Uplink broadband allocation in the presence of narrowband interference

Abstract

A method for multiple access scheduling of a shared communication channel divided into multiple resource blocks, the method comprising: Identifying high-interference resource blocks in the shared communication channel; Receiving an allocation request from a user equipment (UE) to allocate resource blocks to the UE in a first portion of the shared communication channel for future data transmissions; determining an error rate that would result from assigning the UE's allocation request to the first portion of the shared communication channel that has one or more of the high-interference resource blocks; Assigning the allocation request to the first portion of the shared communication channel with the one or more high-interference resource blocks if the determined error rate would be lower than an error rate threshold; and Assigning the allocation request to a second portion of the shared communication channel having fewer of the high-interference resource blocks compared to the first portion of the shared communication channel if the determined error rate would be greater than the error rate threshold.

Description

Background of the invention

[0001] Resource scheduling and allocation are an important aspect of wireless cellular networks. The component that performs such scheduling in a base station is often called a "scheduler." Generally speaking, a scheduler can allocate specific portions of a shared communication channel to different user devices or user equipment (UEs). In a shared uplink communication channel in the LTE (Long Term Evolution) communication protocol, these portions are referred to as resource blocks (RBs). Sometimes one or more RBs deal with high levels of interference, for example, from sources of electromagnetic radiation such as television and radio.From US 2014 / 0269545 A1 and US 2011 / 0242990 A1, various embodiments and methods for controlling and scheduling resource allocations to wireless devices in a wireless communication system are already known, wherein an error rate of transmissions is measured based on past time intervals.

[0002] Accordingly, there is a need for improved methods and apparatus for uplink allocation in the presence of narrowband interference. Brief description of the different views of the drawings

[0003] The accompanying figures, in which like reference numerals refer to identical or functionally similar elements throughout the several views, together with the following detailed description, are incorporated in and constitute a part of the specification and further serve to further illustrate embodiments of concepts incorporating the claimed invention and to explain various principles and advantages of those embodiments. Fig. Figure 1 illustrates a prior art mechanism for allocating subframe resources to terminals. Fig. 2 illustrates a communication system including a radio area network (RAN) in accordance with some embodiments. Fig. 3 illustrates a block diagram of an eNodeB base station in accordance with some embodiments. Fig. 4 illustrates an example subframe for LTE uplink communications in accordance with some embodiments. Fig. 5 illustrates a functional block diagram of an eNodeB base station in accordance with some embodiments. Fig. 6 illustrates a method for scheduling a shared communication channel in accordance with some embodiments. Fig. 7A-C illustrate example terminal allocations of a shared communication channel in accordance with some embodiments.

[0004] Those skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help enhance understanding of embodiments of the invention.

[0005] The apparatus and method components have been represented, where appropriate, by conventional symbols in the drawings, showing only those specific details pertinent to an understanding of embodiments of the invention, so as not to obscure the disclosure with details that would be readily apparent to those of ordinary skill in the art, who will have the benefit of the description provided herein. Detailed description of the invention

[0006] Embodiments of the invention include allocating terminals to portions of a shared communication channel with high-interference resource blocks so that data throughput is increased and no data is lost or corrupted beyond a correctable level, for example, by forward error correction (FEC).

[0007] In the following description, it should be noted that a UE is sometimes referred to as a “terminal equipment” or, in a personified manner, as a “user”.

[0008] Fig. 1 illustrates an exemplary subframe 50a of a shared communication channel containing RBs 52. Within subframe 50a, two of the RBs 52 exhibit high interference, namely RBs 54 and 56. In certain currently available systems, a scheduler does not identify or pay attention to the interference and assigns the RBs with high interference levels to UEs for communication. The accuracy of such communication may be affected by the interference. This type of scheduler may be referred to as a "dumb scheduler." An example of scheduling RBs 52 by a dumb scheduler is represented by subframe 50b. As shown, UEs, or users 1-5, are each assigned a non-overlapping portion of adjacent RBs 52. User 2 is assigned a share containing the high-interference RB 54, and user 3 is assigned another share containing the high-interference RB 56.Since the allocations for User 2 and User 3 are relatively small, the high-interference RBs 54 and 56 have a proportionally large impact on the communications of Users 2 and 3, resulting in lost or corrupted data.

[0009] In certain other currently available systems, a scheduler detects RBs that have relatively high levels of interference and avoids using them. In some cases, RBs surrounding the high-interference RBs 54 and 56 are also avoided. These types of schedulers may be called "interference-avoiding schedulers." Avoiding high-interference RBs helps maintain the accuracy of the information or signal from the UE, but reduces the throughput of the shared communication channel. An example of scheduling RBs 52 by an interference-avoiding scheduler is represented by subframe 50c. As shown, each user 1, 2, and 3 is assigned a set or group of RBs. None of the groups of RBs contains any of the high-interference RBs 54 or 56. However, many of the RBs 52 are not allocated (or are avoided) in subframe 50c.Consequently, much of the available channel capacity is unused, and users 4 and 5 are unable to be scheduled in subframe 50c.

