemplary, not limitative; the scope of the present disclosure is limited by the appended claims, instead of the above depiction. Thus, all variations intended to fall into the meaning and scope of equivalent elements of the claims should be covered within the present disclosure. No reference signs in the claims should be regarded as limiting the involved claims. Besides, it is apparent that the term "comprise/comprising/include/including" does not exclude other units or steps, and singularity does not exclude plurality. A plurality of units or means stated in the apparatus claims may also be implemented by a single unit or means through software or hardware. Terms such as the first and the second are used to indicate names, but do not indicate any particular sequence.

Claims

1. A self-organization method for a probing link in an ultra-dense network, comprising:

transmitting, by a probing link, a probing signal at a fixed power;

when a locally measured Signal to Interference plus Noise Ratio SINR of an active link in the ultra-dense network converges to a constant, obtaining, by the probing link, a maximal achievable SINR of the probing link based on the locally measured current SINR, a Signal Noise Ratio SNR, and a currently achieved maximal value of power normalized, so as to cause the probing link to determine whether to access the ultra-dense network.

2. The self-organization method for a probing link according to claim 1, wherein the step of obtaining , by the probing link, a maximal achievable SINR of the probing link based on the locally measured current SINR, a Signal Noise Ratio SNR, and a currently achieved maximal value of power normalized comprises:

1 n=l,2,- - -,M +L

- +

SINR_L (t) , where ^l denotes the maximal achievable SINR of the probing link, SINR_L(t) d_enotes the locally measured current SINR value of the probing link, denotes the locally measured SNR value of the probing link, and ⁿ-^i>z>- - -^>M +L denotes the current power normalized maximal value.

3. A self-organization method for active links in an ultra-dense network, when a probing link transmits a probing signal at a fixed power, comprising:

updating, by each active link, a transmit power of a next time according to their respective target signal-to-interference plus noise ratio SINR, current SINR as locally measured, normalized noise power value as locally measured, current transmit power value, and current power normalized maximal value;

iteratively updating, by each active link according the updating the transmit power of the next time, its transmit power with time, till the local measured SINR value of the active link is converged to a constant.

4. The self-organization method for active links according to claim 3, wherein the step of

updating, by each active link, a transmit power of a next time according to their respective target signal-to-interference plus noise ratio SINR, current SINR as locally measured, normalized noise power value as locally measured, current transmit power value, and current power normalized maximal value comprises: updating the transmit power at the next time to

βι βι^ηι

P_l (t + 1) = - ^■p, (t) +

SINR^t) G_u n=l,2,- - -,M+L

, where ^l denotes a target SINR of active link /, ^^^i d_enot_es a locally measured current SINR value of active /, ^ denotes a transmit

___L

power of the current active link /; ¹¹ denotes a locally measured normalized noise power value of the ITl^tlX^. \ n, normal

active l iinnkk //;; M "^{=1 Z} -^"" +L denotes the current power normalized maximal value.

5. A self-organization and self-optimization method for an ultra-dense network, comprising:

transmitting, by a probing link, a probing signal at a fixed power;

iteratively updating, by each active link according the updating the transmit power of the next time, its transmit power with time, till the local measured SINR value of the active link is converged to a constant; then obtaining, by the probing link, a maximal achievable SINR of the probing ink based on the current SINR as locally measured, the Signal Noise Ratio SNR, and the current power normalized maximal value; when the maximal achievable SINR is greater than or equal to a target SINR of the probing link, the probing link as an active link accessing the ultra-dense network; and

updating, by the probing link and the active link, their respective transmit powers according to their own target SINRs, current SINRs as locally measured, current transmit power values, and current power normalized maximal values, till each working SINR of the probing link and the active link is greater than their respective target SINRs.

6. The self-organization and self-optimization method according to claim 5, further comprising:

determining and broadcasting the current power normalized maximal value, the current power normalized maximal value ⁿ-^i>z>- - -^>M +L includes: a largest value among the normalized transmit

P (t)

power M+i, normal L-l) of each active link in the ultra-dense network, the normalized transmit

P (t) P (t) power M+L,normai _Qf _tne p_robj_ng link, and the normalized outward interference power ^m'^normal

P M +1, normal ( ^vt) ' = p - - ^\

(m=l, 2 ... M) of each external link in the ultra-dense network; wherein ^M+l , ¹ p

denotes the transmit power of the current active link /, ^{M +l} denotes a maximal allowable transmit power

P p

of the active link I; wherein P_{M+L normal} (t) =— , P_L denotes the fixed power, ^{M +L} denotes the

maximal allowable transmit power of the probing link; wherein P_m V i=i where denotes an acceptable interference power upper limit of the external m, ^WmJ denotes a channel gain from a transmitter of the active link / to the receiver of the external link m, ^{m i} denotes a channel gain from the transmitter of the probing link L to the receiver of the external link m.

