Patent Application
20170331600
This application claims priority to Malaysian Patent Application No. PI2016000890 filed on May 16, 2013, and which application is incorporated herein by reference in its entirety.
Embodiments of the present invention, generally relate to long-term evolution (LTE) network, and in particular relate to a method for enhancing robustness of uplink coordinated multi-point procedure in the LTE network.
Communication networks have evolved exponentially over last two decade. In addition to communication, communication networks are delivering data over large distances and driving the information economy. It has been constant endeavor of communication industry to further improve the communication networks and communication technology to deliver data at higher speed, more secure, more efficient, and more robust.
After success of 2G and 3G, focus is now at 4G (i.e., LTE) networks. To cover maximum area, the LTE wireless communication network generally includes a number of evolved nodes of base stations called as eNodeB (or eNB) that support communication for a number of user equipment (UE). A UE communicate with an eNB via a downlink and an uplink. The downlink (DL) refers to communication link from the eNB to the UE, and the uplink (UL) refers to the communication link from the UE to the eNB. As illustrated in
Conventionally, interference issue has been tried to be solved using various methods, however, they suffer from one or other issues. For example, one of such conventional method tries to utilize handover in the wireless network with coordinated multi-point (CoMP) transmission/reception scheme. The CoMP slave (first base station) is able to decode measurement reports sent by a UE destined to the CoMP master (second base station). Also, the CoMP slave or the first base station can send the handover command to the UE via the instruction from the CoMP master or the second base station.
Another conventional method provides a handover method based on an uplink signal, wherein a source base station sends a trigger message to a user equipment to send an uplink signal used for handover. The source base station receives a notification message by one or more other base stations according to detection of the uplink signal and determines a target base station from the one or more other base stations according to the notification message, and performs handover of the user equipment.
Another conventional method, tries to solve power imbalance between a macro cell and a small cell in heterogonous network. The method identifies the uplink boarder between the macro cell and the small cell, triggers a message to UE to send the measurement report about the neighboring cell, the serving cell then decides to whether the neighboring cell should start monitoring the uplink connection quality of the UE and offloads the uplink traffic to the neighbor cell.
Yet another conventional method provides a method of selecting access points for CoMP uplink reception based on evaluating the measurement reports originating from uplink measurements.
All of the conventional methods discuss methods relate to only handover, measurement reporting by the UE, feedback schemes and coordinated cell selection, or even UL monitoring based on SRS. It is possible that sometimes triggering of CoMP procedure may get delayed or even fail to trigger, in these conventional methods. Further, all of the conventional methods described above have not solved issue of interference up to a satisfactory level.
Therefore, there is a need for an improved communication method and system for solving the issue of interference, and enhancing the robustness of CoMP procedure in LTE wireless communication networks.
According to an aspect of the present disclosure, a method for enhancing robustness of uplink coordinated multi-point (UL CoMP) procedure in a long term evolution (LTE) communication network is provided herein. The method includes selecting at least one coordinated cell (112), by a serving cell (111), for uplink (UL) monitoring of a user equipment (113). The method further includes sending at least one UL activate monitoring command message, by the serving cell (111), to the at least one coordinated cell (112). The method further includes receiving an event A3 measurement report by the serving cell (111), from the at least one coordinated cell (111). The method further includes performing UL CoMP procedure, by the serving cell (111), upon receiving the event A3 measurement report.
According to another aspect of the present disclosure, a method for a coordinated cell to perform uplink (UL) monitoring of event A3 measurement report from a user equipment (UE) in a long term evolution (LTE) communication network is provided. The method includes receiving, by the coordinated cell (112), a UL activate monitoring command message from a serving cell (111). Further, the method includes allocating resources for the UL monitoring of the user equipment (113) and forwarding an event A3 measurement report to the serving cell (111). The method further includes deactivating the UL monitoring after receiving of scheduling information from the serving cell (111).
The preceding is a simplified summary to provide an understanding of some aspects of embodiments of the present invention. This summary is neither an extensive nor exhaustive overview of the present invention and its various embodiments. The summary presents selected concepts of the embodiments of the present invention in a simplified form as an introduction to the more detailed description presented below. As will be appreciated, other embodiments of the present invention are possible utilizing, alone or in combination, one or more of the features set forth above or described in detail below.
The above and still further features and advantages of embodiments of the present invention will become apparent upon consideration of the following detailed description of embodiments thereof, especially when taken in conjunction with the accompanying drawings, and wherein:
To facilitate understanding, like reference numerals have been used, where possible, to designate like elements common to the figures.
As used throughout this application, the word “may” is used in a permissive sense (i.e., meaning having the potential to), rather than the mandatory sense (i.e., meaning must). Similarly, the words “include”, “including”, and “includes” mean including but not limited to.
The phrases “at least one”, “one or more”, and “and/or” are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions “at least one of A, B and C”, “at least one of A, B, or C”, “one or more of A, B, and C”, “one or more of A, B, or C” and “A, B, and/or C” means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B and C together.
