TECHNICAL FIELD

The present disclosure relates to the field of signals multiplexing method and reference signal design in communication system.

BACKGROUND

DMRS (Demodulation Reference Signal) or UE (User Equipment) specific reference signal is one of RS (Reference Signals) used in LTE-A (Long-Term Evolution-Advanced) (release-10, release-11 , etc). DMRS is the same precoded as the data part in a LTE-A system, so it can provide the channel estimation for demodulation.

Fig.1 is a schematic diagram showing an example of DMRS multiplexed. Fig.1 shows a structure of RB (resource block) and DMRS. In Fig.1 , there is shown one RB. The abscissa axis (T) of the RB represents time (OFDM symbols), and its vertical axis (F) represents width of frequency band (sub-carriers). For the RB, the abscissa axis is divided into 14 sections, each of which forms an OFDM symbol in the vertical axis direction. The vertical axis is divided into 12 sections, each of which forms a sub-carrier in the abscissa axis direction. Each small block within the RB represents a RE (resource element), and all 12X14 REs of the RB form a sub-frame, which includes slot 1 and slot 2 along the abscissa axis direction. It is shown in Fig.1 that the first three symbols from the left side of the RB are used as a control region. The remaining part of the RB is used to transmit data part, wherein the predetermined number of DMRSs are included in the RB, and allocated in different predetermined locations of the RB. It is shown in Fig.1 that DMRSs are multiplied with OCC (orthogonal cover code) and scrambling sequence, respectively. Fig.1 gives DMRS examples of both rank 1 and rank 2 cases. For the rank 1 case, DMRS can use OCC [1 , 1 ] or OCC [1 ,-1 ] for its only one layer; for the rank 2 case, DMRS uses both OCC [1 , 1 ] and OCC [1 ,-1 ] which are used for one of layers of DMRS respectively. Because two OCCs are orthogonal to each other, for the rank 2 case, although two layers of DMRS occupy the same frequency/time REs, the orthogonality between the two OCCs still guarantees that two layers of DMRS are orthogonal to each other. It is noted that different layers of DMRS can be called different DMRS ports. For example, in Fig.1 , DMRS using OCC [1 , 1 ] can be called port 7 and DMRS using OCC [1 ,-1 ] can be called port 8. When only port 7 or port 8 is used, it is the rank 1 case; when both port 7 and port 8 are used, it is the rank 2 case.

On top of the OCC, there is a scrambling sequence [a1 , a2, a3... , b1 , b2, b3... ] initialized by a random seed. In Fig.1 , in one RE, port 7 and 8 use the same scrambling sequence. The term "same scrambling sequence" here means that the scrambling sequence is initialized by the same random seed. It is well known that a random seed in release-10 is calculated by the following equation (1 ),

random seed = ( n _s / 2}+ \) ^■ (2cell _id +\) ^■ 2 ¹⁶ + SCID (1 ) wherein, n _s represents the slot number (2 slots in Fig.1 constitute one subframe), celljd represents a transmission point ID (cell ID), and SCID is a binary value. As shown from the equation (1 ), in release-10, the DMRS random seed is decided by the slot number, transmission point ID and a binary value SCID. It is possible that in one transmission point, ports 7 and 8 can be configured with different values of SCID. In such case, port 7 and port 8 will use different scrambling sequences [a1 , a2, a3... ] and [b1 , b2, b3... ], for example. This mainly intends for MU (multi-user) operation and it will be discussed later.

Because DMRS is the base of demodulation at the receiver side, how to set the DMRS random seed is very important for different scenarios, which will be elaborated on the following. Co MP scenario

JT (Joint Transmission) is one technique of CoMP (Coordinate Multiple Points). Fig.2 is a schematic diagram showing an exemplary JT scenario. It is shown in Fig.2 that there are two transmission points (or cells) 1 and 2, both of which transmits to one UE (such as a mobile phone, etc) beams consisting of multiple RBs like the RB shown in Fig.1. The two RBs in Fig.2 are simplified representations of the RB in Fig.1.

The principle of JT operation is illustrated in Fig.2. In JT operation, different transmission points transmit identical data and DMRS to a UE, and the identical data and DMRS from different transmission points combine over the air. So the UE can enjoy the diversity gain from multiple transmission points. Therefore, for the JT operation, in order to correctly combine signals from the multiple transmission points, identical DMRS from the multiple transmission points are necessary; otherwise, DMRS from the multiple transmission points can not correctly be combined over the air. In this sense, the same random seed for initializing the scrambling sequence is necessary for JT operation.

However, it is likely that adjacent transmission points (cells) will have different transmission point IDs. For example, in release-10, adjacent transmission points (cells) may have different transmission point (cell) IDs. Because the parameter "celljd" is involved in the random seed calculation as shown in the above equation (1 ), if transmission point IDs of different transmission points are different, their DMRS or DMRS scrambling sequences will also be different. Therefore, for JT operation, the key point is how to guarantee the same DMRS random seed for different transmission points having different transmission point IDs.

Non-CoMP scenario

Fig.3 is a schematic diagram showing an exemplary non-CoMP scenario. Unlike the case of Fig.2, in Fig.3, signals transmitted from two adjacent transmission points 1 and 2 are for different UEs, that is, UE 1 and UE2, respectively, i.e., UE1 receives the signals from the transmission point 1 , and UE2 receives the signals from the transmission point 2. In non-CoMP operation, since the position of DMRS in a RB is fixed, DMRSs from adjacent transmission points may interfere with each other due to their overlapping in frequency and time resources. For example, as shown in Fig.3, the signals transmitted from the transmission point 1 to UE 1 and the signals transmitted from the transmission point 2 to UE 2 overlap each other in frequency and time resources, thus their DMRSs interfere with each other (as indicated by dashed arrows in Fig.3). Therefore, in this case, different DMRS scrambling sequences for adjacent transmission points are necessary to randomize such ICI (inter-cell interference).

However, it is likely that adjacent transmission points (cells) will have the same transmission point ID. For example, in release-11 , adjacent transmission points may have the same transmission point ID. Because the parameter "celljd" is involved in the DMRS random seed calculation as shown in the above equation (1 ), if adjacent transmission points have the same celljd, DMRS scrambling sequences will be initialized by the same random seed, and ICI is generated to the DMRS of the adjacent transmission points. Therefore, for non-CoMP operation, the key point is how to guarantee different DMRS random seeds for adjacent transmission points having the same transmission point ID.

