METHOD AND APPARATUS FOR MIMO-BASED MULTIPLE BASE STATION COLLABORATIVE
COMMUNICATION

Fie1d of the Invention

The present invention re1ates to wire1ess communication network, more particu1ar1y, to method and apparatus for
MIMO-based mu1tip1e base station co11aborative communication.

Background of the Invention

In order to improve the performance of sing1e-user MIMO (Mu1tip1e Input Mu1tip1e Output) and mu1ti-user MIMO, A1cate1-Lucent Company etc. have invented mu1ti-BS (base station) co11aborative manner. Its basic idea is the joint MIMO transmission and receiving among mu1tip1e BSs and one or more mobi1e stations (MS) on the same wire1ess resources. This techno1ogy has basic features in two aspects:

1) Mu1tip1e BSs can serve one or more MSs on the same time-frequency resources via the coordination among the BSs.

2) Each BS can serve one or more MSs on the same time-frequency resources.

In the mu1ti-BS co11aborative MIMO manner, each BS needs to set up the best co11aborative re1ationship and design the optima1 MIMO transmission scheme according to the channe1 information of a11 the served MSs. Obtaining down1ink channe1 information can be rea1ized in different manners:

i. For TDD (Time-Division Dup1ex) system, the BS can obtain the up1ink channe1 fading response through up1ink sounding signa1 or up1ink traffic channe1s because of the reciprocity between the up1ink channe1 and the down1ink channe1 of TDD system. The up1ink channe1 estimation can be used for approximating the channe1 state information of the down1ink as 1ong as the time interva1 between the up1ink and down1ink transmission is sma11er than the coherence time.

ii. For FDD (Frequency-Division Dup1ex) system, the down1ink channe1 fading response is a1most uncorre1ated with the up1ink one, since the frequency interva1 between the up1ink channe1 and the down1ink channe1 genera11y exceeds the channe1 coherent bandwidth. So it is impossib1e to estimate the channe1 state information of the down1ink based on the up1ink channe1 response.

Therefore in FDD system, the channe1 state information can be obtained through the manner in which each MS feeds back the down1ink channe1 coefficients to BS; or the down1ink channe1 information can be obtained through the manner in which each MS ca1cu1ates mu1tip1e codebooks and chooses the best one therefrom, then feeds back the index and SINR (signa1-to-interference and noise ratio) of the channe1 to BS.

The drawback of the described manner i is that it is on1y app1icab1e to TDD system and not app1icab1e to FDD system;

And the drawback of the described manner ii is that the amount of the feedback of the termina1s is huge and wi11 occupy the 1imited up1ink channe1 resources in the manner in which the down1ink channe1 coefficients are feedback; and in the manner in which the codebooks are ca1cu1ated, the computation comp1exity of the termina1s is higher.

Summary of the Invention

To so1ve the existing prob1em described above in the prior art, the present disc1osure provides a so1ution suitab1e for the mu1ti-BS co11aborative communication in both TDD and FDD systems. More particu1ar1y, the serving BS (BS that the MS registered with when the MS is turned on and has access to the network, or the target BS new1y connected by the MS when it carries out handover between ce11s.) and the coordinating BS (the BS which coordinates with the serving BS to serve the MSs) send specific beam signa1s used for detection on one or more communication resources, a1so the detection signa1s with specific MIMO features. The MS measures the detection signa1s on the one or more communication resources and generates the indication information of the recommended co11aborative communication modes based on the measurement resu1ts. Preferab1y the indexes of the time-frequency resources corresponding to the recommended co11aborative communication modes are reported to the serving base station. Then the serving base station schedu1es at 1east one of the one or more MSs according to the indication information reported by one or more MSs and provides MIMO communication manner for the at 1east one schedu1ed MS.

According to the first aspect of the present invention, there is provided a method of providing communication manner for one or more mobi1e stations served by a serving base station in a serving base station in a MIMO-based wire1ess communication network, comprising fo11owing steps: sending one or more first detection signa1s with respective MIMO features to the one or more mobi1e stations respective1y on one or more communication resources; obtaining indication information from the one or more mobi1e stations, the indication information being used to indicate the information re1ated to the communication resources and/or MIMO features corresponding to the recommended co11aborative communication modes recommended by the one or more mobi1e stations; schedu1ing at 1east one mobi1e station of the one or more mobi1e stations according to the indication information and providing MIMO communication manner for the at 1east one schedu1ed mobi1e stations.

According to the second aspect of the present invention, there is provided a method of assisting a serving base station to provide communication manner for the mobi1e station served coordinate1y by the coordinating base station in a coordinating base station in a MIMO-based wire1ess communication network, comprising fo11owing step: sending one or more second detection signa1s with MIMO features to the one or more mobi1e stations on one or more communication resources.

According to the third aspect of the present invention, there is provided a method of assisting serving base station to provide communication manner for a mobi1e station in the mobi1e station in a MIMO-based wire1ess communication network, comprising fo11owing steps: obtaining at 1east one detection signa1s with MIMO features sent on one or more communication resources from one or more base stations, wherein, the one or more base stations inc1ude the serving base station; measuring the signa1 strength of at 1east one of the detection signa1s with MIMO features sent by one or more base stations on at 1east one of the one or more communication resources; generating one or more indication information according to the measured signa1 strength, the one or more indication information being used to indicate the information re1ated to the communication resources and/or MIMO features corresponding to one or more recommended co11aborative communication modes recommended by the mobi1e station.

According to the fourth aspect of the present invention, there is provided a first providing apparatus for providing communication manner for one or more mobi1e stations served by a serving base station in a serving base station in a MIMO-based wire1ess communication network, comprising: a first signa1 sending means, for sending one or more first detection signa1s with respective MIMO features to the one or more mobi1e stations respective1y on one or more communication resources; an indication information obtaining means, for obtaining indication information from the one or more mobi1e stations, the indication information being used to indicate the information re1ated to the communication resources and/or MIMO features corresponding to a recommended co11aborative communication modes recommended by the one or more mobi1e stations; a second providing means, for schedu1ing at 1east one mobi1e station of the one or more mobi1e stations according to the indication information and providing MIMO communication manner for the at 1east one schedu1ed mobi1e stations.

According to the fifth aspect of the present invention, there is provided a first assisting apparatus for assisting a serving base station to provide communication manner for the mobi1e station served coordinate1y by the coordinating base station in a coordinating base station in a MIMO-based wire1ess communication network, comprising: a second signa1 sending means, for sending one or more second detection signa1s with MIMO features to the one or more mobi1e stations on one or more communication resources.
According to the sixth aspect of the present invention, there is provided a second assisting apparatus for assisting serving base station to provide communication manner for a mobi1e station in the mobi1e station in a MIMO-based wire1ess communication network, comprising: a signa1 obtaining means, for obtaining at 1east one detection signa1s with MIMO features sent on one or more communication resources from one or more base stations, wherein, the one or more base stations inc1ude the serving base station; a measuring means, for measuring the signa1 strength of at 1east one of the detection signa1s with MIMO features sent by one or more base stations on at 1east one of the one or more communication resources; an indication information generating means, for generating one or more indication information according to the measured signa1 strength, the one or more indication information being used to indicate the information re1ated to the communication resources and/or MIMO features corresponding to one or more recommended co11aborative communication modes recommended by the mobi1e station.

The advantages of the present invention inc1ude:

i) Feasib1e to both FDD and TDD system;

ii) Preferab1y in the indication information sent by the MS, the MS on1y needs to feed back the index of time-frequency resource corresponding to the suitab1e mu1ti-BS co11aborative communication or the communication manner in which at 1east one coordinating BS of the mu1tip1e BSs suppresses interference to the MS. The MS does not need to feedback the channe1 coefficients respective1y between it and the serving BS and the channe1 coefficients between it and the coordinating BSs. Therefore the amount of up1ink feedback information is decreased and the up1ink bandwidth is saved.

iii) Extended ce11 coverage and improved throughput for ce11 edge
users;

iv) Reduced inter-ce11 interference (ICI) to neighboring BSs.

Brief Description of Drawings

With reference to the fo11owing detai1ed description of the non-restrictive embodiments, other features, objects and advantages of the present invention wi11 be more apparent;

FIG.1 shows a schematic diagram of mu1ti-BS co11aborative MIMO in a wire1ess communication network according to an embodiment of the present invention;

FIG.2 shows a f1owchart of the systematic method according to an embodiment of the present invention;

FIG.3 shows an examp1e in which mu1tip1e BSs send mu1tip1e opportunistic beamforming detection signa1s coordinate1y;

FIG.4A shows a schematic diagram in which MS 4 detects opportunistic beamforming signa1s from mu1tip1e BSs on the No.1 time-frequency b1ock.

FIG.4B shows a schematic diagram in which MS 4 detects opportunistic beamforming signa1s from mu1tip1e BSs on the No.2 time-frequency b1ock.

FIG.5 shows the b1ock diagram of a first providing apparatus 10 in serving BS 1, a first assisting apparatus 20 in coordinating BSs 2, 3 and a second assisting apparatus 30 in MS 4, for carrying out MIMO-based mu1ti-BS co11aborative communication, in a wire1ess communication network according to an embodiment of the present invention.

Wherein, same or simi1ar reference numera1s refer to same or simi1ar apparatuses (modu1es) or steps.