The term “a” or “an” entity refers to one or more of that entity. As such, the terms “a” (or “an”), “one or more” and “at least one” can be used interchangeably herein. It is also to be noted that the terms “comprising”, “including”, and “having” can be used interchangeably.
The term “automatic” and variations thereof, as used herein, refers to any process or operation done without material human input when the process or operation is performed. However, a process or operation can be automatic, even though performance of the process or operation uses material or immaterial human input, if the input is received before performance of the process or operation. Human input is deemed to be material if such input influences how the process or operation will be performed. Human input that consents to the performance of the process or operation is not deemed to be “material”.
According to an embodiment of the present invention, the serving cell is configured to enable coordinated multi-point (CoMP) procedure to avoid the interference. Those skilled in the art will appreciate that coordinated multi-point (CoMP), being standardized in 3GPP LTE-Advanced networks, allows multi-cell cooperative processing to mitigate inter-cell interference (ICI) and the communication network operates at higher effective signal-to-interference-plus-noise ratios (SINRs). In the uplink, multiple cells may cooperate to improve the reception performance by increasing the number of antenna spatial macro-diversity and subsequently the uplink throughput at the cell edge of the UE is improved. As illustrated in
In an embodiment, as shown in
In an embodiment, following mapping table may be used for the reference signal received power (RSRP) value used in the rsrpResult IE for the event A3 measurement report.
According to an embodiment of the present invention, the PhysCellId IE is a unique physical (PHY) cell identity ranging from 0 to 503 used for isolating the cells in a same coverage area. Those skilled in the art will appreciate that event A3 is cited in 3GPP TS 36.331 standard and is defined as a neighboring cell whose offset is better than the serving cell (101). In an embodiment, the A3 offset, the reporting interval and etc. are determined by the RRC Connection Reconfiguration message 301 sent by the eNB to the UE. RRC Connection Reconfiguration message includes ReportConfigEUTRA information element (IE) with event A3 information event (eventA3 IE).
Further, the serving cell (111) is configured to receive the event A3 measurement reporting (203). The serving cell (111) is further configured to send the scheduling information (204) to the coordinated cell (112). In an embodiment, UL transmission (205) from the UE can be received by both the serving cell (111) and the coordinated cell (112). Subsequently, the coordinated cell (112) sends the coordinated data (206) to the serving cell (111) for joint processing. During the joint processing, the serving cell (111) applies the interference mitigation technique or signal combining technique in PHY layer to optimize the network performance. However, according to an embodiment of the present invention, the triggering of UL CoMP may fail or delay if the event A3 measurement report is lost and not received by the serving cell. Further, for heterogeneous network comprising different coverage cells, such as macro-cells, micro-cells, pico-cells and femto-cells, the probability of the serving cell, usually macro-cell, not receiving the event A3 measurement report is higher due to the power imbalance.
To solve the problem of not receiving of the A3 measurement report, according to an embodiment of the present invention, the serving cell (111) is configured to activate UL monitoring by a coordinated cell (112) and receives the A3 measurement report from the coordinated cell (as illustrated in
Those skilled in the art will appreciate that even if the measurement report (304) is not received by the serving cell (111), the serving cell (111) can still trigger the UL CoMP based on the forwarded measurement report (305) from the coordinated cell (112). In an embodiment, the message exchange between the service cell (111) and the coordinated cell (112) may either utilize X2 interface or S1 interface.
Thus, according to an embodiment of the present invention, a method for enhancing the robustness of UL CoMP is provided. The UE located at cell edge can experience the benefits of UL CoMP as soon as possible by enabling UL measurement for coordinated cell and thus it avoids the serving cell not hearing the measurement report from the UE over the air. In another embodiment, the method further may select also the newly added cells for UL monitoring when the automatic neighbor relation (ANR) procedures have been performed.
As illustrated in
Example of Table containing the Historical Attached UE's Handover Records associated with the Specific Coordinated Cells is shown below:
The foregoing discussion of the present invention has been presented for purposes of illustration and description. It is not intended to limit the present invention to the form or forms disclosed herein. In the foregoing Detailed Description, for example, various features of the present invention are grouped together in one or more embodiments, configurations, or aspects for the purpose of streamlining the disclosure. The features of the embodiments, configurations, or aspects may be combined in alternate embodiments, configurations, or aspects other than those discussed above. This method of disclosure is not to be interpreted as reflecting an intention the present invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment, configuration, or aspect. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of the present invention.
Moreover, though the description of the present invention has included description of one or more embodiments, configurations, or aspects and certain variations and modifications, other variations, combinations, and modifications are within the scope of the present invention, e.g., as may be within the skill and knowledge of those in the art, after understanding the present disclosure. It is intended to obtain rights which include alternative embodiments, configurations, or aspects to the extent permitted, including alternate, interchangeable and/or equivalent structures, functions, ranges or steps to those claimed, whether or not such alternate, interchangeable and/or equivalent structures, functions, ranges or steps are disclosed herein, and without intending to publicly dedicate any patentable subject matter.
| Number | Date | Country | Kind |
|---|---|---|---|
| PI2016000890 | May 2016 | MY | national |