Fig.4 is a schematic diagram showing a comparison between JT scenario and non- CoMP scenario. On the left side of Fig.4, there is shown a JT scenario where adjacent transmission points have different transmission point IDs. In this case, DMRS random seeds for initializing DMRSs of transmission points 1 and 2 are respectively

(ln _s / 2}+ \) - (2ceU_id\ + \) - 2 ¹⁶ and ( n _s / 2}+ \) - (2cell _id2 + \) - 2 ¹⁶ , both of which are obtained from the above equation (1 ) with a default SCID=0. Here, the parameter cellj ^' dl represents the transmission point ID of the transmission point 1 while the parameter cell_id2 represents the transmission point ID of the transmission point 2, and cellj ^' dl is unequal to cell_id2. In order to correctly combine DMRSs from the two transmission points 1 and 2 over the air, their DMRS random seeds are required to be identical especially in the case that their transmission point IDs are not the same. In conclusion, for the JT scenario, the same DMRS seed is necessary because DMRS combining over the air requires identical DMRS of JT transmission points.

On the right side of Fig.4, there is shown a non-CoMP scenario where adjacent transmission points have the same transmission point ID, i.e. celljdl In this case, DMRS random seeds for initializing DMRSs of transmission points 1 and 2 respectively intended for UE1 and UE2 are both ([n _s / 2]+ l) - (2cell _idl + l) - 2 ¹⁶ , which is obtained from the above equation (1 ) with a default SCID=0. In order to randomize ICI (as indicated by dashed arrows in Fig.4) between DMRS from the two transmission points 1 and 2, their DMRS scrambling sequences are required to be different especially in the case that their transmission point IDs are the same. In conclusion, for the non- CoMP, different DMRS seeds are necessary to randomize the ICI from overlapped DMRSs.

For the JT and non-CoMP scenarios as described above, it is concluded that these two scenarios have conflict requirements on DMRS random seed: the JT operation requires the same DMRS random seed while the non-CoMP operation requires different DMRS random seeds.

MU-MIMO scenario

In addition to the above two scenarios, MU-MIMO (Multi-user Multiple Input-Multiple Output) scenario needs to be considered. Fig.5 is a schematic diagram showing an exemplary MU-MIMO scenario. The principle of MU-MIMO operation is illustrated in Fig.5. For MU-MIMO operation, two or more UEs are assigned to the shared frequency/time radio resource. It is shown in Fig.5 that there are one transmission point and two UEs, that is, UE1 and UE2, both of which share the same frequency/time resource. Because the positions of DMRSs overlap, if one UE such as UE1 can estimate the channel of interfering UE such as UE2 from DMRS, then this UE such as UE1 can cancel the MU interference (as indicated by dashed arrows in Fig.5) on its side.

Such UE side interference cancellation depends on whether or not a UE can blindly detect the DMRS of interfering the UE. Fig.6 is a schematic diagram showing an exemplary blind detection. The principle of the blind detection is shown in Fig.6. The freedom of DMRS inside one transmission point (cell) is from 2 aspects: one is from DMRS random seed by setting SCID=0 or 1 ; the other is from OCC by setting OCC as [1 , 1 ] or [1 ,-1 ] (or equivalently choosing DMRS port 7 or 8). Specifically, as shown in Fig.6, assuming that the transmission point ID of the transmission point is cell_id1 , it can be obtained that SeedO - 2 ¹⁶ and

Seed\ = (ln _s /2}+\) - (2ceU_id\ + \) - 2 ¹⁶ +\ from the above equation (1 ) with SCID being 0 or 1. Combination of two different DMRS random seeds and two OCCs results in four different DMRSs: SeedO, OCC [1 , 1 ]; SeedO, OCC [1 , -1 ]; Seedl , OCC [1 , 1 ]; Seedl , OCC [1 , -1 ]. Each of the four different DMRSs is used for one UE. For example, as shown in Fig.6, the DMRS with SeedO and OCC [1 , 1 ] is used for UE0; the DMRS with SeedO and OCC [1 , -1 ] is used for UE1 ; the DMRS with Seedl and OCC [1 , 1 ] is used for UE2; and the DMRS with Seedl and OCC [1 , -1 ] is used for UE3. Because there are totally 4 dimensions of DMRS, one UE can blindly detect whether or not there are one or more of other three UEs' DMRSs on the shared resource. This blind detection is feasible since the detection space is limited within 4 dimensions of DMRS. It is not difficult to find that DMRS random seed design largely affects such blind detection. The release-10 DMRS random seed design enables such blind detection, which should be considered as one design aspect for further improvement on DMRS random seed.

SUMMARY OF THE DISCLOSURE

In one aspect of the present disclosure, there is provided a method of scrambling signals assigned on predetermined radio resources of at least one layer of resource blocks with the same time and frequency resources, comprising the steps of: generating a random seed based on a user equipment specific ID; initializing a scrambling sequence by the random seed; and scrambling the signals with the initialized scrambling sequence. In another aspect of the present disclosure, there is provided a transmission point device for transmitting to a user equipment signals assigned on predetermined radio resources of at least one layer of resource blocks with the same time and frequency resources, comprising: a random seed generation unit which generates a random seed based on a user equipment specific ID; an initialization unit which initializes a scrambling sequence by the random seed; a scrambling unit which scrambles the signals with the initialized scrambling sequence; and a transceiver unit which transmits the resource blocks with the scrambled signals to the user equipment.

In a further aspect of the present disclosure, there is provided a user equipment for receiving from a transmission point signals assigned on predetermined radio resources of at least one layer of resource blocks with the same time and frequency resources, comprising: a transceiver unit which receives the resource blocks from the transmission point; and a demodulation unit which detects the resource blocks in time domain and/or frequency domain to obtain the signals, wherein, the signals are scrambled by a scrambling sequence initialized by a random seed generated based on a user equipment specific ID.

In a further aspect of the present disclosure, there is provided a method of scrambling signals assigned on predetermined radio resources of at least one layer of resource blocks with the same time and frequency resources, comprising the steps of: selecting a random seed from a first random seed generated based on a transmission point ID and a second random seed; initializing a scrambling sequence by the selected random seed; and scrambling the signals with the initialized scrambling sequence. In a further aspect of the present disclosure, there is provided a transmission point device for transmitting to a user equipment signals assigned on predetermined radio resources of at least one layer of resource blocks with the same time and frequency resources, comprising: a selection unit which selects a random seed from a first random seed generated based on a transmission point ID and a second random seed; an initialization unit which initializes a scrambling sequence by the selected random seed; a scrambling unit for scrambling the signals with the initialized scrambling sequence; and a transceiver unit which transmits the resource blocks with the scrambled signals to the user equipment.

In a further aspect of the present disclosure, there is provided a user equipment for receiving from a transmission point signals assigned on predetermined radio resources of at least one layer of resource blocks with the same time and frequency resources, comprising: a transceiver unit which receives the at least one layer of resource blocks from the transmission point; and a demodulation unit which detects the resource blocks in time domain and/or frequency domain to obtain the signals, wherein, the signals are scrambled by a scrambling sequence initialized by a random seed selected from a first random seed generated based on a transmission point ID and a second random seed. In the present disclosure, by generating random seeds for initializing scrambling sequences for DMRSs based on UE specific IDs, identical DMRS from multiple transmission points are guaranteed for the JT scenarios while different DMRSs from adjacent transmission points are guaranteed for the non-CoMP scenarios. Further, by switching between release-10 DMRS random seeds and UE specific DMRS random seeds, the blind detection can be enabled and the orthogonality between UEs can be kept in MU operation, while the conflict requirements for JT and non-CoMP operation can be solved in non-MU operation.

