CN104581867A - Data distribution method with fairness and energy-saving effect by means of D2D cooperative communication at equal data block transmission time - Google Patents

Abstract

A data distribution method with fairness and an energy-saving effect by means of D2D cooperative communication at equal data block transmission time comprises the following steps that first, the distribution of a data block is accomplished at the equal data block transmission time in order to solve a problem, meanwhile compared with the way that each user downloads the data block from a base station separately, the energy-saving effect is achieved, the fairness of the users is also taken into account, that is to say, the data block transmission time is evenly distributed to each user meeting relay conditions, and a method is designed to obtain the transmission time and the transmission rate of the data block; second, limiting conditions which need to be considered in the data distribution process are determined, the data distribution method on the condition that the transmission time and the transmission rate of the data block are given is designed for the limiting conditions, and the distribution of the data block is accomplished finally. According to the data distribution method with the energy-saving effect, fairness principle is taken into account, and the control over the data block transmission time and the control over the corresponding user relay selection and relay time are achieved.

Description

The data distributing method with fairness and energy-saving effect of D2D collaboration communication is utilized under the transmission of data blocks time such as a kind of

Technical field

The present invention relates in the D2D communications field, under the transmission of data blocks time such as especially a kind of, utilize the data distributing method with fairness and energy-saving effect of D2D collaboration communication.

Background technology

In recent years, along with the explosive growth of Mobile data traffic demand, limited Resource Allocation in Networks also faces enormous challenge, in this context, the D2D communication pattern of multiplexing legacy network resource can more and more receive the concern of people.Meanwhile, along with popularizing of network, social networks has become the indispensable a kind of manner of intercourse of people, and in social networks, people can realize sharing the data block resource comprising various picture, film etc.And the people being in same place (such as office building office, classroom etc.) overlap significantly for the hobby of social network content has, utilizing D2D communication mode to realize distributing the collaboration type of the data block that people have joint demand to like, is a kind of very novel application model.This pattern is fitted social demand instantly more, with stronger purpose, and performance more efficiently.Therefore, realizes distributing the collaboration type of the data block of user's joint demand while how research takes into account user fairness principle, while be respectively significantly since the mode of base station downloading data block reaches energy-conservation effect compared to user.

Summary of the invention

Lacking that well to apply experiences, energy consumption comparatively large and lack the deficiency of to a certain degree fairness measure to overcome traditional D2D communication pattern, under the invention provides the transmission of data blocks time such as a kind ofly have that applications well experience, energy consumption are less, fairness is good, utilizing the data distributing method with fairness and energy-saving effect of D2D collaboration communication.

The technical solution adopted for the present invention to solve the technical problems is:

Etc. utilize the data distributing method with fairness and energy-saving effect of D2D collaboration communication under the transmission of data blocks time, described data distributing method comprises the following steps:

(1) based in the communication network of D2D, have individual user, N is total number of users, individual data block, K is total data block number, and wherein, the demand customer group of data block k is Ω ^k, the transmission time of data block k is x ^k, the size of data block k is L ^k, the unit transmission time of data block k is v ^k, the number of dividing equally of data block is S, and the set of data blocks required for user i is combined into U _i, base station needs the transmission completed in single timeslice T K data block, by the transmission time x of data block k before Data dissemination ^kbeing divided into every part of transmission time of S part is v ^k, meet and have the trunk subscriber of energy-saving effect condition to judge whether in order to meet transmission v ^ktime, until user's utilisable energy exhausts or do not meet transmission condition, finally determine that the user being chosen as relaying to the relaying time of data block k is after base station starts data transmission, the user being chosen as relaying exists receive in time and be in same customer group Ω from being broadcast to immediately while base station data block k with this trunk subscriber ^kother users, finally, if the transmission time x of data block k ^kresidue is being still had, namely after all selectable user relayings then transmission time directly user's broadcast transmission data are completed by base station; For this problem, described transmission of data blocks time x ^kspecifically obtained by following steps:

Step 1.1: base station is all equal to the transmission time of K data block in single timeslice T, therefore, for the transmission time x of data block k ^khave, wherein, x ^krepresent the transmission time of data block k, k represents data block set in a kth data block, K represents total number of data block, and T represents single timeslice length;

Step 1.2: for data block k, according to the transmission time x that step 1.1 obtains ^k, its transmission rate R ^khave, wherein, R ^krepresent the transmission rate of data block k, L ^krepresent the size of data block k;