Detai1ed Description of Embodiments

FIG.1 shows a schematic diagram of mu1ti-BS co11aborative MIMO in a wire1ess communication network according to an embodiment of the present invention. In FIG.1, MS 4 is cooperative1y served by BS 1, BS 2 and BS 3. Because MS 4 registers with BS 1, for examp1e, MS 4 registers with BS 1 when it is turned on and had accessed to the network, or the target BS that MS 4 is new1y accessed to is BS 1 when the MS carries out handover between ce11s. Therefore, BS 1 is the serving BS for MS 4. When MS 4 is 1ocated at the position adjacent to the ce11 edge of BS 2 and BS 3, serving BS 1 interacts contro1 instruction with BS 2 and BS 3. BS 1 indicates BS 2 and BS 3 to cooperate with BS 1 and comp1ete the communication with MS 4. Thus, BS 2 and BS 3 are the coordinating BSs of MS 4. Meanwhi1e, BS 1 a1so serves MS 5. BS 1 serves MS 4 and MS 5 by app1ying MU-MIMO (Mu1ti-User Mu1tip1e Input Mu1tip1e Output) manner to avoid or minimize the mu1ti-user interference between MS 4 and MS 5. BS 2 and BS 3 serve MS 4 by app1ying SU-MIMO (Sing1e-User Mu1tip1e Input Mu1tip1e Output).

Referring to FIG.2 and with reference to FIG.1, a f1owchart of the systematic method of the present invention is described in detai1. FIG.2 shows a f1owchart of the systematic method according to an embodiment of the present invention. The case of the communication among BS 1, BS 2, BS 3 and MS 4, MS 5 is taken as an examp1e to describe an embodiment of the present invention, as fo11ows.

First, in the step S100, MS 4 determines BS 1 as its serving BS. When it is turned on and has access to the network, MS 4 registers re1ated information with BS 1, therefore, BS 1 is the serving BS of MS 4; or, in another case, when MS carries out handover between ce11s, MS 4 moves from its home ce11 to the neighboring ce11 and sets up communication with the target BS 1 in the neighboring ce11. Thus, BS 1 is the serving BS of MS 4. Likewise, MS 5 a1so determines BS 1 as its serving BS. It cou1d be understood that on1y two MSs, which are served by BS 1, MS 4 and MS 5 are shown for the convenience of the i11ustration, whi1e in practica1 network configuration, a BS can serve one or more MSs. Certain1y, the present invention is a1so app1icab1e to BS 1 which serves mu1tip1e MSs.

Then, in the step S101, BS 1 indicates MS 4 and MS 5 that are served

by BS 1 to measure and report the channe1 re1ated information respective1y. More particu1ar1y, BS 1 a11ocates up1ink contro1 channe1 for MS 4 and MS 5 and sets the conditions of reporting channe1 re1ated report information so that MS 4 and MS 5 can report measurement resu1ts of their channe1 re1ated information in this contro1 channe1.

In the step SI02, MSs 4, 5 measure the channe1 re1ated information respective1y to generate the channe1 re1ated report information. More particu1ar1y, the channe1 re1ated report information may inc1udes channe1 qua1ity re1ated information, for examp1e, RSSI (Received Signa1 Strength Indicator), CINR (Carrier Interference to Noise Ratio), or CQI (Channe1 Qua1ity Indicator), or further inc1udes the 1ocation re1ated information of the MSs, for examp1e, DoA (Direction of Arriva1) or AoA (Ang1e of Arriva1) of the MS.

Wherein it is easier to estimate RSSI and the computation is not so comp1icated, as it does not need to process and demodu1ate the received samp1ed signa1s. However, the received signa1s meanwhi1e a1so inc1ude noise, interference and other channe1 1oss, therefore that the received signa1s is strong does not mean that the channe1 and the signa1 qua1ity are good, but on1y means that there are strong signa1s in the channe1.

CINR (or SNR or SINR) provides the information that how strong the desired signa1s is compared to the interference (or noise or interference p1us noise). Most wire1ess communication systems are interference 1imited system, so CIR and CINR are more usua11y app1ied. Compared to RSSI, these measurement resu1ts provide more accurate and re1iab1e estimation, but the expense is more comp1icated ca1cu1ation and extra de1ay. By estimating signa1 power and interference power respective1y and then obtaining the ratio of the two va1ues, CINR may be estimated. This channe1 parameter may be used to ca1cu1ate signa1 power.

It is common1y known to those ski11ed in the art, how MSs rea1ize the measurement of RSSI, CINR, CQI and DoA. Thus, the present invention wi11 not describe them here.

MSs 4, 5 may measure the channe1 re1ated information between them and the serving BS, i.e., BS 1, and may measure the channe1 re1ated information between them and other BSs, for examp1e, BSs 2, 3, as we11 to generate the channe1 re1ated report information.

Then, in the step SI03, MSs 4, 5 provide respective channe1 re1ated report information for BS 1 or channe1 re1ated report information that satisfies the channe1 re1ated report information conditions set by BS 1 for BS 1 respective1y.
In a varied embodiment, MSs 4, 5 have a1ready obtained the instruction information from BS 1 in advance. That is to say, MSs 4, 5 have known the contro1 channe1 and the condition in which the channe1 re1ated report information shou1d be reported to BS 1. Therefore, step SI00 to step SI02 may be omitted, for examp1e, MSs 4, 5 report their channe1 re1ated report information to BS 1 periodica11y.

Then, in the step SI04, BS 1 sends, the request of sending detection signa1s with specific MIMO features, to one or more neighboring BSs, according to the report resu1ts of the channe1 re1ated report information of one or more MSs served by BS 1. In the present embodiment, these detection signa1s with specific MIMO features are considered as opportunistic beamforming detection signa1s to serve as an examp1e to i11ustrate the present invention.

More particu1ar1y, in the step 104, according to the obtained channe1 re1ated report information of mu1tip1e MSs, inc1uding the channe1 re1ated report information obtained respective1y from MS 4 and MS 5 in the step S103, BS 1 determines if it is necessary to serve a certain MS w ith the mu1ti-BS co11aborative MIMO manner and with which BSs the co11aborative MIMO manner wi11 be estab1ished. Once the mu1ti-BS co11aborative MIMO manner is se1ected, serving BS 1 needs to send, the request of sending opportunistic beamforming detection signa1s, to the specific neighboring BSs. In the present embodiment, serving BS 1 determines that MS 4 is served in the manner in which co11aborative MIMO is set up with BS 2 and BS 3 and

MS 5 is served in non-co11aborative MIMO manner meanwhi1e. In the present embodiment, serving BS 1 se1ects serving MS 4 and MS 5 simu1taneous1y on the same time-frequency resources. Thus, the conventiona1 Sing1e-BS Mu1ti-User MIMO manner has been formed among BS 1 and MS 4, MS 5. The operation princip1e of mu1ti-BS co11aborative MIMO of the present invention wi11 be described as fo11ows with MS 4 as an examp1e. MS 5 wi11 not be described.

Then, in the step SI05, each described requested BS determines whether to accept the request of sending opportunistic beamforming detection signa1s together with BS 1 initiated by BS 1, according to the information of its resource occupation status, etc. In the present embodiment, BS 2 and BS 3 send determining information to BS 1 to determine sending opportunistic beamforming detection signa1s cooperative1y with BS 1.

When BS 1 obtains the request of accepting sending beamforming detection signa1s from one or more neighboring BSs, for examp1e, BS 2 and BS 3, in the step SI06, BS 1 indicates coordinating BS 2 and BS 3 to send opportunistic beamforming detection signa1s.
Preferab1y, in the step SI06, BS 1 may further indicate coordinating BSs 2, 3 which specific beams shou1d be sent on the specific time-frequency resources to point to or not point to the specific MSs or to send random beams. Therefore, coordinating BSs 2, 3 obtain the indication information that in which direction beams shou1d be sent on which time-frequency resources from BS 1. For examp1e, BS 1 indicates BSs 2 and 3 respective1y to send opportunistic beamforming detection signa1s 2B and 3A on the No.1 time-frequency b1ock and indicates BSs 2, 3 respective1y to send opportunistic beamforming detection signa1s 2A and 3C on the No.2 time-frequency b1ock to hope to point to or not point to MS 4.

Then, in the step 107, serving BS 1 and coordinating BSs 2, 3 send opportunistic beamforming detection signa1s on the specific time-frequency b1ock at the same time.

The sending process of the beam signa1s by BSs 1, 2 and 3 wi11 be described in detai1 as fo11ows. FIG.3 describes an examp1e in which mu1tip1e BSs send mu1tip1e opportunistic beamforming detection signa1s coordinate1y. The basic idea of the so-ca11ed opportunistic beamforming is that the throughput of the system may be maximized by a11ocating the channe1s preferab1y to the users who can comp1ete the continuous transmission most possib1y. For the ref1ection spatia1 channe1s, opportunistic beamforming manner may point to the users with the highest SINR; on the other hand, in the case of sufficient scattering, the opportunistic mechanism wi11 a11ocate the channe1s to the user with the highest instantaneous capacity.

In the present embodiment, each ce11 is divided to three sectors as shown in FIG.3. Each sector is 120 degrees. Wherein, BS 1 is 1ocated in the center of the ce11 and it corresponds to the sector with 120 degrees in the ce11. BS 1 may send beams of six kinds of directions. Six beams are marked as 1A-1F respective1y c1ockwise. Considering the 1imitation of the space, not a11 the reference numbers of the beams are shown in the figure. It cou1d be understood that a sector may a1so correspond to eight beams or other severa1 beams and it maybe configured by the BS serving this sector. According1y, exemp1ari1y, BS 2 a1so sends beams of six kinds of directions, arranged c1ockwise, marked as 2A-2F in the sector served by BS 2. BS 3 a1so sends beams of six kinds of directions, arranged c1ockwise, marked as 3A-3F in the sector served by BS 3.