The foregoing is a summary and thus contains, by necessity, simplifications, generalization, and omissions of details; consequently, those skilled in the art will appreciate that the summary is illustrative only and is not intended to be in any way limiting. Other aspects, features, and advantages of the devices and/or processes and/or other subject matters described herein will become apparent in the teachings set forth herein. The summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the present disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only several embodiments in accordance with the disclosure and are, therefore, not to be considered limiting of its scope, the disclosure will be described with additional specificity and detail through use of the accompanying drawings, in which:

Fig.1 is a schematic diagram showing an example of DMRS multiplexed;

Fig.2 is a schematic diagram showing an exemplary JT scenario;

Fig.3 is a schematic diagram showing an exemplary non-CoMP scenario;

Fig.4 is a schematic diagram showing a comparison between JT scenario and non- CoMP scenario;

Fig.5 is a schematic diagram showing an exemplary MU-MIMO scenario;

Fig.6 is a schematic diagram showing an exemplary blind detection;

Fig.7 is a block diagram showing a transmission point device according to the first embodiment of the present disclosure;

Fig.8 is a block diagram showing a UE according to the first embodiment of the present disclosure;

Fig.9 is a schematic diagram showing an example of MU-MIMO DMRSs multiplexed; Fig.10 is a block diagram showing a transmission point device according to the third embodiment of the present disclosure;

Fig.1 1 shows a table for notifying UEs of DMRS ports and DMRS random seeds in release-10 as defined in TS 36.212;

Fig.12 shows a table for notifying UEs of the selection between release-10 random seeds and UE specific random seeds according to the fourth embodiment of the present disclosure;

Fig.13 shows a table for notifying UEs of the selection between release-10 random seeds and UE specific random seeds according to the fifth embodiment of the present disclosure;

Fig.14 is a diagram showing a flow chart of a method of scrambling signals according to the tenth embodiment of the present disclosure; and

Fig.15 is a diagram showing a flow chart of a method of scrambling signals according to the eleventh embodiment of the present disclosure.

DETAILED DESCRIPTION

In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. It will be readily understood that the aspects of the present disclosure can be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated and make part of this disclosure. (First Embodiment)

Fig.7 is a block diagram showing a transmission point device according to the first embodiment of the present disclosure.

The transmission point device 700 according to the first embodiment of the present disclosure is used for communicating with a UE in a communication system. The transmission point device 700 transmits, to the UE, RS signals which are assigned on predetermined locations (radio resource, which means the time and/or frequency resource such as sub-carrier, sub-frame, etc.) of at least one layer of resource blocks with the same time and frequency resources. As shown in Fig.7, the transmission point device 700 may include a random seed generation unit 701 , an initialization unit 702, a scrambling unit 703, and a transceiver unit 704. The random seed generation unit 701 generates a random seed based on a UE specific ID. The initialization unit 702 initializes a scrambling sequence by the random seed generated in the random seed generation unit 701. The scrambling unit 703 scrambles the signals with the scrambling sequence initialized in the initialization unit 702. The transceiver unit 704 transmits the resource blocks with the signals scrambled in the scrambling unit 703 to the UE. It should be noted that RS signals here can be any kinds of RS signals such as DMRS and the like. For sake of simplicity, the following description will focus on the DMRS as an example.

The transmission point device 700 according to the present disclosure may further include a CPU (Central Processing Unit) 710 for executing related programs to process various data and control operations of respective units in the transmission point device 700, a ROM (Read Only Memory) 713 for storing various programs required for performing various process and control by the CPU 710, a RAM (Random Access Memory) 715 for storing intermediate data temporarily produced in the procedure of process and control by the CPU 710, and/or a I/O (Input/Output) unit 717 for inputting for outputting various programs, data and so on. The above random seed generation unit 701 , initialization unit 702, scrambling unit 703, transceiver unit 704, CPU 710, ROM 713, RAM 715 and/or I/O unit 717 etc. may be interconnected via data and/or command bus 720 and transfer signals between one another.

Respective units as described above do not limit the scope of the present disclosure. According to one embodiment of the disclosure, the function of any of the above random seed generation unit 701 , initialization unit 702, scrambling unit 703 and transceiver unit 704 may also be implemented by functional software in combination with the above CPU 710, ROM 713, RAM 715 and/or I/O unit 717 etc.

Since the operations of the initialization unit 702, the scrambling unit 703 and the transceiver unit 704 in the transmission point device 700 are well known to the skilled in the art, the detailed description thereof is omitted here in order to avoid confusing inventive points of the present invention. The detailed description will be given to the operation of the random seed generation unit 701 of the transmission point device 700 below.

The above random seed generation unit 701 generates a random seed for initializing a scrambling sequence for RS signals based on a UE specific ID instead of using a transmission point ID as shown in the equation (1 ). Here, such a UE specific ID may be a global UE specific identification number such as IMSI (International Mobile Subscriber Identification Number). Alternatively, it may also be a UE specific ID assigned to the UE when the UE accesses to a LTE network, such as c-RNTI (Cell_ Radio Network Temporary Identifier).

As an example, equation (2) is used for generating a random seed for initializing a scrambling sequence for RS signals, such as DMRS, based on c-RNTI as follows.

Wherein, c _in it represents the generated random seed, n _s represents the slot number, and n_RNTI is a parameter defined in 3GPP TS 36.213, representing a UE specific ID. It is noted that the parameter "c-RNTI" is a subset of "n-RNTI", which represents different RNTIs, and the "n-RNTI" is the "c-RNTI" in most cases. Thereby, the random seed generation unit 701 may generate the random seed from the equation (2).

Comparing the equation (2) in the present embodiment with the above equation (1 ) for generating DMRS random seed in release-10, it is found that the parameter celljd in the equation (1 ) is no longer involved in the equation (2). Thus, the conflict requirements on DMRS random seed for the JT scenario and the non-CoMP scenario as shown in Fig.4 are solved by using the equation (2). Specifically, in the JT scenario, since adjacent transmission points (cells) all use UE specific IDs to generate DMRS random seeds and accordingly the scrambling sequences, they have the same DMRS even in a case of having different transmission point IDs. In the non-CoMP scenario, since different UEs have different UE specific IDs which are used to generate DMRS random seeds and accordingly the scrambling sequences, they have different DMRSs even in a case of having the same transmission point ID, so that overlapped DMRSs on adjacent transmission points will have different scrambling sequences to randomize the potential ICI.