(2) method Gen Ju (1), exists for the described user being chosen as relaying receive in time and be in same customer group Ω from being broadcast to immediately while base station data block k with this trunk subscriber ^kthe process of he user interior, consider the restrictive condition realizing this process based on D2D collaboration communication, described restrictive condition comprises following content:

User i is as the trunk subscriber time of data block k the transmission time x of data block k can not be exceeded ^k, that is:

$\underset{i\∈{\mathrm{\Ω}}^k}{\mathrm{\Σ}}{z}_i^k\≤x^k\∀k$

The energy of user i in the relay forwarding and reception desired data process of complete paired data block k can not exceed its utilisable energy wherein the data block k of user i required for it carries out forwarding power demand and is $\frac{n}{{\min }_{i\∈{\mathrm{\Ω}}^k}\left\{g_{\mathrm{ij}}\right\}}(2^{R^k}-1)+q_i,$ Corresponding energy consumption is $(\frac{n}{{\min }_{i\∈{\mathrm{\Ω}}^k}\left\{g_{\mathrm{ij}}\right\}}(2^{R^k}-1)+q_i)z_i^k;$ User i for receiving received power needed for data block k is corresponding energy consumption is therefore namely:

$\underset{k\∈U_i}{\mathrm{\Σ}}(\frac{n}{\underset{i\∈{\mathrm{\Ω}}^k}{\min }\left\{g_{\mathrm{ij}}\right\}}(2^{R^k}-1)+q_i)z_i^k+\underset{k\∈U_i}{\mathrm{\Σ}}{h}_i^k{x}^k\≤E_i^{\max }\∀i$

User i transmitted power when the trunk subscriber as data block k can not exceed its maximum transmit power otherwise user i can not be selected as relaying, that is:

$z_i^k\≤x^k\·I(\frac{n}{\underset{i\∈{\mathrm{\Ω}}^k}{\min }\left\{g_{\mathrm{ij}}\right\}}(2^{R^k}-1)+q_i\≤P_i^{\max })\∀i,k$

Wherein, function

In above-mentioned restrictive condition, each parameter is defined as follows:

I: user i;

Q _i: user i is sending circuit power consumption during data block;

R ^k: the transmission rate of data block k;

X ^k: the transmission time of data block k;

N: channel background noise;

G _ij: the channel gain between user i and user j;

user i receives the received power in data block k process;

user i is chosen as the transmitting time for data block k after relaying;

user i maximum available energy;

user i maximum transmit power;

Ω ^k: there is the user of demand to gather for data block k;

U _i: the data block set of user i demand;

According to described restrictive condition, under the Bulk transport time of method data-oriented described in (1), select user as the fairness also will taken into account while relaying each user in the customer group of data block k demand, energy consumption is as much as possible all assigned in the user meeting relay condition go, namely under the prerequisite reaching energy-saving effect, selection user as much as possible as relaying to belonging to set omega ^kother users carry out the distribution of data block k, step comprises:

Step 2.1: make tR ^k=x ^k, w=0, wherein, tR ^krepresent that data block k completes the residue transmission time of transmission, ER _irepresent the residue utilisable energy of user i, w represents θ in i, the corresponding ER of k _i=0, tR ^k=0 or user i not meet transmitted power number;

Step 2.2: considering transmission of data blocks speed and comprising base station to user, user under user's channel circumstance factor, defined variable calculate and set omega is belonged to for all data block k correspondences ^kunder interior all users

Step 2.3: all by what calculate in step 2.2 sort from small to large, specific as follows:

Wherein, represent arrange from small to large individual, wherein, θ represents number;

Step 2.4: by data block k transmission time x ^kbe divided into S part, even wherein, v ^krepresent the unit transmission timeslice of data block k, S represents transmission of data blocks time x ^kdivide equally number;

Step 2.5: if θ=0, then skip to step 2.8; Otherwise make l=1, wherein, l represents current sequence number;