[0010] Another approach to managing interference involves using a notch filter to mitigate the interference. When used with an interference-avoiding scheduler, the notch filter influences the scheduler to use high-interference RBs. The notch filter conditions a signal received at the base station to filter out signals at a specific bandwidth (e.g., associated with a high-interference RB). Both interference and desired communication signals at the specific bandwidth are filtered out. As a result, the frequency band associated with an RB will, in many cases, no longer be subject to the interference level that the scheduler uses to identify high-interference RBs. Thus, the scheduler will allocate at least some interference RBs to users.However, the data in these high-interference RBs is filtered out (i.e., lost) by the notch filter, leading to a similar result to the first technology with the dumb scheduler.

[0011] According to one embodiment, the invention is directed to a method for multiple access scheduling of a shared communication channel divided into a plurality of resource blocks. The method includes identifying high-interference resource blocks in the shared communication channel and receiving an allocation request from a terminal or a UE. The method further includes determining an error rate that would result if the UE's allocation request were allocated to a first portion of the shared communication channel having one or more high-interference resource blocks. The method also includes allocating the allocation request to the first portion of the shared communication channel having the one or more high-interference resource blocks if the error rate is less than or equal to an error rate threshold.

[0012] According to another embodiment, a method for multiple access scheduling a shared communication channel divided into a plurality of resource blocks includes: determining a set of candidate UEs for scheduling, each UE corresponding to an allocation request, identifying high-interference resource blocks in the shared communication channel, selecting a first UE from the set of candidate UEs, determining an error rate that would result from assigning the first UE a first portion of the shared communication channel having one or more high-interference resource blocks, and assigning the first UE the first portion of the shared communication channel having one or more high-interference resource blocks if the error rate is less than or equal to an error rate threshold.

[0013] According to yet another embodiment, a base station for wirelessly communicating with UEs over a shared communication channel divided into a plurality of resource blocks includes: a radio unit having a receiver and a transmitter enabling wireless communication with the UEs, and a scheduler implemented on a processor, comprising: a high-interference resource block identifier configured to identify high-interference resource blocks in the shared communication channel, an allocation request handler configured to determine a set of candidate UEs for scheduling, wherein each candidate UE corresponds to a received allocation request, and wherein a first UE is formed from the set of candidate UEs, an allocation error rate calculator configured to determine an error rate that would result therefrom,that the first UE would be assigned a first portion of the shared communication channel having one or more high-interference resource blocks, and a scheduling unit configured to assign the first portion of the shared communication channel having one or more high-interference resource blocks to the first UE if the error rate is less than or equal to an error rate threshold.

[0014] Fig. Figure 2 illustrates a communications system 100 including a radio area network (RAN) 102 in combination with one or more networks 104. In certain examples described herein, the RAN 102 is assumed to implement the LTE communications protocol, although the RAN 102 may implement other communications protocols in other embodiments of the invention. The RAN 102 includes one or more user devices, all of which are referred to herein as user equipment (UE) 106. Each UE 106 may be, for example, a smartphone, a tablet, a PDA ("personal digital assistant"), or other computing device.Such devices typically include, for example, a processor, a memory having software stored therein for execution by the processor, and a wireless communications module including an antenna through which the processor is operable to communicate wirelessly via the RAN 102.

[0015] Each UE 106 is operable to communicate wirelessly with a base station of the RAN 102. In the illustrated example, the base station is an eNodeB (“enhanced NodeB”) 108. The eNodeB 108 includes one or more antennas and processing equipment, as described with reference to Fig. 3. Communication between the UEs 106 and the eNodeB 108 occurs over wireless communication links 110, which may also be referred to as air interfaces 110. A communication link 110 over which data is transmitted from the eNodeB 108 to the UEs 106 is referred to as a downlink, while a communication link 110 over which data is transmitted from the UEs 106 to the eNodeB 108 is known as an uplink. A particular communication link 110 may operate as an uplink, a downlink, or both at a given time, and it may switch between uplink and downlink functionality over time (e.g., frequently). LTE uses different air interface technologies on the downlink and the uplink.Specifically, LTE uses a technology known as OFDMA (Orthogonal Frequency Division Multiple Access) on the downlink, while a technology known as SC-FDMA (Single Carrier Frequency Division Multiple Access) is used on the uplink.

[0016] On the downlink, LTE defines several physical layer data and control channels. The downlink data channels of the physical layer are called PBCH (physical broadcast channel), PDSCH (physical downlink shared channel), and PMCH (physical multicast channel), while the downlink control channels of the physical layer are known as PDCCH (physical downlink control channel), PCFICH (physical control format indicator channel), and PHICH (physical hybrid-ARQ (automatic repeat query) indicator channel). The PDSCH is the primary traffic-carrying channel on the downlink.The PDSCH is used by the eNodeB 108 to transmit downlink transport blocks to various UEs 106 to which the eNodeB 108 provides services.