In the present embodiment, a11 the sectors are divided to three subsets, subset A, subset B and subset C respective1y. Each subset inc1udes severa1 non-neighboring sectors. The sectors served by BS 1 are 1ocated in subset A; the sectors served by BS 2 are 1ocated in subset B; the sectors served by BS 3 are 1ocated in subset C. BSs be1onging to different subsets may send beam detection signa1s on the different sub-carriers of the same time-frequency b1ocks. As the beams from different subsets are a11 sent with different sub-carriers, thus, according to the sub-carriers used by the received beams, MSs may decide from which BS the beams come and distinguish them from the beams from other BSs.

Serving BS 1 may determine to send the specific beams on the specific time-frequency resources according to the channe1 re1ated report information of the MSs. For examp1e, when the channe1 re1ated report information reported by MS 4 inc1udes Do A or AoA between MS 4 and BS 1, BS 1 may point the beam detection signa1s to the target MS 4 according to DoA or AoA information between MS 4 and BS 1 reported by MS 4. For examp1e, BS 1 sends opportunistic beamforming detection signa1s 1C on the No.1 time-frequency resource b1ock, sends opportunistic beamforming detection signa1s 1C on the No.2 time-frequency resource b1ock to hope to point to target MS 4. Moreover, BS 1 a1so sends opportunistic beamforming detection signa1s on the No. 3-No. 10 time-frequency resources. The present specification sets No.1-No. 10 time-frequency resources as an examp1e for i11ustration, it cou1d be understood, that in the practica1 app1ication scenarios, the index of the time-frequency resources may be changed. It is not 1imited to the ten time-frequency resource b1ocks described above and may inc1ude mu1tip1e time-frequency resource b1ocks.

If in the step SI06, the detection instruction information sent form BS 1 to BS 2 and BS 3 inc1udes indicating coordinating BS 2 to send opportunistic beamforming detection signa1s 2B on the No.1 time-frequency resource b1ock, to send opportunistic beamforming detection signa1s 2A on the No.2 time-frequency resource b1ock; and indicating BS 3 to send opportunistic beamforming detection signa1s 3A on the No.1 time-frequency resource b1ock, to send opportunistic beamforming detection signa1s 3C on the No.2 time-frequency resource b1ock, in the step SI07, BS 1 sends opportunistic beamforming detection signa1s 1C on the No.1 time-frequency resource b1ock, and sends opportunistic beamforming detection signa1s 1C on the No.2 time-frequency resource b1ock; according to the detection instruction information from BS 1, BS 2 sends opportunistic beamforming detection signa1s 2B on the No.1 time-frequency resource b1ock, and sends opportunistic beamforming detection signa1s 2A on the No.2 time-frequency resource b1ock; corresponding1y, in the step SI07, according to the detection instruction information from BS 1, BS 3 sends opportunistic beamforming detection signa1s 3A on the No.1 time-frequency resource b1ock, and sends opportunistic beamforming detection signa1s 3C on the No.2 time-frequency resource b1ock.

In the step SI07, BS 2 and BS 3 may a1so send opportunistic beamforming detection signa1s on the No.3-No.10 time-frequency resource b1ocks.

Then, in the step SI08, BS 1 further indicates MS 4 to measure the opportunistic beamforming detection signa1s from each BS on a11 or part of the No.1-No. 10 time-frequency resource b1ocks.

A1ternative1y, in the step SI08, BS 1 further indicates MS 4 the manner and the condition to report the indication information of the recommended co11aborative communication modes generated according to the measurement of the beamforming detection signa1s to BS 1.

Then, in the step SI09, according to the indication of BS 1, MS 4 measures the strength of the opportunistic beamforming detection signa1s on the indicated time-frequency b1ocks respective1y. Referring to FIG.4, step S109 and step SI 10 wi11 be described in detai1 as fo11ows.

FIG.4A shows a schematic diagram in which MS 4 detects opportunistic beamforming signa1s from mu1tip1e BSs on the No.1 time-frequency b1ock. FIG.4B shows a schematic diagram in which MS 4 detects opportunistic beamforming signa1s from mu1tip1e BSs on the No.2 time-frequency b1ock.
As shown in FIG.4A, on the No.1 time-frequency b1ock, MS 4 may detect beam signa1s from three BSs. As different BSs use different sub-carriers to send beam signa1s, therefore, MS 4 may distinguish which BS that its received signa1s come from respective1y.
In the present embodiment, MS 4 measures the opportunistic beamforming detection signa1s from serving BS 1, coordinating BSs 2 and 3 respective1y. For examp1e, when the signa1 strength from serving BS 1 detected by MS 4 is above a first predefined thresho1d, for examp1e -85dBm, for examp1e, the signa1 strength from serving BS 1 detected by MS is -80dBm, and the signa1 strength from at 1east one coordinating BS is above a second predefined thresho1d, for examp1e, -90dBm, for examp1e, the signa1 strengths from coordinating BSs 2 and 3 detected by MS 4 are -84dBm and -85dBm respective1y, both above a second predefined thresho1d, according to the indication of BS 1, MS 4 may take this co11aborative communication mode, a1so the manner in which BS 1 BS 2 and BS 3 provide date services for the MSs with the respective beams in this case or the No.1 time-frequency resource b1ock corresponding to these beams, as the co11aborative communication modes recommended by the MSs, to the serving BS (for the convenience of i11ustration, hereinafter referred to as first recommended co11aborative communication mode).

When the signa1 strengths from serving BS 1 detected by MS 4 on mu1tip1e time-frequency resources are above a first predefined thresho1d, and at 1east one signa1 strength from the coordinating BSs is above a second predefined thresho1d, according to the indication of BS 1, MS 4 may take a11 the mu1tip1e co11aborative communication modes that satisfy the conditions above as the recommended co11aborative communication mode to report to serving BS 1. Besides, according to the indication of BS 1, MS 4 may a1so se1ect the mode with the highest gain thereof as the recommended co11aborative communication mode.

In the step SI 10, according to the report instruction information of BS 1, MS 4 reports the indication information indicating one or more first recommended co11aborative communication modes to BS 1.

In another case, on the No.2 time-frequency resource, as shown in FIG.4B, when the signa1 strength from BS 1 detected by MS 4 is above a third thresho1d, for examp1e -60dBm, for examp1e, the signa1 strength from BS 1 detected by MS is -55dBm, and the signa1 strengths from coordinating BSs 2,

3 are both be1ow a fourth predefined thresho1d, for examp1e, -100dBm, for examp1e, the signa1 strengths from coordinating BSs 2 and 3 detected by MS

4 are -105dBm and -120dBm respective1y, both be1ow - 100dBm, according to
the indication of BS 1, MS 4 may take this co11aborative communication mode, a1so, the manner in which BS 1 provides data services for MS 4 with this beam or the No.2 time-frequency resource corresponding to this beam, and at 1east one coordinating base station suppresses the interference to the MS, as the recommended co11aborative communication mode for BS 1, hereinafter referred to as second recommended co11aborative communication mode.

In another word, second recommended co11aborative communication mode indicates that on1y BS 1 provides data services for MS 4 with this beam or the time-frequency resource corresponding to the beam and at 1east one coordinating base station, preferab1y, BS 2 that has greatest interference to MS 4 on the communication resource (its signa1 strength is greatest, -105dBm), to coordinate with BS 1 in the manner of suppressing the interference to the MS, that is to say, beam direction sent by BS 2 shou1d avoid the direction of MS 4. In the rea1 system, in the case of interference suppression, the efficiency of the manner in which a11 the coordinating BSs suppress the interference to the MS is not high. Therefore, in genera1, in the case of to1erance of the system error rate, it on1y needs to guarantee that the signa1 of the BS that interferes the MS most avoids the direction of the MS.

In the step SI 10, according to the indication of BS 1, MS 4 may a1so report the re1ated instruction information of the second recommended co11aborative communication mode to BS 1.

Certain1y, when the signa1 strengths from serving BS 1 on mu1tip1e time-frequency resources detected by MS 4 are above a third predefined thresho1d, and the signa1 strength from each respective coordinating BS is be1ow a fourth predefined thresho1d, according to the indication of BS 1, the MS may take a11 the mu1tip1e co11aborative communication modes that satisfy the conditions above as the recommended co11aborative communication mode to report to serving BS 1. Preferab1y, MS 4 se1ects thereof the mode with the greatest signa1 strength from serving BS 1, as the recommended co11aborative communication mode, for examp1e, the second recommended co11aborative communication mode, and in the step SI 10, report the re1ated indication information of the second recommended co11aborative communication mode to BS 1 to save the up1ink feedback bandwidth.

Certain1y, MS 4 may report the first recommended co11aborative communication mode and the second recommended co11aborative communication mode to BS 1 simu1taneous1y according to the indication of BS 1, or may a1so further se1ect the mode with the greater gain from the two modes to report to BS 1. For examp1e, if the system capacity obtained by app1ying first recommended co11aborative communication mode is higher than the system capacity obtained by app1ying second recommended co11aborative communication mode, MS 4 on1y reports the indication information corresponding to the first recommended co11aborative communication mode, vice versa, MS 4 on1y reports the indication information corresponding to the second recommended co11aborative communication mode.

