The present disclosure relates to radio resource allocation in a wireless communications network.
In a wireless communications network, transmitting entities use radio resources to transmit their information to receiving entities. A radio resource is any consumable resource used for the purpose of transmission. Some of the radio resources are local resources and some are network-wide resources which are shared among users of the network or other co-sited networks. Such resources are referred to as shared radio resources. Examples of such resources include channel-time, radio spectrum, power, etc. Appropriate allocation of radio resources affects the performance of the whole network in different aspects, e.g., throughput region, battery lifetime, fairness, etc. Appropriate allocation of radio resources is especially important when considering resource allocation in noisy environments with interfering transmissions from different users who are also sharing the same network media.
Radio resource allocation in radio access technology has been mostly focused on the case of cellular access networks where the goal is to allocate existing spectrum/time resources (e.g., resource blocks in Long Term Evolution (LTE) wireless communications networks) to the users such that some performance attributes are satisfied. Throughput per user is an example of a performance attribute that is managed using radio resource allocation in cellular access networks. An example objective of the radio resource allocation is proportional fairness whereby the base station attempts to schedule the users of a cell such that the throughput per user is proportional to the radio link quality of the user relative to other users of the cell. Note that in cellular access networks, the radio resources of a cell are usually allocated centrally by a single controller. In other words, a central controller (usually the base station) allocates the radio resources for each time frame of transmission of a given cell. While radio resource allocation in cellular access technology is well defined and well-understood, it has not been investigated thus far for random access based radio access technologies including Wireless Local Area Networks (WLANs) and multi-Radio Access Technology (RAT) networks. These networks typically operate in unlicensed spectrum where the radio frequency channel of operation is considered a shared resource. While algorithms exist at the radio level to attempt to enable sharing behaviors such as airtime fairness algorithms, cross radio network level algorithms which tackle the specifics of monitoring, and controlling resource allocation have not been considered, or addressed with current technology. As such, there is a need for systems and methods for radio resource allocation to address the case where the radio resource is shared.
Systems and methods for radio resource allocation across multiple resource dimensions are disclosed. In some embodiments, a method of operation of a network node in a wireless communications network to allocate one or more radio resources to two or more traffic partitions includes obtaining radio resource allocation policies for the two or more traffic partitions; obtaining radio resource usage for the two or more traffic partitions across multiple resource dimensions; and allocating the radio resources to the two or more traffic partitions based on the radio resource usage of the two or more traffic partitions across the multiple resource dimensions and the radio resource allocation policies for the two or more traffic partitions. In this way, the radio resource allocation policies may be enforced across multiple resource dimensions of the wireless communications network.
In some embodiments, the multiple resource dimensions comprise separate users in a Multi-User Multiple-Input Multiple-Output (MU-MIMO) transmission. In some embodiments, the multiple resource dimensions comprise transmissions in a plurality of Radio Frequency (RF) channels. In some embodiments, the multiple resource dimensions comprise transmissions in a plurality of wireless access points.
In some embodiments, obtaining the radio resource usage for the two or more traffic partitions in the plurality of wireless access points comprises operating one or more access points in promiscuous mode to measure the radio resource usage of other access points that are not in promiscuous mode and the users of those other access points, and having the access points that are operating in promiscuous mode supply the measured radio resource usage to the network node.
In some embodiments, obtaining the radio resource usage for the plurality of traffic partitions in the plurality of wireless access points comprises each of the plurality of access points measuring the radio resource usage for the two or more traffic partitions by measuring its own transmissions and the transmissions from its users, and having the access point supply the measured radio resource usage to the network node.
In some embodiments, at least one of the plurality of wireless access points operates in another wireless communications network that is different than the wireless communications network of the network node. In some embodiments, the other wireless communications network uses a different Radio Access Technology (RAT) that is different than a RAT used by the wireless communications network of the network node. In some embodiments, the wireless communications network of the network node is a Wireless Local Area Network (WLAN) and the other wireless communications network is a Long Term Evolution (LTE) network such as a LAA-LTE or Licensed Assisted Access Long Term Evolution.
In some embodiments, the network node is an aggregate point comprising a central scheduler and a resource allocation unit. In some embodiments, the network node is a wireless access point comprising a scheduler that is separate from the Medium Access Control (MAC) and Physical (PHY) layers of the wireless access point. In some embodiments, the scheduler is integrated with the MAC and PHY layers of the wireless access point.