[0017] On the uplink, LTE defines three physical layer channels, known as PUSCH (physical uplink shared channel), PUCCH (physical uplink control channel), and PRACH (physical random access channel). Generally, the PUSCH is dedicated to carrying user data and some control information; the PUCCH is dedicated to carrying uplink feedback data (e.g., MAC (media access control) uplink feedback data) and requests to be scheduled for uplink user data transmission; and the PRACH is dedicated to purposes such as initial UE access, service requests (i.e., switching from standby to active mode), and uplink synchronization re-establishment.

[0018] Although the eNodeB 108 is part of a fixed radio tower in Fig. As illustrated in Figure 2, the eNodeB 108 may be mounted on a vehicle as part of an IAN (incident area network) (a type of RAN) for tactical or selective deployment.

[0019] The eNodeB 108 communicates with an EPC ("evolved packet core") 114 over a communication link 112. The communication link 112 may include one or more communication devices, modems, accounts, networks, links, switches, bridges, routers, and the like, and it could use wired modes of communication, wireless modes of communication, or both.The EPC 114 includes network entities such as one or more mobility management entities (MMEs), one or more serving gateways (SGWs), one or more packet data network (PDN) gateways (PGWs), one or more home subscriber servers (HSSs), one or more access network discovery and selection functions (ANDSFs), one or more evolved packet data gateways (ePDGs), or a combination thereof. These network entities of the EPC 114 are configured and interconnected in a manner to provide wireless services to the UEs 106 via the eNodeBs 108 and to bridge the wireless services to the networks 104.The network(s) 104 include(s), for example, a PSN (packet switched network) (e.g., the Internet) and a CSN (circuit-switched network) (e.g., the PSTN (Public Switched Telephone Network).

[0020] Fig. Figure 3 illustrates a block diagram of the eNodeB 108. In the illustrated embodiment, the eNodeB 108 includes a baseband unit 150, a radio unit 152, and a bus 154 that provides a communication link between the various components. Although only a single radio unit 152 or a single baseband unit in Fig. 3, the eNodeB 108 may include more than one radio unit 152 and more than one baseband unit 150, and in ratios other than one-to-one. The baseband unit 150 includes a processor 156 and a memory 158. The memory 158 contains operational data for use by the processor 156 and program instructions for execution by the processor 156, thereby enabling the baseband unit 150 to control the radio unit 152 and communicate with the UEs 106 and the EPC 114. Although a single processor 152 and memory 158 are illustrated, the baseband unit 150 may include two or more processors 156 and two or more memories 158 to implement the baseband unit functionality described herein. The radio unit 152 includes an antenna 160, a receiver (Rx) 162 and a transmitter (Tx) 164.The antenna 160, the receiver 162, and the transmitter 164 enable the baseband unit 150 to communicate wirelessly with the UEs 106 over the wireless communication links 110. The receiver 162 and the transmitter 164 may be separate units or part of a transceiver that both receives and transmits data.

[0021] As noted, in an exemplary implementation, the eNodeB 108 and the UEs 106 use SC-FDMA technology for uplink communications. During uplink communications, the wireless communication links 110 are divided into both frequency and time domains. On the LTE uplink, the division of the air interface in the frequency domain takes the form of a single uplink carrier divided into a series of adjacent subcarriers, each having a bandwidth of 15 kilohertz (kHz). The uplink is delimited into successive groups of 12 subcarriers each, and it is these groups, called resource blocks (RBs), that contain the smallest units of the uplink that can be allocated to a given UE 106 in the frequency domain. Thus, in this example, each RB has a bandwidth of 180 kHz and contains 12 subcarriers, each having a bandwidth of 15 kHz.

[0022] In the time domain, the LTE uplink is divided into 10-millisecond (ms) frames, each of which is divided into 10 1-ms subframes. Each subframe represents the smallest unit of uplink that can be allocated to a given UE in the time domain. Thus, the atomistic unit of allocation on the LTE uplink is an RB for a subframe.

[0023] Fig. 4 illustrates an exemplary subframe 200 for LTE uplink communications between UEs 106 and the eNodeB 108. The illustrated subframe 200 includes 50 RBs 202. The first and last RBs 202a are shown as control channels 204, which can be considered, for example, a physical uplink control channel (PUCCH). The intermediate 48 RBs 202b are used as shared communication channels 206, and they can be considered, for example, the shared physical uplink channel (PUSCH), designated to carry user data and some control information. The total number of RBs, the number of RBs designated for PUCCH, and the number of RBs designated for PUSCH are exemplary, and more or fewer RBs can be used in each subframe 200.