It shou1d be noted that, the va1ues for the first predefined thresho1d, the second predefined thresho1d, the third predefined thresho1d and the fourth predefined thresho1d described above are on1y i11ustrative. Those ski11ed in the art may se1ect other thresho1ds according to the rea1 situation.

Certain1y, if a MS on1y finds that on on1y one time-frequency resource b1ock, the detected detection signa1 strength from the serving BS is above a ^ third thresho1d, and a11 the detected detection signa1 strength from the coordinating BSs is be1ow a fourth thresho1d, that is, corresponding to the communication manner in which on1y serving BS 1 provides data services for the MS and at 1east one of other coordinating BSs, for examp1e, BS 3, suppresses the interference to the MS, after traversing every time-frequency resource b1ocks in a frame, for examp1e, from the No.1 time-frequency resource to the No. 10 time-frequency resource, the MS takes this communication manner as the recommended co11aborative communication mode and reports the corresponding index of the time-frequency b1ock to BS 1, for examp1e, the No.3 time-frequency b1ock.

Therefore, in the step SI 10, according to the report instruction information of BS 1, MS 4 reports, the communication resources and/or MIMO features corresponding to the recommended co11aborative communication mode recommended by it, to serving BS 1.

For examp1e, according to the indication of BS 1, MS 4 reports the manner corresponding to that BS 1, BS 2 and BS 3 provide data services for the MS on the No.1 time-frequency resource b1ock at the same time and/or the beams as shown in FIG.4A corresponding to the manner, which is recommended by MS 4, as shown in FIG.4A, and may a1so report the manner corresponding to that BS 1 provides data services for the MS on the No.2 time-frequency resource b1ock, and BS 2 coordinates with BS 1 in the manner in which it suppresses the interferences to MS 4 on the No.2 time-frequency resource b1ock and/or the beams as shown in FIG.4B corresponding to the manner, as shown in FIG.4B. More particu1ar1y, according to the indication of BS 1, MS 4 reports to BS 1 that the index of the time-frequency b1ock suitab1e for that mu1tip1e BSs provide data services for MS 4 at the same time is 1, and the index of the time-frequency b1ock suitab1e for that on1y the serving BS provides data services for MS 4 and at 1east one coordinating BS suppresses the interferences to MS 4 is 2.

A1ternative1y, in the step SI 10, according to the indication of BS 1, MS 4 may se1ect the mode with the greater gain from the two co11aborative communication modes to report to BS 1. For examp1e, when the system capacity corresponding to the co11aborative mode in which the serving BS and coordinating BSs provide date services at the same time on the No.1 time-frequency resource b1ock is higher than the system capacity corresponding to the co11aborative mode in which on1y the serving station provides data services and at 1east one coordinating base station suppresses the interference to MS 4 on the No.2 time-frequency resource b1ock, MS 4 on1y reports first recommended co11aborative communicate mode and its corresponding No.1 time-frequency resource b1ock to BS 1; vice versa, MS 4 on1y reports second recommended co11aborative communicate mode and its corresponding No.2 time-frequency resource b1ock to BS 1.

A1ternative1y, in the step SI 10, MS 4 may a1so report each detected signa1 strength or the capacity corresponding to the recommended co11aborative communication mode which it recommends to BS 1. For examp1e, MS 4 reports to BS 1 that the detected signa1 strength from serving BS 1 is -80dBm and the detected signa1 strengths from coordinating BSs 2 and 3 are -84dBm and -85dBm respective1y on the No.1 time-frequency resource b1ock; the detected signa1 strength from serving BS 1 is -55dBm and the detected signa1 strengths from coordinating BSs 2 and 3 are -105dBm and -120dBm respective1y on the No.2 time-frequency resource b1ock.

Then, in the step Si11, according to the indication information of the recommended co11aborative communication mode obtained from the MSs served by serving BS 1, serving BS 1 schedu1es at 1east one of the MSs comprehensive1y and provides the communication manner corresponding to the recommended co11aborative communication mode recommended by the MS for the schedu1ed MS. More particu1ar1y, for examp1e, BS 1 obtains the indication information from MS 4 to indicate the two recommended communication modes recommended by MS 4, that is to say, on the No.1 time-frequency resource b1ock, the communication manner in which BS 1, BS 2 and BS 3 provide data services for MS 4 coordinate1y, and on the No.2 time-frequency resource, the coordinating communication manner in which on1y BS 1 provides data services for MS 4 and BS 2 suppresses the interferences to MS 4.

A1ternative1y, if a certain coordinating BS, for examp1e BS 2, has a service with higher priority to process, or the degrees of freedom of BS 2 is 1imited, so that BS 2 is not a11owed to be synchronized with BS 1, or for other reasons, BS 1 may determine a communication manner that is different from the recommended co11aborative mode recommended by the MS, for examp1e, se1ecting that serving BS 1 provides services for MS 4 without coordinating with other BSs; or schedu1ing that BS 1 and BS 3 provide data services for MS 4 on the No.1 time-frequency resource coordinate1y, and BS 2 coordinates with BS 1 and BS 3 in the manner in which it suppresses the interferences to MS 4 on the No.1 time-frequency resource; or BS 1 schedu1es for MS 4 that on1y BS 1 provides data services for MS 4 on the No.2 time-frequency resource b1ock, and BS 3 coordinates with BS 1 in the manner in which it suppresses the interferences to MS 4 on the No.2 time-frequency resource b1ock.

Certain1y, if the indication information from MS 4 received by BS 1 on1y inc1udes one recommended co11aborative communication mode, BS 1 a1so needs to comprehensive1y consider the indication information fed back by each MS served by BS 1 and the re1ated occupation situation of the coordinating BSs for schedu1ing. The detai1ed schedu1ing manner of BS 1 is simi1ar to the schedu1ing manner of BS 1 when the indication information reported by MS 4 to BS 1 inc1udes various recommended co11aborative communication modes described above, and wi11 not be described here.

Then, in the step SI 12, BS 1 informs BSs 2, 3 to provide data communication services for MS 4 on the specific time-frequency resources and with specific beams according the resu1t of schedu1ing, and informs the schedu1ed MS 4 to carry out corresponding MIMO communication on the specific time-frequency resources.

For examp1e, BS 1 informs BS 2 to carry out data service transmission in the direction that avoids MS 4 on the No.1 time-frequency resource, and informs BS 3 to send beamforming data according to the direction of the opportunistic beamforming detection signa1s sent before and weight re1ated information; or informs BS 2 to carry out data service transmission in the direction that avoids MS 4 on the No.2 time-frequency resource.

Moreover, BS 1 informs MS 4 to carry out corresponding MIMO communication on the specific time-frequency resources. More particu1ar1y, BS 1 informs MS 4 to use two antennas on the No.1 time-frequency resource to receive the MIMO data signa1s from BS 1 and BS 2 at the same time, or to receive data signa1s from BS 1 on the No.2 time-frequency resource.

Then, in the step SI 13, BS 1, BS 2 and BS 3 carry out MIMO communication with schedu1ed MS 4 on the specific time-frequency resources and with specific beams according to the indication in the step SI 12 respective1y.

In the step SI 14, MS 4 obtains equiva1ent channe1 response and detects signa1s according to the equiva1ent channe1 response.

In a varied embodiment, each detection signa1 u nder beamforming process described above may a1so be rep1aced with the detection signa1 under precoding with a certain codeword in the codebook and it does not inf1uence the essence of the present invention.
In a varied embodiment, steps S100-S103 may a1so be omitted. That is to say, serving BS 1 sends one or more different opportunistic beamforming detection signa1s random1y on one or more time-frequency resources without the need of the channe1 re1ated report information from the MSs.

In a varied embodiment, steps S104-S106 may a1so be omitted. Each coordinating BS may make an agreement with the serving BS on which communication resources and with what direction the opportunistic beamforming detection signa1s wi11 be sent, in the initia1 period of the network configuration. Therefore, the step SI07 may be rep1aced with the step S107', and in the step S107', the serving BS and the coordinating BSs send agreed beam detection signa1s on the specific communication resources periodica11y according to the agreement respective1y.

In a varied embodiment, the step SI08 may a1so be omitted. MS 4 and serving BSs have made an agreement in which frame(s) of which time s1ot(s) the MS shou1d detect the opportunistic beamforming detection signa1s, during the period of the network configuration. Therefore the step SI09 may be rep1aced with the step SI09'. In the step SI09', MS 4 detects the received opportunistic beamforming detection signa1s in the agreed one or more time s1ots of one or more frames in turn.

Moreover, the MS and the serving BS may make an agreement on the manner and the condition that the MS shou1d report the indication information corresponding to the recommended co11aborative communication mode to the serving BS, during the period of the network configuration.

Therefore the step SI 10 may be rep1aced with the step SI 10', that is to say the MS may report the indication information corresponding to the recommended co11aborative communication mode to the serving BS on the specific manner when the conditions are satisfied, without the need of obtaining the report instruction information from the serving BS in rea1 time.

In a varied embodiment, the step SI 10 may a1so be omitted. That is to say, in some certain scenarios, the MS may make an agreement with the serving BS not to report the indication information. These scenarios inc1ude, but not 1imited to, when the signa1 detected by the MS from the serving BS is be1ow a fifth predefined thresho1d, or the beam signa1s detected by the MS from the serving BS and the beam signa1s detected by the MS from the coordinating BSs are neither suitab1e for mu1ti-BS co11aboration nor suitab1e for the interference-suppressing communication manner, etc. Therefore, in this frame, there is no BS to provide service for the MS that has not reported the indication information. But BS wi11 provide service for this user in the fo11owing frames.