7. A self-organization apparatus for a probing link in an ultra-dense network, comprising:

a transmitter of a probing link, for transmitting a probing signal at a fixed power;

a receiver of the probing link, for, when a locally measured Signal to Interference plus Noise Ratio of an active link in the ultra-dense network converges to a constant, obtaining a maximal achievable SINR of the probing link based on the locally measured current SINR, a Signal Noise Ratio SNR, and a currently achieved maximal value of power normalized, so as to cause the probing link to determine whether to access the ultra-dense network.

8. The self-organization method for a probing link according to claim 7, wherein a receiver of the probing link is specifically for determining

1 n=l,2,- - -,M +L

- +

SINR_L (t) , where ^l denotes the maximal achievable SINR of the probing link, SINR_L(t) d_enotes the locally measured current SINR value of the probing link, denotes the locally measured SNR value of the probing link, and

denotes the current power normalized maximal value.

9. A self-organization apparatus for an active link in an ultra-dense network, comprising:

a power updater for self-organization for, when a probing link transmits a probing signal at a fixed power, updating, by each active link, a transmit power of a next time according to their respective target signal-to-interference plus noise ratio SINR, current SINR as locally measured, normalized noise power value as locally measured, current transmit power value, and current power normalized maximal value; and iteratively updating, by each active link according the updating the transmit power of the next time, its transmit power with time, till the local measured SINR value of the active link is converged to a constant.

10. The self-organization apparatus for active links according to claim 9, wherein the power updater for self-organization is specifically for updating a transmit power of the next time to

βι βι^ηι

P_l (t + 1) = - ^■p, (t) +

SINR^t) G_u n=l,2,- - -,M+L

where ^l denotes a target SINR of active link /, ^^^i d_enot_es a locally measured current SINR value of active /, ^ denotes a transmit

___L

power of the current active link /; ¹¹ denotes a locally measured normalized noise power value of the active l iinnkk //;; ""⁼¹·'²·'- ^{' " ++LL} denotes the current power normalized maximal value.

11. A self-organization and self-optimization apparatus for an ultra-dense network, comprising: a transmitter of a probing link, for transmitting a probing signal at a fixed power;

a power updater for self-organization, for, when the transmitter of the probing link transmits the probing signal, updating, by each active link, a transmit power of a next time according to their respective target signal-to-interference plus noise ratio SINR, current SINR as locally measured, normalized noise power value as locally measured, current transmit power value, and current power normalized maximal value; and iteratively updating, by each active link according the updating the transmit power of the next time, its transmit power with time, till the local measured SINR value of the active link is converged to a constant; then triggering a receiver of the probing link;

the receiver of the probing link, for obtaining a maximal achievable SINR of the probing ink based on the current SINR as locally measured, the Signal Noise Ratio SNR, and the current power normalized maximal value;

an access controller of the probing link, for, when the maximal achievable SINR is greater than or equal to a target SINR of the probing link, accessing the probing link as an active link to the ultra-dense network; and

a power updater for optimization, for, when the access controller of the probing link controls the probing link as an active link to access to the ultra-dense network, updating, by the probing link and the active link, their respective transmit powers according to their own target SINRs, current SINRs as locally measured, current transmit power values, and current power normalized maximal values, till each working SINR of the probing link and the active link is greater than their respective target SINRs.

12. The self-organization and self-optimization apparatus according to claim 11, further comprising:

a power normalized maximal value broadcaster for determining and broadcasting the current power normalized maximal value, the current power normalized maximal value ⁿ-^i>z>- - -^>M +L includes:

P (t)

a largest value among the normalized transmit power M+I, normal _t„ L-1) of each active link in the

P (t)

P M+l .normal ( Vt) ' = ^^(t)

wherein PM^M+⁺I^l , Pi ' (t) denotes the transmit power of the current active link /, ^{M +l} denotes a maximal allowable transmit power of the active link I; wherein , P_L

p

_t where ^m denotes an acceptable interference power upper limit of the external m, denotes a channel gain from a transmitter of the active link / to the receiver of the external link m, ^{m i} denotes a channel gain from the transmitter of the probing link L to the receiver of the external link m.