Fig.8 is a block diagram showing a UE according to the first embodiment of the present disclosure. The UE 800 according to the first embodiment of the present disclosure is used for communicating with a transmission point device in a communication system. The UE 800 receives from the transmission point device the RS signals which are assigned on predetermined locations (radio resource, which means the time and/or frequency resource such as sub-carrier, sub-frame, etc.) of at least one layer of resource blocks with the same time and frequency resources. As shown in Fig.8, the UE 800 may include a transceiver unit 801 and a demodulation unit 802. The transceiver unit 801 receives the resource blocks from the transmission point device. The demodulation unit 802 detects the resource blocks in time domain and/or frequency domain to obtain the RS signals, wherein the signals are scrambled by a scrambling sequence initialized by a random seed generated based on a UE specific ID. As described previously with reference to the transmission point device 700, a random seed for initializing a scrambling sequence for RS signals such as DMRS may be generated based on a UE specific ID, such as c-RNTI as shown in the equation (2). That is, according to the present embodiment, the random seed may be generated from the equation (2). It should be noted that the equation (2) is only exemplary and the UE specific ID is not limited to c-RNTI, instead, it may be IMSI or other UE specific IDs which are not listed in the present disclosure.

The UE 800 according to the present disclosure may further include a CPU (Central Processing Unit) 810 for executing related programs to process various data and control operations of respective units in the UE 800, a ROM (Read Only Memory) 813 for storing various programs required for performing various process and control by the CPU 810, a RAM (Random Access Memory) 815 for storing intermediate data temporarily produced in the procedure of process and control by the CPU 810, and/or a I/O unit 817 for inputting or outputting various programs, data and so on. The above transceiver unit 801 , demodulation unit 802, CPU 810, ROM 813, RAM 815 and/or I/O unit 817 etc. may be interconnected via data and/or command bus 820 and transfer signals between one another.

Respective units as described above do not limit the scope of the present disclosure. According to one embodiment of the disclosure, the function of any of the above transceiver unit 801 and demodulation unit 802 may also be implemented by functional software in combination with the above CPU 810, ROM 813, RAM 815 and/or I/O unit 817 etc. According to the present embodiment, by generating random seeds for initializing scrambling sequences for the RS signals based on the UE specific IDs, the conflict requirements on DMRS random seed for the JT scenario and the non-CoMP scenario as shown in Fig.4 are solved, that is, the identical DMRS from multiple transmission points are guaranteed for the JT scenarios while different DMRSs from adjacent transmission points are guaranteed for the non-CoMP scenarios.

(Second Embodiment)

Comparing the equation (2) brought forward in the first embodiment and the equation (1 ) for DMRS random seed generation in release-10, it is found that the random seeds generated from the equation (2) may collide with the random seeds generated from the equation (1 ), because the range of the parameter n_RNTI in the equation (2) is 0~2 ¹⁶ -1 . Considering a case where the random seeds generated from the equation (1 ) are assigned for release-10 UEs while the random seeds generated from the equation (2) are assigned for release-1 1 UEs, Such collision may produce problems if release-10 UEs with the random seeds generated from the equation (1 ) and release-1 1 UEs with the random seeds generated from the equation (2) coexist.

To resolve the above collision problem, equation (3) gives one exemplary improvement on the equation (2) in the first embodiment as follows

c _imt = {[n _s /2} + \)- {2*Max+\)- 2 ¹⁶ + (n _RNTI + 2) (3)

Where Max = Maxim _value(ce 11 _id) , representing the maximum value of transmission point IDs, and parameters ¾ _η¾ , n _s and n_RNTI are the same as those in the equation (2). Comparing the equation (3) with the equation (1 ), it is easy to find that since the parameter Max in the equation (3) corresponds to the maximum value of celljds, Max≥cell_id and accordingly 2*Max+l≥2cell_id+ \ , such that

(k /2j+l)- (2*Mzx+l)- 2 ¹⁶ ≥(ln _s /2}+\) - (2cell_id +\) - 2 ¹⁶ . Furthermore, the parameter SCID in the equation (1 ) is commonly set as 0 or 1 , so that SCID < 2 . Therefore, ([n _s /2}+\)- {2*Max+ \)- 2 ¹⁶ + 2 > (ln _s /2}+\) - (2cell_id + \) - 2 ¹⁶ + SCID . Thus, it is out of question that the random seeds generated from the equation (3) are always larger than release-10 DMRS random seeds generated from the equation (1 ). Using the random seed generation equation (3), the above random seed collision problem can be solved. Note that the equation (3) is only one exemplary improvement on the equation (2) and resolution of the above random seed collision problem is not limited thereto. For example, the constant "2" in the equation (3) is a critical value and can be replaced by an arbitrary number larger than 2. Thereby, according to the present embodiment, for a transmission point device (for example, 700) or a UE (for example, 800), the random seed may be generated from the equation (3). According to the present embodiment, by improving the UE specific random seed generation equation (2) of the second embodiment, collision between the UE specific random seeds and release-10 random seeds can be avoided while the conflict requirements on DMRS random seeds for the JT scenario and the non-CoMP scenario as shown in Fig.4 is solved.

(Third Embodiment)

As described before, the blind detection of DMRS at a receiver side can help an UE to estimate the interference in MU-MIMO operation. However, if the equation (2) or (3) is used to generate DMRS random seeds, the UE may not be able to perform the blind detection, because there are too many possibilities for the UE specific random seeds or the blind detection space is too large in this case. For example, since there are 2 ¹⁶ possibilities for the value of n_RNTI in both the equation (2) and the equation (3) as discussed above, there are 2 ¹⁶ possibilities for random seeds generated from the equation (2) or (3), which results in much more dimensions of DMRS than those of Fig. 6 using the release-10 DMRS random seed generation equation (1 ). It is difficult to perform the blind detection of DMRS in a case of too many dimensions of DMRS. Orthogonality between MU-MIMO DMRS ports is another concern for the equation (2) and the equation (3). As shown in Fig.5, there are two UEs, i.e. UE1 and UE2, in the MU-MIMO case. It is assumed that UE1 is assigned with DMRS port 7 (OCC [1 , 1 ]) and UE2 is assigned with DMRS port 8 (OCC [1 ,-1 ]) and that UE1 and UE2 are both configured with UE specific random seeds generated from the equation (2) or (3). Therefore, it is found that two different sequences are scrambled to the two orthogonal DMRS ports (the ports 7 and 8) respectively as illustrated in Fig. 9. Fig.9 is a schematic diagram showing an example of MU-MIMO DMRSs multiplexed. In Fig.9, the port 7 corresponding to OCC [1 , 1 ] is scrambled by the scrambling sequence [A1 , B1 ...] while the port 8 corresponding to OCC [1 , -1 ] is scrambled by the scrambling sequence [C1 , D1 ...]. The two scrambling sequences are initialized respectively by two different random seeds generated from the above equation (2) or (3) based on their respective UE specific IDs. Here, if (A1 *)C1 +(B1*)D1=0 or [A1 ,B1 ] _L[C1 ,D1 ], the orthogonality between the two DMRS ports is destroyed. Therefore, in such a MU-MIMO case, to keep the DMRS orthogonality between MU UEs, it is necessary to use the same scrambling sequence for two MU UEs if they are assigned with orthogonal DMRS ports (for example, the port 7 and the port 8).