Step 2.6: step 2.3 is obtained according to in i, k obtains corresponding ER _iand tR ^kif judge ER _i=0, tR ^k=0, then w=w+1 skips to step 2.7; Otherwise judge simultaneously ${\mathrm{ER}}_i-(\frac{n}{{\min }_{i\∈{\mathrm{\Ω}}^k}\left\{g_{\mathrm{ij}}\right\}}(2^{R^k}-1)+q_i)v^k\≥0,$ If so, then $z_i^k=z_i^k+v^k,{\mathrm{ER}}_i={\mathrm{ER}}_i-$ tR ^k=tR ^k-v ^k, if not, then w=w+1 skips to step 2.7;

Step 2.7: if w=is θ, then skip to step 2.8, otherwise make l=l+1, if l> is θ, then makes l=1, and w=0 also skips to step 2.6, otherwise jumps directly to step 2.6;

Step 2.8: for data block k, if still have transmission time residue, then remain the transmission time directly broadcasted by base station;

Step 2.9: export: user i is to the transmission time of data block k

Technical conceive of the present invention is: first, in conjunction with D2D communication and social networks advantages characteristic separately, waiting the distribution of complete paired data block under the transmission of data blocks time, reach energy-conservation effect compared to each mode since base station downloading data block of each user simultaneously, also take into account the fairness of user on this basis to a certain extent, all give each user meeting relay condition as much as possible by the transmission of data blocks time.For this problem, method for designing obtains the transmission time of data block and the transmission rate of data block.Secondly, determine the restrictive condition needing to consider in data dissemination process, for the data distributing method of restrictive condition design under data-oriented Bulk transport time and transmission rate.Namely realize taking into account the Data dissemination by transmission of data blocks time controling and corresponding user's relay selection and relaying time control realization of fair principle under D2D collaboration communication, simultaneously compared to user respectively since base station downloading data block mode reaches energy-conservation effect.

Beneficial effect of the present invention is mainly manifested in: 1, for base station, the advantage communicated by utilizing D2D, and what realize legacy network resource is multiplexing, can reduce the traffic load of base station well; 2, for user, by with the communication mode of the cooperation among users based on D2D, while obtaining data resource, also reach the benefit of saving flow rate, based on the principle of fairness, for trunk subscriber, the energy penalty that relay processes is paid also is reduced as much as possible; 3, for whole system, in rational user collaboration mode, the energy consumption object controlling whole data block distribution procedure is effectively reached; 4, society demand of combining closely focus, ingeniously utilizes social networks characteristic, realizes the efficiency utilization of data resource.

Accompanying drawing explanation

Fig. 1 is the data block dissemination system schematic diagram based on D2D collaboration communication.

Embodiment

Below in conjunction with accompanying drawing, the present invention is described in further detail.

With reference to Fig. 1, the data distributing method with fairness and energy-saving effect of D2D collaboration communication is utilized under the transmission of data blocks time such as a kind of, carry out the method can meet each user to data block demand under to take into account between trunk subscriber while fair principle, complete the distribution of data block based on D2D collaboration communication, reach energy-conservation effect compared to each mode since base station downloading data block of each user simultaneously.The present invention is based on the data distribution systems (as shown in Figure 1) of D2D collaboration communication.In the data distribution systems based on D2D collaboration communication, D2D user with common interest demand in social networks for background, collaboration communication is carried out by D2D mode, devise and take into account fair principle and with the data point method of energy-saving effect, effectively improve the utilance of resource, reduce the load of base station.For the data distribution systems based on D2D collaboration communication, propose to consider on fair principle basis to pass through transmission of data blocks time controling and to select user as Data dissemination relaying and the mode as relaying time thereof, complete the distribution to required user of data block, and with energy-saving effect, described data distributing method comprises the following steps:

(1) based in the communication network of D2D, have individual user, N is total number of users, individual data block, K is total data block number, and wherein, the demand customer group of data block k is Ω ^k, the transmission time of data block k is x ^k, the size of data block k is L ^k, the unit transmission time of data block k is v ^k, the number of dividing equally of data block is S, and the set of data blocks required for user i is combined into U _i, base station needs the transmission completed in single timeslice T K data block, by the transmission time x of data block k before Data dissemination ^kbeing divided into every part of transmission time of S part is v ^k, meet and have the trunk subscriber of energy-saving effect condition to judge whether in order to meet transmission v ^ktime, until user's utilisable energy exhausts or do not meet transmission condition, finally determine that the user being chosen as relaying to the relaying time of data block k is after base station starts data transmission, the user being chosen as relaying exists receive in time and be in same customer group Ω from being broadcast to immediately while base station data block k with this trunk subscriber ^kother users, finally, if the transmission time x of data block k ^kresidue is being still had, namely after all selectable user relayings then transmission time directly user's broadcast transmission data are completed by base station; For this problem, described transmission of data blocks time x ^kspecifically obtained by following steps:

Step 1.1: base station is all equal to the transmission time of K data block in single timeslice T, therefore, for the transmission time x of data block k ^khave, wherein, x ^krepresent the transmission time of data block k, k represents data block set in a kth data block, K represents total number of data block, and T represents single timeslice length;

Step 1.2: for data block k, according to the transmission time x that step 1.1 obtains ^k, its transmission rate R ^khave, wherein, R ^krepresent the transmission rate of data block k, L ^krepresent the size of data block k;

(2) method Gen Ju (1), exists for the described user being chosen as relaying receive in time and be in same customer group Ω from being broadcast to immediately while base station data block k with this trunk subscriber ^kthe process of he user interior, consider the restrictive condition realizing this process based on D2D collaboration communication, described restrictive condition comprises following content:

User i is as the trunk subscriber time of data block k the transmission time x of data block k can not be exceeded ^k, that is:

$\underset{i\∈{\mathrm{\Ω}}^k}{\mathrm{\Σ}}{z}_i^k\≤x^k\∀k$

The energy of user i in the relay forwarding and reception desired data process of complete paired data block k can not exceed its utilisable energy wherein the data block k of user i required for it carries out forwarding power demand and is $\frac{n}{{\min }_{i\∈{\mathrm{\Ω}}^k}\left\{g_{\mathrm{ij}}\right\}}(2^{R^k}-1)+q_i,$ Corresponding energy consumption is $(\frac{n}{{\min }_{i\∈{\mathrm{\Ω}}^k}\left\{g_{\mathrm{ij}}\right\}}(2^{R^k}-1)+q_i)z_i^k;$ User i for receiving received power needed for data block k is corresponding energy consumption is therefore namely:

$\underset{k\∈U_i}{\mathrm{\Σ}}(\frac{n}{\underset{i\∈{\mathrm{\Ω}}^k}{\min }\left\{g_{\mathrm{ij}}\right\}}(2^{R^k}-1)+q_i)z_i^k+\underset{k\∈U_i}{\mathrm{\Σ}}{h}_i^k{x}^k\≤E_i^{\max }\∀i$

User i transmitted power when the trunk subscriber as data block k can not exceed its maximum transmit power otherwise user i can not be selected as relaying, that is:

$z_i^k\≤x^k\·I(\frac{n}{\underset{i\∈{\mathrm{\Ω}}^k}{\min }\left\{g_{\mathrm{ij}}\right\}}(2^{R^k}-1)+q_i\≤P_i^{\max })\∀i,k$

Wherein, function

In above-mentioned restrictive condition, each parameter is defined as follows:

I: user i;

Q _i: user i is sending circuit power consumption during data block;

R ^k: the transmission rate of data block k;

X ^k: the transmission time of data block k;

N: channel background noise;

G _ij: the channel gain between user i and user j;

user i receives the received power in data block k process;

user i is chosen as the transmitting time for data block k after relaying;

user i maximum available energy;

user i maximum transmit power;

Ω ^k: there is the user of demand to gather for data block k;

U _i: the data block set of user i demand;

According to described restrictive condition, under the Bulk transport time of method data-oriented described in (1), select user as the fairness also will taken into account while relaying each user in the customer group of data block k demand, energy consumption is as much as possible all assigned in the user meeting relay condition go, namely under the prerequisite reaching energy-saving effect, selection user as much as possible as relaying to belonging to set omega ^kother users carry out the distribution of data block k, step comprises:

Step 2.1: make tR ^k=x ^k, w=0, wherein, tR ^krepresent that data block k completes the residue transmission time of transmission, ER _irepresent the residue utilisable energy of user i, w represents θ in i, the corresponding ER of k _i=0, tR ^k=0 or user i not meet transmitted power number;

Step 2.2: considering transmission of data blocks speed and comprising base station to user, user under user's channel circumstance factor, defined variable calculate and set omega is belonged to for all data block k correspondences ^kunder interior all users

Step 2.3: all by what calculate in step 2.2 sort from small to large, specific as follows:

Wherein, represent arrange from small to large individual, wherein, θ represents number;