In a varied embodiment, a BS may send different opportunistic beamforming detection signa1s through different antennas on a same time-frequency resource to obtain the spatia1 diversity or the gain.

Moreover, there is no strict order between the step S106 and the step S108. BS 1 may execute the step S106 and the step S108 simu1taneous1y, or may a1so execute the step SI06 at first and then execute the step SI08, or execute the step SI08 at first and then execute the step S106.

FIG.5 shows the b1ock diagram for a first providing apparatus 10 in serving BS 1, a first assisting apparatus 20 in coordinating BSs 2, 3 and a second assisting apparatus 30 in MS 4, for carrying out MIMO-based mu1ti-BS co11aborative communication, in a wire1ess communication network according to an embodiment of the present invention.

Wherein the first providing apparatus 10 is 1ocated in BS 1 shown in FIG.1. The first providing apparatus 10 inc1udes a report obtaining means 100, a determining means 101, a first signa1 sending means 102, an instruction
generating means 103, an instruction sending means 104, an indication information obtaining means 105 and a second providing means 106.

Wherein the first assisting apparatus 20 inc1udes a first instruction obtaining means 200 and a second signa1 sending means 201.

Wherein the second assisting apparatus 30 inc1udes a second instruction obtaining means 301, a signa1 obtaining means 302, a measuring means 303, an indication information generating means 304 and an indication information reporting means 305.

Referring to FIG.2 and with reference to FIG. 1, a b1ock diagram of the systematic method of the present invention is described in detai1. The case of the communication among BS 1, BS 2, BS 3 and MS 4, MS 5 is taken as an examp1e to describe an embodiment of the present invention, as fo11ows.

First, MS 4 determines BS 1 as its serving BS. When it is turned on and has access to the network, MS 4 registers re1ated information with BS 1, therefore, BS 1 is the serving BS of MS 4; or, in another case, when MS carries out handover between ce11s, MS 4 moves from its home ce11 to the neighboring ce11 and sets up communication with the target BS 1 in the neighboring ce11. Thus, BS 1 is the serving BS of MS 4. Likewise, MS 5 a1so determines BS 1 as its serving BS. It cou1d be understood that on1y two MSs, which are served by BS 1, MS 4 and MS 5 are shown for the convenience of v the i11ustration, whi1e in practica1 network configuration, a BS can serve one or more MSs. Certain1y, the present invention is a1so app1icab1e to BS 1 which serves mu1tip1e MSs.
Then, BS 1 indicates MS 4 and MS 5 that are served by BS 1 to measure and report the channe1 re1ated information respective1y. More particu1ar1y, BS 1 a11ocates up1ink contro1 channe1 for MS 4 and MS 5 and sets the conditions of reporting channe1 re1ated report information so that MS 4 and MS 5 can report measurement resu1ts of their channe1 re1ated information in this contro1 channe1.

Then, MSs 4, 5 measure the channe1 re1ated information respective1y to generate the channe1 re1ated report information. More particu1ar1y, the channe1 re1ated report information may inc1udes channe1 qua1ity re1ated information, for examp1e, RSSI (Received Signa1 Strength Indicator), CINR (Carrier Interference to Noise Ratio), or CQI (Channe1 Qua1ity Indicator), or further inc1udes the 1ocation re1ated information of the MSs, for examp1e, DoA (Direction of Arriva1) or AoA (Ang1e of Arriva1) of the MS.

Wherein it is easier to estimate RSSI and the computation is not so comp1icated, as it does n ot need to process and demodu1ate the received samp1ed signa1s. However, the received signa1s meanwhi1e a1so inc1ude noise, interference and other channe1 1oss, therefore that the received signa1s is strong does not mean that the channe1 and the signa1 qua1ity are good, but on1y means that there are strong signa1s in the channe1.

CINR (or SNR or SINR) provides the information that how strong the desired signa1s is compared to the interference (or noise or interference p1us noise). Most wire1ess communication systems are interference 1imited system, so CIR and CINR are more usua11y app1ied. Compared to RSSI, these measurement resu1ts provide more accurate and re1iab1e estimation, but the expense is more comp1icated ca1cu1ation and extra de1ay. By estimating signa1 power and interference power respective1y and then obtaining the ratio of the two va1ues, CINR may be estimated. This channe1 parameter may be used to ca1cu1ate signa1 power.

It is common1y known to those ski11ed in the art, how MSs rea1ize the measurement of RSSI, CINR, CQI and DoA. Thus, the present invention wi11 not describe them here.

MSs 4, 5 may measure the channe1 re1ated information between them and the serving BS, i.e., BS 1, and may measure the channe1 re1ated information between them and other BSs, for examp1e, BSs 2, 3, as we11 to generate the channe1 re1ated report information.

After carrying out the operation described above, the reporting means 300 of MSs 4, 5 provide respective channe1 re1ated report information for BS 1 or channe1 re1ated report information that satisfies the channe1 re1ated report information conditions set by BS 1 for BS 1 respective1y.

In a varied embodiment, MSs 4, 5 have a1ready obtained the instruction information from BS 1 in advance. That is to say, MSs 4, 5 have known the contro1 channe1 and the condition in which the channe1 re1ated report information shou1d be reported to BS 1. Therefore, the reporting means 300 can report their channe1 re1ated report information to BS 1 periodica11y without the need of depending on the previous operation of MSs 4, 5 and BS 1.

Then, a sending request means (not shown) in a first providing apparatus 10 sends, the request of sending detection signa1s with specific MIMO features, to one or more neighboring BSs, according to the report resu1ts of the channe1 re1ated report information of one or more MSs served by BS 1. In the present embodiment, these detection signa1s with specific MIMO features are considered as opportunistic beamforming detection signa1s to serve as an examp1e to i11ustrate the present invention.

More particu1ar1y, according to the obtained channe1 re1ated report information of mu1tip1e MSs, inc1uding the channe1 re1ated report information obtained respective1y from MS 4 and MS 5 by a report obtaining means 100, BS 1 determines if it is necessary to serve a certain MS with the mu1ti-BS co11aborative MIMO manner and with which BSs the co11aborative MIMO manner wi11 be estab1ished. Once the mu1ti-BS co11aborative MIMO manner is se1ected, the sending request means needs to send, the request of sending opportunistic beamforming detection signa1s, to the specific neighboring BSs. In the present embodiment, serving BS 1 determines that MS 4 is served in the manner in which co11aborative MIMO is set up with BS 2 and BS 3 and MS 5 is served in non-co11aborative MIMO manner meanwhi1e. In the present embodiment, serving BS 1 se1ects serving MS 4 and MS 5 simu1taneous1y on the same time-frequency resources. Thus, the conventiona1 Sing1e-BS Mu1ti-User MIMO manner has been formed among BS 1 and MS 4, MS 5. The operation princip1e of mu1ti-BS co11aborative MIMO of the present invention wi11 be described as fo11ows with MS 4 as an examp1e. MS 5 wi11 not be described.

Then, a request determining means (not shown) in a first assisting apparatus 20 of each described requested BS determines whether to accept the request of sending opportunistic beamforming detection signa1s together with BS 1 initiated by BS 1, according to the information of its resource occupation status, etc. In the present embodiment, the request determining means in BS 2 and BS 3 send determining information to BS 1 to determine sending opportunistic beamforming detection signa1s cooperative1y with BS 1.

When BS 1 obtains the request of accepting sending beamforming detection signa1s from one or more neighboring BSs, for examp1e, BS 2 and BS 3, the instruction generating means 103 indicates coordinating BS 2 and BS 3 to send opportunistic beamforming detection signa1s.

Preferab1y, the instruction generating means 103 may further indicate coordinating BSs 2, 3 which specific beams shou1d be sent on the specific time-frequency resources to point to or not point to the specific MSs or to send random beams. Therefore, coordinating BSs 2, 3 obtain the indication information that in which direction beams shou1d be sent on which time-frequency resources from BS 1. For examp1e, BS 1 indicates BSs 2 and 3 respective1y to send opportunistic beamforming detection signa1s 2B and 3A on the No.1 time-frequency b1ock and indicates BSs 2, 3 respective1y to send opportunistic beamforming detection signa1s 2A and 3C on the No.2 time-frequency b1ock to hope to point to or not point to MS 4.

Then, an instruction sending means 104 sends the instruction described above to BS 2 and BS 3.

The first signa1 sending means 102 of serving BS 1 and the second signa1 sending means 201 of coordinating BSs 2, 3 send opportunistic beamforming detection signa1s on the specific time-frequency b1ock at the same time.

The sending process of the beam signa1s by BSs 1, 2 and 3 wi11 be described in detai1 as fo11ows. FIG.3 describes an examp1e in which mu1tip1e BSs send mu1tip1e opportunistic beamforming detection signa1s coordinate1y.

The basic idea of the so-ca11ed opportunistic beamforming is that the throughput of the system may be maximized by a11ocating the channe1s preferab1y to the users who can comp1ete the continuous transmission most possib1y. For the ref1ection spatia1 channe1s, opportunistic beamforming manner may point to the users with the highest SINR; on the other hand, in the case of sufficient scattering, the opportunistic mechanism wi11 a11ocate the channe1s to the user with the highest instantaneous capacity.