Considering that the release-10 DMRS random seed design enables blind detection as discussed above with reference to Fig.5 and Fig.6, the basic idea of the present embodiment is to switch between the release-10 DMRS random seeds as generated from the equation (1 ) and the UE specific DMRS random seeds as generated from the equation (3) in order to resolve the above two problems encountered in a case of generating DMRS random seeds based on UE specific IDs. Specifically, when UEs are in MU-MIMO operation, the system configures the UEs with the release-10 DMRS random seeds as generated from the release-10 random seed generation equation (1 ); otherwise, the UEs are configured with the UE specific random seeds as generated from the equation (3).

The advantage of such a switch is that: when the UEs are in MU operation, the release- 10 random seeds can enable the blind detection and keep the orthogonality between them; when the UEs are not in MU operation, the UE specific random seeds can satisfy the conflict requirements for both JT and non-CoMP operations.

Fig.10 is a block diagram showing a transmission point device according to the third embodiment of the present disclosure. The transmission point device 1000 according to the third embodiment of the present disclosure is used for communicating with a UE in a communication system. Similarly to the transmission point device 700 of the first embodiment, the transmission point device 1000 transmits, to a UE, RS signals which are assigned on predetermined locations (radio resource, which means the time and/or frequency resource such as sub-carrier, sub-frame, etc.) of at least one layer of resource blocks with the same time and frequency resources. As shown in Fig.10, the transmission point device 1000 may include a selection unit 1001 , an initialization unit 1002, a scrambling unit 1003, and a transceiver unit 1004. The selection unit 1001 selects a random seed from a first random seed generated based on a transmission point ID and a second random seed generated based on a UE specific ID. The initialization unit 1002 initializes a scrambling sequence by the random seed selected in the selection unit 1001. The scrambling unit 1003 scrambles the signals with the scrambling sequence initialized in the initialization unit 1002. The transceiver unit 1004 transmits the resource block with the signals scrambled in the scrambling unit 1003 to the UE. It should be noted that the RS signals here can be any kinds of RS signals such as DMRS and the like.

The transmission point device 1000 according to the present disclosure may further include a CPU 1010, a ROM 1013, a RAM 1015 and/or I/O unit 1017, all of which are the same as those in the transmission point device 700 of the first embodiment. For the sake of simplicity, the description of their functions is omitted here. Also, the above selection unit 1001 , initialization unit 1002, scrambling unit 1003, transceiver unit 1004, CPU 1010, ROM 1013, RAM 1015 and/or I/O unit 1017 etc. may be interconnected via data and/or command bus 1020 and transfer signals between one another.

Respective units as described above do not limit the scope of the present disclosure. According to one embodiment of the disclosure, the function of any of the above selection unit 1001 , initialization unit 1002, scrambling unit 1003 and transceiver unit 1004 may also be implemented by functional software in combination with the above CPU 1010, ROM 1013, RAM 1015 and/or I/O unit 1017 etc.

According to the present embodiment, the UE shown in Fig.8 may also receive from the transmission point device 1000 the resource blocks, and obtain the signals which are scrambled by a scrambling sequence initialized by a random seed selected from a first random seed generated based on a transmission point ID and a second random seed generated based on a UE specific ID.

To implement the switch between the release-10 DMRS random seeds and the UE specific DMRS random seeds, there should be a signaling to notify the UEs about the switch. One simple way is to add one bit signaling flag in current PHY (phisical) signaling for the switch. It should be noted that a way of notifying the UEs of the switch is not limited to the way as described above.

According to the present embodiment, although not shown in Fig.10, the transmission point device 1000 may also include a notification unit which notifies the user equipment of the switch between (selection of) the first random seed and the second random seed by adding one bit signaling as a switch flag. The first random seed may be generated from the equation (1 ). The second random seed is different from the first random seed. The second random seed may be generated from the equation (3).

According to the present embodiment, although not shown in Fig.8, the transceiver unit 802 in the user equipment 800 may also receive a message which indicates the selection of the first random seed and the second random seed with one bit signaling as a switch flag, in which the first random seed may be generated from the equation (1 ), the second random seed is different from the first random seed, and the second random seed may be generated from the equation (3).

According to the present embodiment, by switching between the release-10 DMRS random seeds and the UE specific DMRS random seeds, the blind detection can be enabled and the orthogonality between the UEs can be kept in MU operation, while the conflict requirements for both JT and non-CoMP operations can be solved in non-MU operation.

(Fourth Embodiment) The present embodiment focuses on how to notify the UEs of the selection of the release-10 DMRS random seeds and the UE specific DMRS random seeds.

Fig.11 shows a table for notifying the UEs of DMRS ports and DMRS random seeds in the release-10 as defined in TS 36.212. As shown in Fig.11 , the table is divided into two parts, and the left part corresponds to one codeword case while the right part corresponds to a case of two codewords. In the left part (the one codeword case), the left column gives eight values 0-7 in the one codeword and the right column represents messages indicated by the values. Except that the value 7 is reserved, the other seven values 0-6 indicate different combinations of DMRS ports and DMRS random seeds respectively. Specifically, the value 0 indicates a case of one layer transmission with the port 7 and SCID=0; value 1 indicates a case of one layer transmission with the port 7 and SCID=1 ; the value 2 indicates a case of one layer transmission with the port 8 and SCID=0; value 3 indicates a case of one layer transmission with the port 8 and SCID=1 ; the value 4 indicates a case of two layer transmission with the ports 7-8 and SCID=0; the value 5 indicates a case of three layer transmission with the ports 7-9 and SCID=0; and the value 6 indicates a case of four layer transmission with the ports 7-10 and SCID=0. The right part (the case of two codewords) of the table in Fig.11 is similar with the left part. That is, eight values 0-7 in the two codeword indicate respectively eight different combinations of DMRS ports and DMRS random seeds respectively. Specifically, the value 0 indicates a case of two layer transmission with the ports 7-8 and SCID=0; value 1 indicates a case of two layer transmission with the ports 7-8 and SCID=1 ; the value 2 indicates a case of three layer transmission with the ports 7-9 and SCID=0; value 3 indicates a case of four layer transmission with the ports 7-10 and SCID=0; the value 4 indicates a case of five layer transmission with the ports 7-11 and SCID=0; the value 5 indicates a case of six layer transmission with the ports 7-12 and SCID=0; the value 6 indicates a case of seven layer transmission with the ports 7-13 and SCID=0; and the value 7 indicates a case of eight layer transmission with the ports 7-14 and SCID=0. On PHY signaling, different values are transmitted on the air interface. A UE receives different values and interprets the meanings of the values according to the table of Fig.11 .