[0024] Subframe 200 contains a single instance of narrowband interference 208 located in the middle of the band and at a level of, for example, -80 dBm at the antenna port. In this instance, the RB 202 at which the interference 208 is located would be considered a high-interference RB. The interference 208 may be caused by intentional interference (e.g., jamming) or unintentional interference. Unintentional interference sources may be direct in-band interference sources, such as legacy narrowband P25 devices, including vehicle repeaters, wireless microphones, and broadcast TV signals, among others. Unintentional interference sources may also include IMD (inter-modulation distortion) products between out-of-band sources that fall into the band.In addition, the interference at a given RB, such as interference 208, may include a noise component and an interference component, only a noise component, or only an interference component.

[0025] Fig. Figure 5 illustrates a functional block diagram of the eNodeB 108. The baseband unit 150 and the radio unit 152 are configured to implement the functions of the eNodeB 108 described with reference to Fig. 5. For example, work instructions stored in memory 158, when executed by processor 150, in cooperation with radio unit 152, may perform one or more or all of the functionalities described with reference to the functional block diagram as shown in Fig. 5.

[0026] The eNodeB 108 includes a scheduler 250 that communicates with the UEs 106 and an interference estimator 252. The scheduler 250 receives allocation requests from the UEs 106 and allocates RBs to the UEs 106 to enable orderly communication over a shared communication band, including the various communication links. For uplink communications on the PUSCH, each scheduled UE 106 is assigned to an adjacent set of RBs 202b. In other words, a particular UE 106 in a subframe is not assigned to some RBs 202b at one end of the channel 206, but to some RBs 202b at the opposite end of the channel 206.

[0027] The scheduler 250 includes an error rate provider 254, an allocation request handler 256, a high-interference RB identifier 258, an allocation error rate calculator 260, and a scheduling unit 262. The allocation request handler 256 receives an allocation request from each UE 106 that wishes to transmit data on an uplink channel. The allocation request handler 256 buffers and sorts received allocation requests and selects a set of candidate UEs 106 for scheduling, such as UE S1-5 .

[0028] The interference estimator 252 determines and provides an interference estimate for each of the RBs 202b in the shared communication channel 206. The high-interference RB identifier 258 receives the interference estimates from the interference estimator 252. The high-interference RB identifier 258 then identifies high-interference RBs in the channel 206 based on the received interference estimates. For example, to identify high-interference RBs, the high-interference RB identifier 258 compares the interference estimate for each RB 202b to an interference threshold. If the interference estimate for a particular RB 202b exceeds the interference threshold, the high-interference RB identifier 258 considers the RB to be a high-interference RB.

[0029] The interference threshold for a particular RB may have a value between approximately -110 dBm and -100 dBm per resource block, for example, -100 dBm / RB, -103 dBm / RB, -107 dBm / RB, or -109 dBm / RB. For example, with -100 dBm / RB as the interference threshold, if the interference power level is determined to be greater than -100 dBm / RB (for example, -99 dBm / RB) for a particular RB 202, the RB 202 is considered a high-interference RB. Alternatively, the threshold may be expressed in a relative sense. For example, the threshold may be an interference enhancement of 18 dB relative to a receiver's thermal noise background. Thus, an RB with an interference enhancement greater than 18 dB (for example, 19 dB) would be considered a high-interference RB.Assuming a noise figure level of 3 dB and a noise background of -121 dBm / RB for the eNodeB 108, an interference enhancement threshold of 18 dB / RB would be essentially equivalent to the threshold of -100 dBm / RB. Alternatively, the threshold is expressed as a signal-to-interference level threshold, selected based on the level of the desired signal.

[0030] The allocation error rate calculator 260 receives a candidate UE (e.g., UE1) from the set of candidate UEs from the allocation request handler 256 and receives an indication from the high-interference RB identifier 258 of each of the RBs in the channel 206 identified as having high interference. The allocation error rate calculator 260 then determines a block error rate that would result from allocating the candidate UE a first portion of the channel 206 having one or more high-interference RBs.

[0031] This first share is selected based on the candidate UE's allocation request, where the request specifies the candidate UE's scheduling requirements (e.g., the number of bits to be allocated in the subframe) and the candidate UE's power headroom. In one example, upon selecting the first share, the allocation error rate calculator 260 may first determine a common RB allocation and modulation and coding scheme (MCS) level that would result without considering interference levels. This common RB allocation is selected based on the candidate UE's scheduling requirements and the candidate UE's power headroom. The power headroom influences the MCS level and the number of non-interfered RBs allocated to the UE.Then, the allocation error rate calculator 260 modifies the ordinary RB allocation to arrive at the first proportion by increasing the number of RBs to be allocated, including at least some high-interference RBs, thereby lowering the MCS level.

[0032] The block error rate for a particular assignment depends on one or more of the candidate UE's power transmission level, the number of RBs in the assignment, the number of high-interference RBs in the assignment, and a selected MCS level. The block error rate determined for the candidate UE is sent to the scheduling unit 262.