Step 2.4: by data block k transmission time x ^kbe divided into S part, even wherein, v ^krepresent the unit transmission timeslice of data block k, S represents transmission of data blocks time x ^kdivide equally number;

Step 2.5: if θ=0, then skip to step 2.8; Otherwise make l=1, wherein, l represents current sequence number;

Step 2.6: step 2.3 is obtained according to in i, k obtains corresponding ER _iand tR ^kif judge ER _i=0, tR ^k=0, then w=w+1 skips to step 2.7; Otherwise judge simultaneously ${\mathrm{ER}}_i-(\frac{n}{{\min }_{i\∈{\mathrm{\Ω}}^k}\left\{g_{\mathrm{ij}}\right\}}(2^{R^k}-1)+q_i)v^k\≥0,$ If so, then $z_i^k=z_i^k+v^k,{\mathrm{ER}}_i={\mathrm{ER}}_i-$ tR ^k=tR ^k-v ^k, if not, then w=w+1 skips to step 2.7;

Step 2.7: if w=is θ, then skip to step 2.8, otherwise make l=l+1, if l> is θ, then makes l=1, and w=0 also skips to step 2.6, otherwise jumps directly to step 2.6;

Step 2.8: for data block k, if still have transmission time residue, then remain the transmission time directly broadcasted by base station;

Step 2.9: export: user i is to the transmission time of data block k

The present embodiment is conceived to society focus demand, the ingenious characteristic advantage in conjunction with social networks, based on D2D collaboration communication, to take into account between trunk subscriber while fair principle, realize Data dissemination by the mode of transmission of data blocks time controling and corresponding user's relay selection and relaying time control, finally reach energy-conservation effect compared to each mode since base station downloading data block of each user.Our work can make Virtual network operator obtain more interests, serve more user, also make user reach the object obtaining and save corresponding discharge rate while data resource, effectively improve the utilance of data resource, finally make Virtual network operator and user can doulbe-sides' victory.

Claims (1)

1. etc. utilize the data distributing method with fairness and energy-saving effect of D2D collaboration communication under the transmission of data blocks time, it is characterized in that: described data distributing method comprises the following steps:

(1) based in the communication network of D2D, have individual user, N is total number of users, individual data block, K is total data block number, and wherein, the demand customer group of data block k is Ω ^k, the transmission time of data block k is x ^k, the size of data block k is L ^k, the unit transmission time of data block k is v ^k, the number of dividing equally of data block is S, and the set of data blocks required for user i is combined into U _i, base station needs the transmission completed in single timeslice T K data block, by the transmission time x of data block k before Data dissemination ^kbeing divided into every part of transmission time of S part is v ^k, meet and have the trunk subscriber of energy-saving effect condition to judge whether in order to meet transmission v ^ktime, until user's utilisable energy exhausts or do not meet transmission condition, finally determine that the user being chosen as relaying to the relaying time of data block k is after base station starts data transmission, the user being chosen as relaying exists receive in time and be in same customer group Ω from being broadcast to immediately while base station data block k with this trunk subscriber ^kother users, finally, if the transmission time x of data block k ^kresidue is being still had, namely after all selectable user relayings then transmission time directly user's broadcast transmission data are completed by base station; For this problem, described transmission of data blocks time x ^kspecifically obtained by following steps:

Step 1.1: base station is all equal to the transmission time of K data block in single timeslice T, therefore, for the transmission time x of data block k ^khave, wherein, x ^krepresent the transmission time of data block k, k represents data block set in a kth data block, K represents total number of data block, and T represents single timeslice length;

Step 1.2: for data block k, according to the transmission time x that step 1.1 obtains ^k, its transmission rate R ^khave, wherein, R ^krepresent the transmission rate of data block k, L ^krepresent the size of data block k;

(2) method Gen Ju (1), exists for the described user being chosen as relaying receive in time and be in same customer group Ω from being broadcast to immediately while base station data block k with this trunk subscriber ^kthe process of he user interior, consider the restrictive condition realizing this process based on D2D collaboration communication, described restrictive condition comprises following content:

User i is as the trunk subscriber time of data block k the transmission time x of data block k can not be exceeded ^k, that is:

$\underset{i\∈{\mathrm{\Ω}}^k}{\mathrm{\Σ}}{z}_i^k\≤x^k\∀k$

The energy of user i in the relay forwarding and reception desired data process of complete paired data block k can not exceed its utilisable energy wherein the data block k of user i required for it carries out forwarding power demand and is corresponding energy consumption is user i for receiving received power needed for data block k is corresponding energy consumption is therefore namely:

$\underset{k\∈U_i}{\mathrm{\Σ}}(\frac{n}{\underset{i\∈{\mathrm{\Ω}}^k}{\min }\left\{g_{\mathrm{ij}}\right\}}(2^{R^k}-1)+q_i)z_i^k+\underset{k\∈U_i}{\mathrm{\Σ}}{h}_i^k{x}^k\≤E_i^{\max }\∀i$

User i transmitted power when the trunk subscriber as data block k can not exceed its maximum transmit power otherwise user i can not be selected as relaying, that is:

$z_i^k\≤x^k\·I(\frac{n}{\underset{i\∈{\mathrm{\Ω}}^k}{\min }\left\{g_{\mathrm{ij}}\right\}}(2^{R^k}-1)+q_i\≤p_i^{\max })\∀i,k$

Wherein, function

In above-mentioned restrictive condition, each parameter is defined as follows:

I: user i;

Q _i: user i is sending circuit power consumption during data block;

R ^k: the transmission rate of data block k;

X ^k: the transmission time of data block k;

N: channel background noise;

G _ij: the channel gain between user i and user j;

user i receives the received power in data block k process;

user i is chosen as the transmitting time for data block k after relaying;

user i maximum available energy;

user i maximum transmit power;

Ω ^k: there is the user of demand to gather for data block k;

U _i: the data block set of user i demand;

According to described restrictive condition, under the Bulk transport time of method data-oriented described in (1), select user as the fairness also will taken into account while relaying each user in the customer group of data block k demand, energy consumption is as much as possible all assigned in the user meeting relay condition go, namely under the prerequisite reaching energy-saving effect, selection user as much as possible as relaying to belonging to set omega ^kother users carry out the distribution of data block k, step comprises:

Step 2.1: make tR ^k=x ^k, ${\mathrm{ER}}_i=E_i^{\max }-{\mathrm{\Σ}}_{k\∈U_i}{h}_i^k{x}^k,z_i^k=0$ W=0, wherein, tR ^krepresent that data block k completes the residue transmission time of transmission, ER _irepresent the residue utilisable energy of user i, w represents θ in i, the corresponding ER of k _i=0, tR ^k=0 or user i not meet transmitted power number;

Step 2.2: considering transmission of data blocks speed and comprising base station to user, user under user's channel circumstance factor, defined variable calculate and set omega is belonged to for all data block k correspondences ^kunder interior all users

Step 2.3: all by what calculate in step 2.2 sort from small to large, specific as follows:

Wherein, represent arrange from small to large individual, wherein, θ represents number;

Step 2.4: by data block k transmission time x ^kbe divided into S part, even wherein, v ^krepresent the unit transmission timeslice of data block k, S represents transmission of data blocks time x ^kdivide equally number;

Step 2.5: if θ=0, then skip to step 2.8; Otherwise make l=1, wherein, l represents current sequence number;

Step 2.6: step 2.3 is obtained according to in i, k obtains corresponding ERi and tRk, if judge ERi=0, tRk=0, then w=w+1 skips to step 2.7; Otherwise judge eR simultaneously _i- $(\frac{n}{{\min }_{i\∈{\mathrm{\Ω}}^k}\left\{g_{\mathrm{ij}}\right\}}(2^{R^k}-1)+q_i)v^k\≥0,$ If so, then $z_i^k=z_i^k+v^k,$ ER _i＝ER _i- $(\frac{n}{{\min }_{i\∈{\mathrm{\Ω}}^k}\left\{g_{\mathrm{ij}}\right\}}(2^{R^k}-1)+q_i)v^k,$ ${\mathrm{tR}}^k={\mathrm{tR}}^k-v^k,$ If not, then w=w+1 skips to step 2.7;

Step 2.7: if w=is θ, then skip to step 2.8, otherwise make l=l+1, if l> is θ, then makes l=1, and w=0 also skips to step 2.6, otherwise jumps directly to step 2.6;

Step 2.8: for data block k, if still have transmission time residue, then remain the transmission time directly broadcasted by base station;

Step 2.9: export: user i is to the transmission time of data block k