From Fig.11 , it is found that SCID equals 0 in most of the cases, that is, the cases of the values 0, 2 and 4-6 in the left part corresponding to the one codeword and the cases of the values 0 and 2-7 in the right part corresponding to the two codewords, which gives a hint that the SCID may be used as an implicit signaling to notify the UEs of the random seed selection. Fig.12 shows a table for notifying the UEs of the selection of the release-10 random seeds and the UE specific random seeds according to the fourth embodiment of the present disclosure. In Fig.12, 8 values are used to indicate release-11 messages in both cases of one codeword and two codewords. By comparing the table of Fig.12 and the table of Fig.11 , it is found that "SCID=0" in Fig.11 is replaced by "UE specific seed" (UE specific random seed) in release-11 message in Fig.12, and "SCID=1 " in Fig.11 is replaced by "rel-10 seed (SCID=0)" (release-10 random seed) in Fig.12. Here, "rel-10 seed (SCID=0)" represents the following equation (4) which is obtained from the equation (1 ) with SCID being set as 0. c _imt = (L« _s / 2 j+ l ). (2N - ^u + 1 2 ¹⁶ (4)

Wherein, the parameter N ^∞u is equivalent to the parameter celljd in the equation (1 ), representing the value of a transmission point ID. "UE specific seed" in Fig.12 means random seeds generated from the equation (3) based on the UE specific IDs. The table shown in Fig.12 uses "SCID" in the table of Fig.11 as an implicit signaling to notify the UEs of the selection of the release-10 random seeds and the UE specific random seeds. That is, when SCID in Fig.11 is 0, it indicates to the selection of the UE specific random seed; when SCID in Fig.11 is 1 , it indicates the selection of the release-10 random seed as generated from the equation (4). Therefore, according to the present embodiment, by using SCID as a switch flag, the UEs can be notified of the switch between (selection of) the release-10 random seeds and the UE specific random seeds through the current PHY signaling without adding one bit signaling flag. It should be noted that the table shown in Fig.12 is only one example. It is easy to see that if the relationship between the "value" and the "message" in the table of Fig.12 is re-ordered, it has the same effects as before. But after re-ordering, the "SCID" can not be interpreted as a switch flag. (Fifth Embodiment)

It should be noted that the release-10 DMRS random seed has two possibilities, that is, SCID=0 (the equation (4)) and SCID=1. However, in the table in Fig.12 of the fourth embodiment, when it is switched to the release-10 DMRS random seed (rel-10 seed), only the SCID=0 case is retained. It is found with reference to Fig.6 that if the blind detection is enabled in this case, combinations of only SCID=0 case and two OCCs ([1 , 1 ] and [1 , -1 ]) result in only two dimensions of the blind detection. However, the release-10 supports four dimensions of the blind detection in fact.

In the present embodiment, in order to overcome the above constraint on the dimensions of the blind detection in the table of Fig.12, the table defined in TS 36.212 (the table of Fig.11 ) may be modified instead of introducing a new bit of switch flag to notify the UE of the RS random seed switching.

The present embodiment starts from analysis of the table in Fig.12. First, it is found that the value 7 in one codeword case is a reserved value. Second, it is found that port 7 (OCC [1 , 1 ]) and port 8 (OCC [1 ,-1 ]) can both support the UE specific random seeds. Furthermore, for non-MU operation (including JT operation and non-CoMP operation), the use of UE specific random seeds is enough as described in the first and the second embodiments; for MU operation, DMRS random seed is switched to the release-10 random seed case. Therefore, it can be concluded that one of ports 7 and 8 is configured with the UE specific random seed is enough.

Based on the above analysis, the basic idea of the present embodiment is: 1 ) DMRS random seeds for one layer transmission is the same as those in the release-10 for the MU scenario; 2) the reserved value 7 in the table for current signaling in Fig.11 is utilized; 3) one of port 7 or port 8 (instead of both port 7 and port 8) is configured with the UE specific random seed for the non-MU scenario. Fig.13 shows a table for notifying the UEs of the switch between (selection of) the release-10 random seeds and the UE specific random seeds according to the fifth embodiment of the present disclosure. The table shown in Fig.13 is an improvement of the table shown in Fig.12. Since only the left part (the one codeword case) of the table in Fig.12 is modified in the present embodiment while the right part (the case of two codewords) remains unchanged, for sake of clarity, only the modified left part is shown in Fig.13. In Fig.13, for MU operation, the release-10 random seeds are normal release-10 random seeds as generated from the equation (1 ). That is, the messages corresponding to values 0-3 are the same as those in the table of Fig.11. Thereby, four dimensions of blind detection are assured. The messages corresponding to values 4-6 in Fig.13 are the same as those in the table of Fig.12, wherein the UE specific random seed is the random seed generated from the equation (3). The value 7 which is reserved in Fig.11 and Fig.12 indicates the case of one layer transmission with port 7 and the UE specific seed in Fig.12. It is seen that because of using the reserved value and configuring just one port (for example, port 7) with the UE specific random seed for rank 1 transmission, it is possible to retain the normal release-10 random seeds in the table shown in Fig.13. Here, it is noted that the value 7 may indicate the case of one layer transmission with port 8 and the UE specific seed, alternatively.

According to the present embodiment, the MU blind detection space is the same as that in release-10 while there is no need to introduce a new signaling bit to notify the UEs of the DMRS random seed switch. It is noted that the table of Fig.13 is only one example, and re-ordering the relationship between the "value" and the "message" in the table has the same effects as described above. Furthermore, it will be appreciated by those skilled in the art that it is also possible to retain only one value of "0" or "2" in the table of Fig.12 in the sense that configuring one port (port 7 or 8) with the UE specific random seed for rank 1 transmission of the MU scenario is sufficient. Specifically, if value 0 is retained, value 1 - 3 and 7 may be used to indicate respectively four combinations of different ports and different release-10 random seeds with respect to one layer transmission. Similarly, if value 2 is retained, value 0, 1 , 3 and 7 may be used to indicate respectively four combinations of different ports and different release-10 random seeds with respect to one layer transmission.