[0033] The allocation error rate calculator 260 also sends details of the proposed allocation for the candidate UEs to the error rate provider 254. The error rate provider 254, on the other hand, determines an error rate threshold, also referred to as the target block error rate, for the proposed allocation based on the details. The error rate threshold is calculated based on one or more of the power transmission levels of the candidate UEs, the number of RBs in the allocation, the number of high-interference RBs in the allocation, and a selected MCS level. The error rate provider 254 then sends the determined error rate threshold to the scheduling unit 262 directly or via the allocation error rate calculator 260.

[0034] Scheduling unit 262 then compares the determined block error rate for the candidate UE with the error rate threshold. If the determined block error rate is less than or equal to the error rate threshold, scheduling unit 262 allocates the RBs 202b of the first portion of channel 206 to the candidate UE. A certain level of error is desirable in communication systems that support retransmissions, as this results in improved throughput. The allocation of RBs includes sending an identification of the allocated RBs 202b to the candidate UE over a communication link 110.

[0035] If the determined block error rate is greater than the error rate threshold, the scheduling unit 262 does not allocate the first portion of the channel 206 to the candidate UE. Instead, the allocation request handler 256 selects a new candidate UE and provides it to the error rate calculator 260 to restart the scheduling process with the new candidate UE. In other words, the scheduler 250 will allocate the first portion (or another portion) of the channel 206 with one or more high-interference RBs to the new candidate UE if the allocation did not exceed an error rate threshold.To schedule the new candidate UE, a new error rate that would result from assigning the new candidate UE is calculated by the assignment error rate calculator 260, a new error rate threshold may be calculated by the error rate provider 254 for the proposed assignment, and the scheduling unit 262 determines whether to assign RBs 202b based on whether the new error rate threshold is exceeded.

[0036] Scheduler 250 continues to process allocation requests, attempting to first allocate UEs to portions of channel 206 that have high-interference RBs. Once the portions of channel 206 that have high-interference RBs are allocated, and assuming that RBs in channel 206 remain unallocated, the remaining candidate UEs are allocated to portions of channel 206 that do not have high-interference RBs.

[0037] In some embodiments, if the determined block error rate is greater than the error rate threshold, the allocation error rate calculator 260 determines whether the candidate UE's transmission power can be increased and, if so, whether the resulting error rate would then be below the error rate threshold. To do this, the allocation error rate calculator 260 determines the candidate UE's available transmission power surplus, i.e., the difference between the current transmission power and the candidate UE's maximum transmission power. The available transmission power surplus can then be determined from the candidate UE based on information within the allocation request. If transmission power surplus is available, the allocation error rate calculator 260 determines a new error rate that would result if the candidate UE's transmission power were increased.The new error rate is then sent to the scheduling unit 262, which in turn determines whether the error rate would be less than or equal to the error rate threshold. If the error rate is less than or equal to the error rate threshold, the scheduling unit 262 allocates the RBs to the candidate UE and, with the allocation, requests that the candidate UE increase its transmission power by the amount determined by the allocation error rate calculator 260. Alternatively, if the error rate still exceeds the error rate threshold, the scheduler 250 will not allocate any RBs to the candidate UE, and scheduling will proceed as described above.

[0038] Fig. 6 illustrates a method 300 for multiple access scheduling of a shared communication channel divided into multiple RBs (e.g., channel 206), performed by the scheduler 250. In step 302, the scheduler 250 determines a set of candidate UEs for scheduling, for example, using the allocation request handler 256. For example, the allocation request handler 256 may determine the set of candidate UEs by selecting UEs (e.g., UE1, UE2, ... UE N) that have recently sent allocation requests to the scheduler 250. In step 304, the scheduler 250 determines an interference estimate for each of the RBs in the shared uplink communication channel 206, for example, using the output of the interference estimator 252. In step 306, the scheduler 250 identifies high-interference RBs in the shared uplink communication channel 206, for example, using the high-interference RB identifier 258. In step 308, the scheduler 250 selects a yet-to-be-scheduled (unscheduled) UE from the set of candidate UEs, for example, UE1. The scheduler 250 selects a candidate UE based on factors such as a size of the request from UE1, a priority level of the request from UE1, and an amount of time that has elapsed since the request was received by the scheduler 250.In step 310, the scheduler 250 selects a portion of the shared communication channel that has one or more high-interference RBs. Sometimes, this step includes first identifying the number of RBs without a high-interference level that would typically be allocated to UE1 (e.g., "X") and the associated MCS level (e.g., based on the UE's power surplus and a number of bits to be allocated in that subframe). The scheduler 250 then increments this number by one or more RBs (e.g., 2) and selects a neighboring portion of the subframe having a size equal to the increased number of RBs (e.g., X + 2). This selected neighboring portion contains one or more high-interference RBs and is the selected portion of step 310. Likewise, the associated MCS level of the selected portion is set slightly lower than the previously identified MCS level.