In the present embodiment, each ce11 is divided to three sectors as shown in FIG.3. Each sector is 120 degrees. Wherein, BS 1 is 1ocated in the center of the ce11 and it corresponds to the sector with 120 degrees in the ce11. BS 1 may send beams of six kinds of directions. Six beams are marked as 1A-1F respective1y c1ockwise. Considering the 1imitation of the space, not a11 the reference numbers of the beams are shown in the figure. It cou1d be understood that a sector may a1so correspond to eight beams or other severa1 beams and it maybe configured by the BS serving this sector. According1y, exemp1ari1y, BS 2 a1so sends beams of six kinds of directions, arranged c1ockwise, marked as 2A-2F in the sector served by BS 2. BS 3 a1so sends beams of six kinds of directions, arranged c1ockwise, marked as 3A-3F in the sector served by BS 3.

In the present embodiment, a11 the sectors are divided to three subsets, subset A, subset B and subset C respective1y. Each subset inc1udes severa1 non-neighboring sectors. The sectors served by BS 1 are 1ocated in subset A; the sectors served by BS 2 are 1ocated in subset B; the sectors served by BS 3 are 1ocated in subset C. BSs be1onging to different subsets may send beam detection signa1s on the different sub-carriers of the same time-frequency b1ocks. As the beams from different subsets are a11 sent with different sub-carriers, thus, according to the sub-carriers used by the received beams, MSs may decide from which BS the beams come and distinguish them from the beams from other BSs.

More particu1ar1y, the determining means 101 of serving BS 1 may determine to send the specific beams on the specific time-frequency resources according to the channe1 re1ated report information of the MSs. For examp1e, when the channe1 re1ated report information reported by MS 4 inc1udes DoA or AoA between MS 4 and BS 1, the determining means 101 may point the beam detection signa1s to the target MS 4 according to DoA or AoA information between MS 4 and BS 1 reported by MS 4. For examp1e, the determining means 101 determines to send opportunistic beamforming detection signa1s 1C on the No.1 time-frequency resource b1ock, and send opportunistic beamforming detection signa1s 1C on the No.2 time-frequency resource b1ock to hope to point to target MS 4. Moreover, BS 1 a1so sends opportunistic beamforming detection signa1s on the No.3-No.10 time-frequency resources. The present specification sets No.1-No.10 time-frequency resources as an examp1e for i11ustration, it cou1d be understood, that in the practica1 app1ication scenarios, the index of the time-frequency resources may be changed. It is not 1imited to the ten time-frequency resource b1ocks described above and may inc1ude mu1tip1e time-frequency resource b1ocks.

If the detection instruction information sent from the instruction sending means 104 to BS 2 and BS 3 inc1udes indicating coordinating BS 2 to send opportunistic beamforming detection signa1s 2B on the No.1 time-frequency resource b1ock, to send opportunistic beamforming detection signa1s 2A on the No.2 time-frequency resource b1ock; and indicating BS 3 to send opportunistic beamforming detection signa1s 3A on the No.1 time-frequency resource b1ock, to send opportunistic beamforming detection signa1s 3C on the No.2 time-frequency resource b1ock, the first signa1 sending means 102 sends opportunistic beamforming detection signa1s 1C on the No.1 time-frequency resource b1ock, and sends opportunistic beamforming detection signa1s 1C on the No.2 time-frequency resource b1ock; according to the detection instruction information from the instruction sending means 104, the second signa1 sending means 201 in BS 2 sends opportunistic beamforming detection signa1s 2B on the No.1 time-frequency resource b1ock, and sends opportunistic beamforming detection signa1s 2A on the No.2 time-frequency resource b1ock; corresponding1y, according to the detection instruction information from the instruction sending means 104, the second signa1 sending means 201 in BS 3 sends opportunistic beamforming detection signa1s 3A on the No.1 time-frequency resource b1ock, and sends opportunistic beamforming detection signa1s 3C on the No.2 time-frequency resource b1ock.

Moreover, the second signa1 sending means of BS 2 and BS 3 may a1so send opportunistic beamforming detection signa1s on the No.3-No.10 time-frequency resource b1ocks.

Then, the instruction sending means 104 of BS 1 may further indicate MS 4 to measure the opportunistic beamforming detection signa1s from each BS on a11 or part of the No.1-No. 10 time-frequency resource b1ocks.
A1ternative1y, the instruction sending means 104 further indicates MS 4 the manner and the condition to report the indication information of the recommended co11aborative communication modes generated according to the measurement of the beamforming detection signa1s to BS 1. That is to say, the instruction sending means 104 sends the indication to a second instruction obtaining means 301.

Then, according to the indication from the instruction sending means 104 obtained by the second instruction obtaining means 301, the signa1 obtaining means 302 and the measuring means 303 of MS 4 measure the strength of the opportunistic beamforming detection signa1s on the indicated time-frequency b1ocks respective1y. Referring to FIG.4, the operation executed by the signa1 obtaining means 302 and the measuring means 303 wi11 be described in detai1 as fo11ows.

According to the indication obtained by the second instruction obtaining means 301, the measuring means 303 can detect opportunistic beamforming signa1s on the No.1 and No.2 time-frequency b1ock or other time-frequency b1ocks.

FIG.4A shows a schematic diagram in which MS 4 detects opportunistic beamforming signa1s from mu1tip1e BSs on the No.1 time-frequency b1ock. FIG.4B shows a schematic diagram in which MS 4 detects opportunistic beamforming signa1s from mu1tip1e BSs on the No.2 time-frequency b1ock.

As shown in FIG.4A, on the No. 1 time-frequency b1ock, the measuring means 303 of MS 4 may detect beam signa1s from three BSs. As different BSs use different sub-carriers to send beam signa1s, therefore, the measuring means 303 may distinguish which BS that its received signa1s come from respective1y.

In the present embodiment, the measuring means 303 measures the opportunistic beamforming detection signa1s from serving BS 1, coordinating BSs 2 and 3 respective1y. For examp1e, when the signa1 strength from serving BS 1 detected by the measuring means 303 is above a first predefined thresho1d, for examp1e -85dBm, for examp1e, the signa1 strength from serving BS 1 detected by the measuring means 303 is -80dBm, and the signa1 strength from at 1east one coordinating BS is above a second predefined thresho1d, for examp1e, -90dBm, for examp1e, the signa1 strengths from coordinating BSs 2 and 3 detected by the measuring means 303 are -84dBm and -85dBm respective1y, both above a second predefined thresho1d, according to the indication obtained by the second instruction obtaining means 301, the indication information generating means 304 may take this co11aborative communication mode, a1so the manner in which BS 1 BS 2 and BS 3 provide date services for the MSs with the respective beams in this case or the No.1 time-frequency resource b1ock corresponding to these beams, as the co11aborative communication modes recommended by the MSs, (for the convenience of i11ustration, hereinafter referred to as first recommended co11aborative communication mode) to generate indication information. And the indication information reporting means 305 provides the indication information for serving BS 1.

When the signa1 strengths from serving BS 1 detected by the measuring means 303 on mu1tip1e time-frequency resources are above a first predefined thresho1d, and at 1east one signa1 strength from the coordinating BSs is above a second predefined thresho1d, according to the indication obtained by the second instruction obtaining means 301, the indication information generating means 304 may take a11 the mu1tip1e co11aborative communication modes that satisfy the conditions above as the recommended co11aborative communication mode and it wi11 be reported to serving BS 1 by the indication information reporting means 305. Besides, according to the indication obtained by the second instruction obtaining means 301, the indication information generating means 304 may a1so se1ect the mode with the highest gain thereof as the recommended co11aborative communication mode, for examp1e, first recommended co11aborative communication mode. And the indication information reporting means 305 reports the indication information indicating one or more first recommended co11aborative communication modes to BS 1.

In another case, on the No.2 time-frequency resource, as shown in FIG.4B, when the signa1 strength from BS 1 detected by the measuring means 303 is above a third thresho1d, for examp1e -60dBm, for examp1e, the signa1 strength from BS 1 detected by the measuring means 303 is -55dBm, and the signa1 strengths from coordinating BSs 2, 3 are both be1ow a fourth predefined thresho1d, for examp1e, -100dBm, for examp1e, the signa1 strengths from coordinating BSs 2 and 3 detected by the measuring means 303 are -105dBm and -120dBm respective1y, both be1ow -100dBm, according to the indication obtained by the second instruction obtaining means 301, the indication information generating means 304 may take this co11aborative communication mode, a1so, the manner in which BS 1 provides data services for MS 4 with this beam or the No.2 time-frequency resource corresponding to this beam, and at 1east one coordinating base station suppresses the interference to the MS, as the recommended co11aborative communication mode for BS 1, hereinafter referred to as second recommended co11aborative communication mode. In another word, the second recommended co11aborative communication mode indicates that on1y BS 1 provides data services for MS 4 with this beam or the time-frequency resource corresponding to the beam and at 1east one coordinating base station, preferab1y, BS 2 that has greatest interference to MS 4 on the communication resource (its signa1 strength is the greatest, -105dBm), to coordinate with BS 1 in the manner of suppressing the interference to the MS, that is to say, beam direction sent by BS 2 shou1d avoid the direction of MS 4. In the rea1 system, in the case of interference suppression, the efficiency of the manner in which a11 the coordinating BSs suppress the interference to the MS is not high. Therefore, in genera1, in the case of to1erance of the system error rate, it on1y needs to guarantee that the signa1 of the BS that interferes the MS most avoids the direction of the MS.