(Sixth Embodiment)

The aforesaid first to fifth embodiments all focus on downlink DMRS cases. In fact, similar problem also occurs on uplink DMRS cases. For example, in UL (uplink) DMRS of PUSCH (Physical Uplink Shared Channel) case, the scrambling sequences are initialized by random seeds based on transmission point IDs. If adjacent transmission points have the same transmission point ID, DMRSs of PUSCH among adjacent transmission points may interfere with each other. In that case, using UE specific random seeds which are based on the UE specific IDs such as n_RNTI is better than using transmission point specific random seeds which are based on for example transmission point IDs. According to the present embodiment, uplink RS signals may be scrambled by a scrambling sequence initialized by a random seed generated based on a UE specific ID.

According to the present embodiment, uplink RS signals may also be scrambled by a scrambling sequence initialized by a random seed which is selected from a first random seed generated based on a transmission point specific ID and a second random generated based on a UE specific ID. (Seventh Embodiment)

The aforesaid first to sixth embodiments all focus on the RS (for example, DMRS) design. In fact, scrambling is also applied to data channels, such as PDSCH (Physical Downlink Shared Channel) or PUSCH, and control channels, such as PDCCH (Physical Downlink Control Channel) or PUCCH (Physical Uplink Control Channel). A scrambling sequence initialized by a random seed is scrambled to a data or control channel to randomize the potential ICI among cells or transmission points. Transmission point IDs are also involved in the random seed generation. Therefore, if adjacent cells or transmission points have different transmission point IDs, the JT operation will encounter problems as described before. In this case, using the UE specific random seeds which is based on the UE specific IDs to initialize the scrambling sequences is also the solution.

According to the present embodiment, for a transmission point device (for example, 700, 1000) or a UE (for example, 800), the signals may be one of RSs, control signals for control channels, and data signals for data channels. That is, according to the present embodiment, signals, either control signals for control channels or data signals for data channels, may be scrambled by a scrambling sequence initialized by a random seed generated based on a UE specific ID, or according to the present embodiment, signals, either control signals for control channels or data signals for data channels, may also be scrambled by a scrambling sequence initialized by a random seed which is selected from a first random seed generated based on a transmission point specific ID and a second random generated based on a UE specific ID.

(Eighth Embodiment)

In LTE (release-8, 9) and LTE-A (release-10), the downlink control channel (PDCCH) is based on CRS (Control Reference Signal) which is used as the RS for demodulation, and CRS is transmission point specific without precoding. However, for release-11 or latter release, it is likely that the PDCCH is enhanced to E-PDCCH (Enhanced PDCCH) by utilizing DMRS as the reference signal to demodulate. In this case, the idea of the first to fifth embodiment can also be applied to DMRS based E-PDCCH: 1 ) DMRS random seed can be generated based on a UE specific ID; 2) The DMRS random seed can be switched between a UE specific random seed and a transmission point specific random seed (such as release-10 random seed).

In addition to the reasons mentioned before, there is another advantage of generating a random seed for DMRS of E-PDCCH based on a UE specific ID: when a UE detects E- PDCCH, the UE is unaware of the potential DMRS configurations because E-PDCCH is a control channel. Thus, if E-PDCCH uses the release-10 DMRS random seed, the UE needs at least to "guess" whether it uses SCID=0 or 1. However, if E-PDCCH uses a UE specific DMRS random seed, the UE knows the DMRS random seed on detecting the E-PDCCH since the UE specific ID such as c-RNTI has already been assigned to the UE at this stage.

(Ninth Embodiment)

The first to eighth embodiments as described above all use a random seed generated based on a UE specific ID to initialize the scrambling sequence for scrambling signals. However, it is noted that the ID on which a random seed is generated is not limited to the UE specific ID. It is also possible to generate the random seed based on a common ID. As an example, equation (5) is used for generating the random seed for initializing a scrambling sequence for signals based on a common ID as follows.

c _mit = {[n _s /2} + \)- {2common_id + \)- 2 ¹⁶ (5)

Wherein, C represents the random seed, n _s represents the slot number, and commonjd represents the common ID.

Comparing the equation (5) with the equation (1 ), it is found that the difference between two equations is that the celljd in the equation (1 ) is replaced by the commonjd in the equation (5) and the SCID is not involved in the equation (5). For the equation (1 ), a UE knows the celljd through a transmission point specific way, i.e, a broadcasting channel. Similarly, for the equation (5), the commonjd can be assigned by a transmission point device and notified to the UE by a UE specific signaling. By using the commonjd, the random seed requirements including the same random seed in JT operation and different random seeds in non-CoMP operation, as shown in Fig.4, can be satisfied through the transmission points assigning the same or different commonjd to the UE(s) respectively. However, in the MU operation, it is likely that a release-11 UE and a release-10 UE may coexist. In this case, if the release-11 UE uses the random seed generated by the equation (5), then the release-10 UE can not take blind detection for MU interference of release-11 UEs. To solve this problem, the idea of the third embodiment as described above can also be used in the present embodiment. That is, for the MU operation, release-10 random seeds as generated by the equation (1 ) based on transmission point IDs are used to initialize the scrambling sequences for scrambling signals. In other cases such as JT operation and non-CoMP operation, random seeds generated by the equation (5) are used. According to the present embodiment, a transmission point device (for example, 1000) may further include a notification unit which notifies the common ID to the UE by UE specific signaling. The second random seed is generated from the equation (5) including the common ID. According to the present embodiment, in a UE (for example, 800), the transceiver unit may further receive UE specific signaling which indicates the common ID from a transmission point. The second random seed is generated from the equation (5) including the common ID. (Tenth Embodiment) Fig.14 is a diagram showing a flow chart of a method of scrambling signals according to the tenth embodiment of the present disclosure.

As shown in Fig.14, the method 1400 according to the tenth embodiment of the present disclosure is used for scrambling signals assigned on predetermined radio resources of at least one layer of resource blocks with the same time and frequency resources. In the step S1401 , a random seed is generated based on a UE specific ID. In the step S1402, a scrambling sequence is initialized by the random seed. In the step S1403, the signals are scrambled with the initialized scrambling sequence.

According to the present embodiment, the above step S1401 can be executed by the random seed generation unit 701 , the above step S1402 can be executed by the initiation unit 702, and the above step S1403 can be executed by the scrambling unit 703.

According to the present embodiment, the user equipment specific ID may be a global user equipment specific identification number.

According to the present embodiment, the user equipment specific ID may be International Mobile Subscriber Identification Number.

According to the present embodiment, the user equipment specific ID may be a user equipment specific ID assigned to a user equipment when the user equipment accesses to a LTE network.

According to the present embodiment, the user equipment specific ID may be c-RNTI.

According to the present embodiment, although not shown in Fig.14, the method 1400 may further include a step of generating the random seed based on the equation (2). According to the present embodiment, although not shown in Fig.14, the method 1400 may further include a step of generating the random seed based on the equation (3).

According to the present embodiment, the signals may be one of reference signals, control signals for control channels, and data signals for data channels.