[0039] In step 312, the scheduler 250 determines an error rate that would result from assigning the selected candidate UE1 to the selected portion of the channel 206 with one or more high-interference RBs, for example, using the assignment error rate calculator 260. In step 314, the scheduler 250 determines whether the error rate that would result from assigning the assignment request of the selected candidate UE to a first portion of the shared communication channel 260 with one or more high-interference RBs would be below an error rate threshold. If the error rate were lower than the error rate threshold, the scheduler 250 would assign the selected candidate UE to RBs in the first portion of the shared communication channel with one or more high-interference RBs (step 316).

[0040] After assigning UE1 in step 316 or determining that the error rate would exceed the error rate threshold in step 314, the scheduler 250 proceeds to step 318. In step 318, the scheduler determines whether any unscheduled candidate UEs remain (e.g., UE2 - UE N ). If no unscheduled candidate UEs remain, the scheduler 250 has finished scheduling the particular subframe (step 320). If unscheduled candidate UEs remain, the scheduler 250 proceeds to step 322.

[0041] In step 322, the scheduler 250 determines whether any high-interference RBs remain unassigned in the shared communication channel 206. If any RBs remain, the scheduler 250 proceeds to step 308 to select another UE yet to be scheduled from the set of candidate UEs and proceeds through the method 300 as described above, but with the new candidate UE. For example, the scheduler 250 will determine whether to assign UE2 a second portion of the shared communication channel that has high-interference RBs. If the scheduler 250 determines in step 322 that no high-interference RBs remain, the scheduler 250 proceeds to step 324 to assign any remaining unscheduled candidate UEs to the remainder of the shared communication channel 206 that does not have any high-interference RBs.Since the remainder of the shared communication channel 206 does not contain high-interference RBs, the unscheduled candidate UEs are assigned to RBs according to normal scheduling procedures (e.g., based on a priority level of the request, the size of the request, and a time of the request).

[0042] For example, if we assume that unallocated RBs remain after the high-interference RBs are allocated, and that UE1 was not allocated to the first share (or another share with high-interference RBs) because its associated error rate exceeded the error rate threshold, the scheduler 250 allocates UE1 to a third share of the channel that has no identified high-interference RBs in step 324. The third share that has no high-interference RBs has fewer high-interference RBs than the first share of the channel with which UE1 was originally attempted to be allocated.

[0043] Once the rest of the candidate UEs are scheduled or the RBs are assigned to channel 206, the subframe scheduling is completed (step 320), and the assignments are communicated to the UEs (e.g., via wireless communication links 110). Once subframe scheduling is completed and the assignments to the UEs are communicated, the UEs communicate over channel 206 according to the RB allocations by scheduler 250. In other words, the eNodeB 108 receives uplink data from the UEs 106 over channel 206 and forwards the data upstream to the EPC 114 (see Fig. 1 and Fig. 2).

[0044] The Fig. 7A-C illustrate exemplary shared communication channels 400a, 400b, 400c (similar to channel 206) and potential RB allocations for UEs 106 scheduled by scheduler 250. The Fig. 7A illustrates a shared channel 400a with two high-interference RBs 402 and two example UE assignments 404 and 406. The scheduling unit 262 schedules the UE assignment 404 after determining that the error rate for the assignment (as determined by the assignment error rate calculator 206) would not exceed the error rate threshold calculated by the error rate provider 254. If the scheduling unit 262 determines that the error rate for the assignment would not exceed the error rate threshold, the UE assignment 406 is not scheduled. At a later time, the UE assignment 406 may be assigned to a different portion of the shared channel 400a.

[0045] Fig. 7B illustrates a shared channel 400b with four high-interference RBs 410 and two example UE schedules 412 and 414. For schedule 412, scheduling unit 262 allocates UE allocation 416 after determining that the error rate for the allocation would not exceed the error rate threshold calculated by error rate provider 254. For schedule 414, scheduling unit 262 allocates UE allocation 418 to user A after determining that the error rate for the allocation would not exceed the error rate threshold. Scheduling unit 262 then allocates UE allocation 420 to user B after determining that the error rate for the allocation would not exceed the error rate threshold.