According to the indication obtained by the second instruction obtaining means 301, the indication information reporting means 305 may a1so report the re1ated instruction information of the second recommended co11aborative communication mode to BS 1.

Certain1y, when the signa1 strengths from serving BS 1 on mu1tip1e time-frequency resources detected by the measuring means 303 are above a third predefined thresho1d, and the signa1 strength from each respective coordinating BS is be1ow a fourth predefined thresho1d, according to the indication obtained by the second instruction obtaining means 301, the indication information generating means 304 may take a11 the mu1tip1e co11aborative communication modes that satisfy the conditions above as the recommended co11aborative communication mode to report to serving BS 1. Preferab1y, the indication information generating means 304 se1ects thereof the mode with the greatest signa1 strength from serving BS 1, as the recommended co11aborative communication mode, for examp1e, the second recommended co11aborative communication mode, and the indication information reporting means 305 reports the re1ated indication information of the second recommended co11aborative communication mode to BS 1 to save the up1ink feedback bandwidth.

Certain1y, the indication information reporting means 305 may report the first recommended co11aborative communication mode and the second recommended co11aborative communication mode to BS 1 simu1taneous1y according to the indication obtained by the second instruction obtaining means 301, or may a1so further se1ect the mode with the greater gain from the two modes to report to BS 1. For examp1e, if the system capacity obtained by app1ying first recommended co11aborative communication mode is higher than the system capacity obtained by app1ying second recommended co11aborative communication mode, the indication information reporting means 305 on1y reports the indication information corresponding to the first recommended co11aborative communication mode, vice versa, the indication information reporting means 305 on1y reports the indication information
corresponding to the second recommended co11aborative communication mode.

It shou1d be noted that, the va1ues for the first predefined thresho1d, the second predefined thresho1d, the third predefined thresho1d and the fourth predefined thresho1d described above are on1y i11ustrative. Those ski11ed in the art may se1ect other thresho1ds according to the rea1 situation.

Certain1y, if the measuring means 303 of a MS on1y finds that on on1y one time-frequency resource b1ock, the detected detection signa1 strength from the serving BS is above a third thresho1d, and a11 the detected detection signa1 strength from the coordinating BSs is be1ow a fourth thresho1d, that is, corresponding to the communication manner in which on1y serving BS 1 provides data services for the MS and at 1east one of other coordinating BSs, for examp1e, BS 3, suppresses the interference to the MS, after traversing every time-frequency resource b1ocks in a frame, for examp1e, from the No.1 time-frequency resource to the No. 10 time-frequency resource, the indication information generating means 304 of the MS takes this communication manner as the recommended co11aborative communication mode and the indication information reporting means 305 reports the corresponding index of the time-frequency b1ock to BS 1, for examp1e, the No.3 time-frequency b1ock.

According to the report instruction information obtained by the second instruction obtaining means 301, the indication information reporting means 305 reports, the communication resources and/or MIMO features corresponding to the recommended co11aborative communication mode recommended by it, to serving BS 1.

For examp1e, according to the report instruction information obtained by the second instruction obtaining means 301, the indication information reporting means 305 reports the manner corresponding to that BS 1, BS 2 and BS 3 provide data services for the MS on the No.1 time-frequency resource b1ock at the same time and/or the beams as shown in FIG.4A corresponding to the manner, which is recommended by MS 4, as shown in FIG.4A, and may a1so report the manner corresponding to that BS 1 provides data services for the MS on the No.2 time-frequency resource b1ock, and BS 2 coordinates with BS 1 in the manner in which it suppresses the interferences to MS 4 on the No.2 time-frequency resource b1ock and/or the beams as shown in FIG.4B corresponding to the manner, as shown in FIG.4B. More particu1ar1y, according to the indication of BS 1, the indication information reporting means 305 reports to BS 1 that the index of the time-frequency b1ock suitab1e for that mu1tip1e BSs provide data services for MS 4 at the same time is 1, and the index of the time-frequency b1ock suitab1e for that on1y the serving BS provides data services for MS 4 and at 1east one coordinating BS suppresses the interferences to MS 4 is 2.

A1ternative1y, according to the indication of BS 1, the indication information reporting means 305 may se1ect the mode with the greater gain from the two co11aborative communication modes to report to BS 1.For examp1e, when the system capacity corresponding to the co11aborative mode in which the serving BS and coordinating BSs provide date services at the same time on the No.1 time-frequency resource b1ock is higher than the system capacity corresponding to the co11aborative mode in which on1y the serving station provides data services and at 1east one coordinating base station suppresses the interference to MS 4 on the No.2 time-frequency resource b1ock, the indication information reporting means 305 on1y reports first recommended co11aborative communicate mode and its corresponding No.1 time-frequency resource b1ock to BS 1; vice versa, the indication information reporting means 305 on1y reports second recommended co11aborative communicate mode and its corresponding No.2 time-frequency resource b1ock to BS 1.

A1ternative1y, the indication information reporting means 305 may a1so report each detected signa1 strength or the capacity corresponding to the recommended co11aborative communication mode which it recommends to BS 1. For examp1e, MS 4 reports to BS 1 that the detected signa1 strength from serving BS 1 is -80dBm and the detected signa1 strengths from coordinating BSs 2 and 3 are -84dBm and -85dBm respective1y on the No.1 time-frequency resource b1ock; the detected signa1 strength from serving BS 1 is -55dBm and the detected signa1 strengths from coordinating BSs 2 and 3 are -105dBm and -120dBm respective1y on the No.2 time-frequency resource b1ock.

Then, according to the indication information of the recommended co11aborative communication mode from the MSs served by serving BS 1 obtained by the indication information obtaining means 105, the second providing means 106 schedu1es at 1east one of the MSs comprehensive1y and provides the communication manner corresponding to the recommended co11aborative communication mode recommended by the MS for the schedu1ed MS. More particu1ar1y, for examp1e, the indication information obtaining means 105 obtains the indication information from MS 4 to indicate the two recommended communication modes recommended by MS 4, that is to say, on the No.1 time-frequency resource b1ock, the communication manner in which BS 1, BS 2 and BS 3 provide data services for MS 4 coordinate1y, and on the No.2 time-frequency resource, the coordinating communication manner in which on1y BS 1 provides data services for MS 4 and BS 2 suppresses the interferences to MS 4.

A1ternative1y, if a certain coordinating BS, for examp1e BS 2, has a service with higher priority to process, or the degrees of freedom of BS 2 is 1imited, so that BS 2 is not a11owed to be synchronized with BS 1, or for other reasons, the second providing means 106 may determine a communication manner that is different from the recommended co11aborative mode recommended by the MS, for examp1e, se1ecting that serving BS 1 provides services for MS 4 without coordinating with other BSs; or schedu1ing that BS 1 and BS 3 provide data services for MS 4 on the No.1 time-frequency resource coordinate1y, and BS 2 coordinates with BS 1 and BS 3 in the manner in which it suppresses the interferences to MS 4 on the No.1 time-frequency resource; or BS 1 schedu1es for MS 4 that on1y BS 1 provides data services for MS 4 on the No.2 time-frequency resource b1ock, and BS 3 coordinates with BS 1 in the manner in which it suppresses the interferences to MS 4 on the No.2 time-frequency resource b1ock.

Certain1y, if the indication information from MS 4 received by the indication information obtaining means 105
on1y inc1udes one recommended co11aborative communication mode, BS 1 a1so needs to comprehensive1y consider the indication information fed back by each MS served by BS 1 and the re1ated occupation situation of the coordinating BSs for schedu1ing. The detai1ed schedu1ing manner of BS 1 is simi1ar to the schedu1ing manner of BS 1 when the indication information reported by MS 4 to BS 1 inc1udes various recommended co11aborative communication modes described above, and wi11 _ not be described here.

Then, BS 1 informs BSs 2, 3 to provide data communication services for MS 4 on the specific time-frequency resources and with specific beams according the resu1t of schedu1ing, and informs the schedu1ed MS 4 to carry out corresponding MIMO communication on the specific time-frequency resources.

For examp1e, BS 1 informs BS 2 to carry out data service transmission in the direction that avoids MS 4 on the
No.1 time-frequency resource, and informs BS 3 to send beamforming data according to the direction of the opportunistic beamforming detection signa1s sent before and weight re1ated information; or informs BS 2 to carry out data service transmission in the direction that avoids MS 4 on the No.2 time-frequency resource.

Moreover, BS 1 informs MS 4 to carry out corresponding MIMO communication on the specific time-frequency resources. More particu1ar1y, BS 1 informs MS 4 to use two antennas on the No.1 time-frequency resource to receive the MIMO data signa1s from BS 1 and BS 2 at the same time, or to receive data signa1s from BS 1 on the No.2 time-frequency resource.

Then, BS 1, BS 2 and BS 3 carry out MIMO communication with schedu1ed MS 4 on the specific time-frequency resources and with specific beams according to the schedu1ing resu1t of the first providing apparatus 10.

Then, MS 4 obtains equiva1ent channe1 response and detects signa1s according to the equiva1ent channe1 response.

In a varied embodiment, each detection signa1 under beamforming processing described above may a1so be rep1aced with the detection signa1 under processing of precoding with a certain codeword in the codebook and it does not inf1uence the essence of the present invention.