According to the present embodiment, the signals may be Demodulation Reference Signals. According to the present embodiment, although not shown in Fig.14, the method 1400 may further include a step of transmitting the resource blocks with the scrambled signals from a transmission point to a user equipment or from the user equipment to the transmission point. This step may be executed by the transceiver unit 704 of the transmission point device 700 and the transceiver unit 801 of the UE 800.

According to the present embodiment, by generating random seeds for initializing the scrambling sequences for signals based on the UE specific IDs, the conflict requirements on random seeds for the JT scenario and the non-CoMP scenario are solved.

(Eleventh Embodiment)

Fig.15 is a diagram showing a flow chart of a method of scrambling signals according to the eleventh embodiment of the present disclosure. As shown in Fig.15, the method 1500 according to the present embodiment is used for scrambling signals assigned on predetermined radio resources of at least one layer of resource blocks with the same time and frequency resources. In the step S1501 , a random seed is selected from a first random seed generated based on a transmission point ID and a second random seed. In the step S1502, a scrambling sequence is initialized by the selected random seed. In the step S1503, the signals are scrambled with the initialized scrambling sequence.

According to the present embodiment, the above step S1501 can be executed by the selection unit 1001 , the above step S1502 can be executed by the initiation unit 1002, and the above step S1503 can be executed by the scrambling unit 1003.

According to the present embodiment, the second random seed may be generated based on a common ID assigned by a transmission point.

According to the present embodiment, although not shown in Fig.15, the method 1500 may further include a step of notifying the common ID to a user equipment by user equipment specific signaling. This step may be executed by a notification unit (not shown in Fig.10) of the transmission point device 1000.

According to the present embodiment, the second random seed may be generated from the equation (5).

According to the present embodiment, the second random seed may be generated based on a user equipment specific ID.

According to the present embodiment, the method 1500 may further include a step of notifying a receiver side of the selection of the first random seed and the second random seed by adding one bit signaling as a switch flag. This step may be executed by a notification unit (not shown in Fig.10) of the transmission point device 1000.

According to the present embodiment, the method 1500 may further include a step of notifying a receiver side of the selection of the first random seed and the second random seed by using signaling set with one codeword, wherein, seven values in the one codeword respectively indicate the following seven cases: one layer of signals configured with a first port and the second random seed; one layer of signals configured with the first port and the first random seed; one layer of signals configured with a second port and the second random seed; one layer of signals configured with the second port and the first random seed; two layers of signals configured with the first and the second ports and the second random seed; three layers of signals configured with the first, the second and a third ports and the second random seed; and four layers of signals configured with the first to the third ports and a fourth port and the second random seed. This step may be executed by a notification unit (not shown in Fig.10) of the transmission point device 1000.

According to the present embodiment, the method 1500 may further include a step of notifying a receiver side of the selection of the first random seed and the second random seed by using signaling set with two codewords, wherein, eight values in the two codewords respectively indicate the following eight cases: two layers of signals configured with the first and the second ports and the second random seed; two layers of signals configured with the first and the second ports and the first random seed; three layers of signals configured with the first, the second and the third ports and the second random seed; and four layers of signals configured with the first to the fourth ports and the second random seed; five layers of signals configured with the first to the fourth ports and a fifth port and the second random seed; six layers of signals configured with the first to the fifth ports and a sixth port and the second random seed; seven layers of signals configured with the first to the sixth ports and a seventh port and the second random seed; and eight layers of signals configured with the first to the seventh ports and a eighth port and the second random seed. This step may be executed by a notification unit (not shown in Fig.10) of the transmission point device 1000.

According to the present embodiment, the first random seed is generated from the equation (1 ). According to the present embodiment, the method 1500 may further include a step of notifying a receiver side of the selection of the first random seed and the second random seed by using signaling set with one codeword, wherein, eight values in the one codeword respectively indicate the following eight cases: one layer of signals configured with a first port and the first random seed with SCID=0; one layer of signals configured with the first port and the first random seed with SCID=1 ; one layer of signals configured with a second port and the first random seed with SCID=0; one layer of signals configured with the second port and the first random seed with SCID=1 ; two layers of signals configured with the first and the second ports and the second random seed; three layers of signals configured with the first, the second and a third ports and the second random seed; four layers of signals configured with the first to the third ports and a fourth port and the second random seed; and one layer of signals configured with the first port or the second port and the second random seed. This step may be executed by a notification unit (not shown in Fig.10) of the transmission point device 1000.

According to the present embodiment, the second random seed is different from the first random seed. According to the present embodiment, the second random seed is generated from the equation (3).

According to the present embodiment, the signals are one of reference signals, control signals for control channels, and data signals for data channels.

According to the present embodiment, the method 1500 may further include a step of transmitting the resource blocks with the scrambled signals from a transmission point to a user equipment or from the user equipment to the transmission point. This step may be executed by the transceiver unit 1004 of the transmission point device 1000 and the transceiver unit 801 of the UE 800. According to the present embodiment, by switching between transmission point specific random seeds and UE specific random seeds or random seeds generated based on common IDs assigned by transmission points, the blind detection can be enabled and the orthogonality between UEs can be kept in MU operation, while the conflict requirements for both JT and non-CoMP operations can be solved in non-MU operation.

The foregoing detailed description has set forth various embodiments of the devices and/or processes via the use of block diagrams, flowcharts, and/or examples. Insofar as such block diagrams, flowcharts, and/or examples contain one or more functions and/or operations, it will be understood by those skilled in the art that each function and/or operation within such block diagrams, flowcharts, or examples can be implemented, individually and/or collectively, by a wide range of hardware, software, firmware, or virtually any combination thereof. In one embodiment, several portions of the subject matter described herein may be implemented via Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), digital signal processors (DSPs), or other integrated formats. However, those skilled in the art will recognize that some aspects of the embodiments disclosed herein, in whole or in part, can be equivalently implemented in integrated circuits, as one or more computer programs running on one or more computers (e.g., as one or more programs running on one or more computer systems), as one or more programs running on one or more processors (e.g., as one or more programs running on one or more microprocessors), as firmware, or as virtually any combination thereof, and that designing the circuitry and/or writing the code for the software and or firmware would be well within the skill of one of those skilled in the art in light of this disclosure. In addition, those skilled in the art will appreciate that the mechanisms of the subject matter described herein are capable of being distributed as a program product in a variety of forms, and that an illustrative embodiment of the subject matter described herein applies regardless of the particular type of signal bearing medium used to actually carry out the distribution. Examples of a signal bearing medium include, but are not limited to, the following: a recordable type medium such as a floppy disk, a hard disk drive, a Compact Disc (CD), a Digital Video Disk (DVD), a digital tape, a computer memory, etc.; and a transmission type medium such as a digital and/or an analog communication medium (e.g., a fiber optic cable, a waveguide, a wired communications link, a wireless communication link, etc.).

With respect to the use of substantially any plural and/or singular terms herein, those having skills in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.

While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.