[0046] Fig.7C illustrates a shared channel 400c with two high-interference RBs 430 and the scheduling of five UEs to the shared channel 400c. The scheduler 250 may begin with the UE assignment 432 (for user 1) and attempt to schedule a UE assignment 432 to a first portion of the channel 400c that includes one of the high-interference RBs 430. However, the scheduling entity will not schedule the UE assignment 432 for this first portion because the error rate exceeds the error rate threshold. The scheduler may attempt and determine not to schedule the UE assignments 434 (for user 2) and 436 (for user 3) to the portions of the channel with the high-interference RBs 430, again because the error rate for such assignments exceeds the error rate threshold. Thereafter, the scheduler 250 attempts to allocate the UE allocation 438 (for user 4) to a first portion of the shared channel 400c with one of the high interference RBs 430.The allocation of UE allocations 438 occurs because the corresponding error rate is lower than the error rate threshold. The scheduler 250 then attempts to allocate the UE allocation 440 (for user 4) to a second portion of the shared channel 400c with the other high-interference RBs 430. Similarly, the allocation of UE allocations 440 occurs because the corresponding error rate is lower than the error rate threshold. The scheduler 250 then returns to users 1-3 and allocates the associated UE allocations 432, 434, and 436 to the remaining portions of the shared channel 400c.

[0047] Although the above scheduling techniques were primarily described with reference to a shared uplink channel in LTE communications (e.g., PUSCH), the scheduling of user equipment to shares of shared communication channels with high-interference RBs is applicable to other shared communication channels split into RBs, some of which may experience high interference. For example, selective scheduling across high-interference RBs is also applicable to shared downlink channels in LTE, shared downlink channels in communication protocols other than LTE, shared uplink channels other than PUSCH in LTE, shared uplink channels in communication protocols other than LTE, and shared bidirectional channels, among other possibilities.

[0048] In the foregoing specification, specific embodiments have been described. However, it will be apparent to those skilled in the art that various modifications and changes may be made without departing from the spirit of the invention as set forth in the claims below. Accordingly, the specification and figures are to be considered in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the spirit of the present teachings.

[0049] The benefits, advantages, solutions to problems, and any conceivable element that results in any benefit, advantage, or solution occurring or becoming more pronounced are not to be construed as critical, required, or essential features or elements of any or all of the claims. The invention is defined solely by the appended claims, including any amendments made during the pendency of the present application, and all equivalents of such claims as published.

[0050] Furthermore, in this document, relational expressions such as first and second, top and bottom, and the like are intended to be used solely to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms "comprises," "comprising," "has," "having," "include," "containing," "contain," "containing," or any variation thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising, having, including, or containing a list of elements may include not only those elements, but may include other elements not expressly listed or inherent in such processes, methods, articles, or devices. An element that continues with "comprises... a," "has...a", "includes... a", "contains... a", does not, without further qualification, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprise, have, include, or contain the element. The terms "a" and "an" are defined as one or more unless explicitly stated otherwise herein. The terms "substantially", "essentially", "approximately", "about", or any other version thereof have been defined as "being close to" as would be understood by one of ordinary skill in the art, and in one non-limiting embodiment, the term is defined to be within 10%, in another embodiment within 5%, in another embodiment within 1%, and in another embodiment within 0.5%. The term "coupled", as used herein, is defined as "connected," although not necessarily directly and not necessarily mechanically.A device or structure that is "configured" in a particular way is configured in at least that way, but may also be configured in at least one way that is not listed.

[0051] It is desired that some embodiments include one or more generic or specialized processors (or "processing devices"), such as microprocessors, digital signal processors, custom processors, and field programmable gate arrays (FPGAs), and unique stored program instructions (including both software and firmware) that control the one or more processors to, in conjunction with certain non-processor circuitry, implement some, most, or all of the functions of the method and / or apparatus described herein.Alternatively, some or all of the functions can be implemented by a state machine that has no stored program instructions, or in one or more application-specific integrated circuits (ASICs) in which each function, or some combination of certain functions, is implemented as custom logic. Of course, a combination of the two approaches can be used.

[0052] Furthermore, an embodiment may be implemented as a computer-readable storage medium having computer-readable code stored thereon for programming a computer (e.g., including a processor) to perform a method described and claimed herein. Examples of such computer-readable storage media include, but are not limited to, a hard disk, a CD-ROM, an optical storage device, a magnetic storage device, a ROM (Read Only Memory), a PROM (Programmable Read Only Memory), an EPROM (Erasable Programmable Read Only Memory), an EEPROM (Electrically Erasable Programmable Read Only Memory), and a flash memory.Furthermore, it is expected that one skilled in the art, notwithstanding possible considerable effort and a wide range of design choices due, for example, to available time, current technology, and economic considerations, guided by the concepts and principles disclosed herein, will readily be able to generate such software instructions and programs and ICs with minimal experimentation.

[0053] The abstract of the disclosure is provided to allow the reader to quickly appreciate the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the spirit or meaning of the claims. Additionally, it will be appreciated from the foregoing detailed description that various features in various embodiments are grouped together to streamline the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as will be apparent from the following claims, inventive subject matter is found in fewer than all features of a single disclosed embodiment.Thus, the following claims are hereby incorporated into the detailed description, with each claim standing on its own as separately claimed subject matter.