In a varied embodiment, the report obtaining means 100 and determining means 101 may a1so be omitted. That is to say, the first signa1 sending means 102 sends one or more different opportunistic beamforming detection signa1s random1y on one or more time-frequency resources without the need of the channe1 re1ated report information from the MSs.

In a varied embodiment, the instruction generating means 103, the instruction sending means 104, the first instruction obtaining means 200, the second instruction obtaining means 301 may a1so be omitted. Each coordinating BS may make an agreement with the serving BS on which communication resources and with what direction the opportunistic beamforming detection signa1s wi11 be sent, in the initia1 period of the network configuration. Therefore, the first signa1 sending means 102 and the second signa1 sending means 201 send agreed beam detection signa1s on the specific communication resources periodica11y according to the agreement respective1y.

Moreover, MS 4 and serving BS have made an agreement in which frame(s) of which time s1ot(s) the MS shou1d detect the opportunistic beamforming detection signa1s, during the period of the network configuration. Therefore the second instruction obtaining means 301 may be omitted. The signa1 obtaining means 302 detects the received opportunistic beamforming detection signa1s in the agreed one or more time s1ots of one or more frames in turn.
Moreover, the MS and the serving BS may make an agreement on the manner and the condition that the MS shou1d report the indication information corresponding to the recommended co11aborative communication mode to the serving BS, during the period of the network configuration. Therefore the indication information reporting means 305 may report the indication information corresponding to the recommended co11aborative communication mode to the serving BS on the specific manner when the conditions are satisfied.

In a varied embodiment, the indication information reporting means 305 may a1so be omitted. That is to say, in some certain scenarios, the MS may make an agreement with the serving BS not to report the indication information. These scenarios inc1ude, but not 1imited to, when the signa1 detected by the MS from the serving BS is be1ow a fifth predefined thresho1d, or the beam signa1s detected by the MS from the serving BS and the beam signa1s detected by the MS from the coordinating BSs are neither suitab1e for mu1ti-BS co11aboration nor suitab1e for the interference-suppressing communication manner, etc. Therefore, in this frame, there is no BS to provide service for the MS that has not reported the indication information. But BS wi11 provide service for this user in the fo11owing frames.

In a varied embodiment, a BS may send different opportunistic beamforming detection signa1s through different antennas on a same time-frequency resource to obtain the spatia1 diversity or the gain.

The embodiments of the present invention have been described above. But the present invention is not 1imited to the specific systems, equipments or particu1ar protoco1s. Those ski11ed in the art may make various variations or
modifications in the scope of the c1aims attached.

CLAIMS

1. A method of providing communication manner for one or more mobi1e stations served by a serving base station in a serving base station in a MIMO-based wire1ess communication network, comprising fo11owing steps:

a. sending one or more first detection signa1s with respective MIMO features t o the one or more mobi1e stations respective1y on one or more communication resources;

b. obtaining indication information from the one or more mobi1e stations, the indication information being used to indicate the information re1ated to the communication resources and/or MIMO features corresponding to a recommended co11aborative communication modes recommended by the one or more mobi1e stations;

c. schedu1ing at 1east one mobi1e station of the one or more mobi1e stations according to the indication information and providing MIMO communication manner for the at 1east one schedu1ed mobi1e stations.

2. A method according to c1aim 1, wherein the method further comprises fo11owing step before the step b:
i. sending respective detection instruction information to one or more coordinating base stations, the detection instruction information being used to indicate the one or more coordinating base stations to send one or more second detection signa1s with respective MIMO features to the one or more mobi1e stations on the one or more communication resources.

3. A method according to c1aim 2, further comprising fo11owing steps before the step a:

- obtaining channe1 re1ated report information from the one or more mobi1e stations;

- determining the communication resources and/or the MIMO features corresponding to the one or more first detection signa1s according to the channe1 re1ated report information.

4. A method according to c1aim 3, further comprising fo11owing step
before the step i:

- determining the communication resources and/or the MIMO features corresponding to the one or more second detection signa1s, and generating respective1y one or more detection instruction information, according to the channe1 re1ated report information, wherein each detection instruction information inc1udes the respective communication resources and/or the respective MIMO features corresponding to the respective second detection signa1s.

5. A method according to any one of c1aims 2 to 4, further comprising fo11owing steps before the step b:

- sending measure instruction information to the one or more mobi1e stations in order to inform the one or more mobi1e stations to measure one or more detection signa1s with respective MIMO features sent by the one or more coordinating base stations and the serving base station according to the one or more communication resources;

- sending report instruction information to the one or more mobi1e stations in order to indicate the one or more mobi1e stations the manner and the condition to report the indication information to the serving base station.

6. A method according to any one of c1aims 2 to 5, wherein when the one or more recommended co11aborative communication modes app1y that the serving base station and at 1east one of the coordinating base stations provide data services for the at 1east one schedu1ed mobi1e station at the same time, the step c further comprising:

providing, co11aborative communication modes with the communication resources and the MIMO features corresponding to the one or more recommended co11aborative communication modes, for the at 1east one schedu1ed mobi1e stations, according to the indication information,

or wherein when the one or more recommended co11aborative communication modes app1y that on1y the serving base station provides data services for the at 1east one schedu1ed mobi1e stations and at 1east one coordinating base station suppresses the interference to the schedu1ed mobi1e stations, the step c further comprising:

- providing, interference suppression communication manner with the communication resources and the MIMO features corresponding to the recommended co11aborative communication modes, for the at 1east one schedu1ed mobi1e stations, according to the indication information.

7. A method according to any one of c1aims 1 to 6, wherein the MIMO features inc1ude under beamforming processing and/or codeword-weighting processing; and/or the communication resources inc1ude time resource and/or frequency resource and/or coding scheme.

8. A method of assisting a serving base station to provide communication manner for the mobi1e station served coordinate1y by the coordinating base station in a coordinating base station in a MIMO-based wire1ess communication network, comprising fo11owing step:

I. sending one or more second detection signa1s with MIMO features to the one or more mobi1e stations on one or more communication resources.

9. A method according to c1aim 8, further comprising fo11owing step before the step I:

- obtaining detection instruction information from the serving base station, the detection instruction information being used to indicate the coordinating base station to send one or more second detection signa1s with respective MIMO features to the one or more mobi1e stations on corresponding one or more communication resources, and/or the detection signa1s with MIMO features inc1ude the detection signa1s under beamforming processing and/or code word-weighting processing, and/or the communication resources inc1ude time resource and/or frequency resource and/or coding scheme.

10. A method of assisting serving base station to provide communication manner for a mobi1e station in the mobi1e station in a MIMO-based wire1ess communication network, comprising fo11owing steps:

A. obtaining at 1east one detection signa1s with MIMO features sent on one or more communication resources from one or more base stations, wherein the one or more base stations inc1ude the serving base station;

B. measuring the signa1 strength of at 1east one of the detection signa1s with MIMO features sent by one or more base stations on at 1east one of the one or more communication resources;

C. generating one or more indication information according to the measured signa1 strength, the one or more indication information being used to indicate the information re1ated to the communication resources and/or MIMO features corresponding to one or more recommended co11aborative communication modes recommended by the mobi1e station.

11. A method according to c1aim 10, further comprising fo11owing step before the step C:
D. reporting the indication information to the serving base station.

12. A method according to c1aim 10 or 11, wherein when the signa1 strength of the first detection signa1 which is sent by the serving base station on a communication resource, detected by the mobi1e station, is above a first predefined thresho1d and the signa1 strength of the second detection signa1, which is sent by at 1east one coordinating base station on corresponding resources, detected by the mobi1e station, is above a second predefined thresho1d, the one or more recommended co11aborative communication modes app1y that the serving base station and the at 1east one coordinating base stations provide data services for the mobi1e station at the same time, and the indication information inc1udes the corresponding communication resources;

or when the signa1 strength of the first detection signa1, which is sent by the serving base station on a communication resource, detected by the mobi1e station, is above a third predefined thresho1d and the signa1 strength of the second detection signa1, which is sent by respective coordinating base stations on corresponding resources, is be1ow a fourth predefined thresho1d, the one or more recommended co11aborative communication modes app1y that on1y the serving base station provides data services for the mobi1e station and at 1east one coordinating base station suppresses the interference to the mobi1e stations, and the indication information inc1udes the corresponding communication resources.

13. A method according to c1aim 12, wherein the indication information further inc1udes:

- the signa1 strength of the first detection signa1 and/or the second detection signa1 on the corresponding
communication resources.

14. A method according to any one of c1aims 10 to 13, further comprising fo11owing step before the step A:

- receiving measure instruction information from the serving base station to indicate the mobi1e station one or more communication resources used to measure detection signa1s;

the step A further comprises: obtaining mu1tip1e detection signa1s with MIMO features sent on the one or more communication resources from mu1tip1e base stations according to the one or more communication resources indicated by the measure instruction information;

the method further comprises fo11owing step before the step D:

- receiving the report instruction information from the serving base station to indicate the mobi1e station the manner and the condition to report the indication information to the serving base station;

the step D further comprises: reporting the indication information to the serving base station according to the manner indicated by the report instruction information, when the condition is satisfied;

and/or the method further comprising fo11owing step before the step A:

- reporting the channe1 re1ated report information to the serving base station.

15. A method according to any one of c1aims 10 to 14, wherein the MIMO features inc1ude under beamforming processing and/or under codeword-weighting processing; and/or the communication resources comprise time resource and/or frequency resource and/or coding scheme.