Claims

[1] A method for multiple access scheduling of a shared communication channel divided into a plurality of resource blocks, the method comprising: Identifying high-interference resource blocks in the shared communication channel; Receiving an allocation request from a user equipment (UE) to allocate resource blocks to the UE in a first portion of the shared communication channel for future data transmissions; determining an error rate that would result from assigning the UE's allocation request to the first portion of the shared communication channel that has one or more of the high-interference resource blocks; Assigning the allocation request to the first portion of the shared communication channel with the one or more high-interference resource blocks if the determined error rate would be lower than an error rate threshold; and Assigning the allocation request to a second portion of the shared communication channel having fewer of the high-interference resource blocks compared to the first portion of the shared communication channel if the determined error rate would be greater than the error rate threshold. [2] The method of claim 1, further comprising: Determining an interference estimate for each of the resource blocks in the shared communication channel, wherein identifying high-interference resource blocks in the shared communication channel is based on the determined interference estimate. [3] The method of claim 1 or 2, further comprising: Receiving a second allocation request from a second UE; Determining a second error rate that would result from assigning the second allocation request of the second UE to a third portion of the shared communication channel with one or more high-interference resource blocks; and Assigning the second allocation request to the third portion of the shared communication channel having the one or more high-interference resource blocks if the second error rate is less than or equal to the second error rate threshold. [4] The method of claim 1, wherein the shared communication channel is an uplink channel. [5] The method of claim 1, wherein assigning the allocation request includes sending to the UE: an indication of the first share of the shared communication channel; and a request to increase a power transmission level for the UE for using the first portion of the shared communication channel. [6] The method of claim 1, further comprising: Determining the error rate threshold based on a number of resource blocks of the first portion of the shared communication channel and a modulation and coding scheme proposed for the first portion of the shared communication channel. [7] The method of claim 1, wherein determining the resulting error rate is determined as a function of a power transmission level of the UE and / or a number of resource blocks in the allocation request and / or a number of high interference resource blocks in the first portion of the shared communication channel and / or a selected modulation and coding scheme level. [8] The method of claim 7, wherein determining the resulting error rate is determined as a function of at least the number of resource blocks in the allocation request, the number of high interference resource blocks in the first portion of the shared communication channel, and the selected modulation and coding scheme level. [9] Base station for wirelessly communicating with user equipment (UEs) via a shared communication channel divided into several resource blocks, comprising: a radio unit with a receiver and transmitter, enabling wireless communication with UEs; and a scheduler implemented on a processor, comprising: a high-interference resource block identifier configured to identify high-interference resource blocks in the shared communication channel, an allocation request handler configured to: Determining a set of candidate UEs for scheduling, each candidate UE corresponding to a received allocation request requesting allocation of resource blocks to the candidate UE in the shared communication channel for future data transmissions, and; Selecting a first UE from the set of candidate UEs, an allocation error rate calculator configured to determine an error rate that would result from allocating to the first UE a first portion of the shared communication channel with one or more of the high-interference resource blocks, a scheduling unit configured to assign the first portion of the shared communication channel with the one or more of the high-interference resource blocks to the first UE if the determined error rate is lower than an error rate threshold; and to allocate to the first UE a second portion of the shared communication channel having fewer of the high interference resource blocks compared to the first portion of the shared communication channel if the determined error rate would be greater than the error rate threshold. [10] Base station according to claim 9, further comprising: an interference estimator configured to determine an interference estimate for each of the resource blocks in the shared communication channel, and wherein the high interference resource block identifier is further configured to identify high interference resource blocks in the shared communication channel based on the interference estimate for each of the resource blocks. [11] The base station of claim 9, further comprising an error rate provider configured to provide the error rate threshold to the scheduling unit, wherein the error rate provider determines the error rate threshold based on a number of resource blocks of the first portion of the shared communication channel, and a modulation and coding scheme proposed for the first portion of the shared communication channel. [12] Base station according to claim 9, further comprising: the allocation request handler is further configured to select a second UE from the set of candidate UEs; the allocation error rate calculator is further configured to determine a second error rate that would result from allocating a second portion of the shared communication channel with one or more high-interference resource blocks to the second UE; and the scheduling unit is further configured to allocate the second portion of the shared communication channel with one or more high-interference resource blocks to the second UE if the error rate is less than or equal to the second error rate threshold. [13] The base station of claim 9, wherein the shared communication channel is an uplink channel between the UEs and the radio unit. [14] The base station of claim 9, wherein the allocation error rate calculator is further configured to determine the error rate that would result as a function of a power transmission level of the UE and / or a number of resource blocks in the allocation request and / or a number of high interference resource blocks in the first portion of the shared communication channel and / or a selected modulation and coding scheme level. [15] The base station of claim 14, wherein the allocation error rate calculator is further configured to determine the error rate that would result as a function of at least the number of resource blocks in the allocation request, the number of high-interference resource blocks in the first portion of the shared communication channel, and the selected modulation and coding scheme level.

Images