In some embodiments, a method of operation of a network node in a wireless communications network to allocate one or more radio resources to two or more traffic partitions includes obtaining radio resource allocation policies for the two or more traffic partitions; obtaining radio resource usage for the two or more traffic partitions across multiple resource dimensions comprising both uplink and downlink transmissions; and allocating the radio resources to the two or more traffic partitions based on the radio resource usage of the two or more traffic partitions across the multiple resource dimensions and the radio resource allocation policies for the two or more traffic partitions.
In some embodiments, a method of operation of a network node in a wireless communications network to allocate one or more radio resources to two or more traffic partitions includes obtaining radio resource allocation policies for the two or more traffic partitions; obtaining radio resource usage for the two or more traffic partitions across multiple resource dimensions comprising transmissions in a plurality of wireless access points operating on the same RF channel; and allocating the radio resources to the two or more traffic partitions based on the radio resource usage of the two or more traffic partitions across the multiple resource dimensions and the radio resource allocation policies for the two or more traffic partitions.
In some embodiments, a method of operation of a network node in a wireless communications network to allocate one or more radio resources to two or more traffic partitions includes obtaining radio resource allocation policies for the two or more traffic partitions comprising a percentage of the one or more radio resources allocated to each traffic partition of the two or more traffic partitions and obtaining the percentage of radio resource usage for the two or more traffic partitions across multiple resource dimensions for the two or more traffic partitions. The method also includes, for each transmission across the multiple resource dimensions, deducting an amount of the radio resource used by each of the two or more traffic partitions from the corresponding radio resource credits. The method also includes selecting the traffic partition with the largest corresponding radio resource credit for the next transmission and, if the traffic partition with the largest corresponding radio resource credit does not have any pending transmissions, setting that radio resource credit to zero. If each of the radio resource credits is at or below zero, the method includes setting each radio resource credit equal to a predetermined base credit multiplied by the percentage of the radio resource allocated to the corresponding traffic partition.
In some embodiments, a network node for use in a wireless communications network is adapted to obtain radio resource allocation policies for two or more traffic partitions; obtain radio resource usage for the two or more traffic partitions across multiple resource dimensions; and allocate radio resources to the two or more traffic partitions based on the radio resource usage of the two or more traffic partitions across the multiple resource dimensions and the radio resource allocation policies for the two or more traffic partitions.
In some embodiments, a network node for use in a wireless communications network includes at least one processor and a memory coupled to the at least one processor. The memory contains instructions executable by the at least one processor whereby the network node is operative to obtain radio resource allocation policies for two or more traffic partitions; obtain radio resource usage for the two or more traffic partitions across multiple resource dimensions; and allocate radio resources to the two or more traffic partitions based on the radio resource usage of the two or more traffic partitions across the multiple resource dimensions and the radio resource allocation policies for the two or more traffic partitions.
In some embodiments, a network node for use in a wireless communications network includes a policy obtaining module operative to obtain radio resource allocation policies for two or more traffic partitions; a usage obtaining module operative to obtain radio resource usage for the two or more traffic partitions across multiple resource dimensions; and an allocation module operative to allocate radio resources to the two or more traffic partitions based on the radio resource usage of the two or more traffic partitions across the multiple resource dimensions and the radio resource allocation policies for the two or more traffic partitions.
Those skilled in the art will appreciate the scope of the present disclosure and realize additional aspects thereof after reading the following detailed description of the embodiments in association with the accompanying drawing figures.
The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serve to explain the principles of the disclosure.
The embodiments set forth below represent information to enable those skilled in the art to practice the embodiments and illustrate the best mode of practicing the embodiments. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure and the accompanying claims.
While the present disclosure is applicable to many types of wireless communications networks, most of the examples focus on Wireless Local Area Networks (WLANs). A WLAN is a wireless access technology which is considered very prone to interference and noise. In WLANs operating on the same frequency channel, the medium (channel-time) is shared among all the transmitting entities. Thus there needs to be a Medium Access Control (MAC) to manage the access of the Access Points (APs) referred to herein as wireless access points; and Stations (STAs) (referred to herein as wireless devices) to the medium. WLANs are using Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard series to control the medium access. A Basic Service Set (BSS) is considered to be the basic building block of a WLAN as defined in the IEEE 802.11 standards. In an infrastructure mode WLAN, a BSS consists of an AP with a unique MAC address and the clients (non-AP stations in WLAN) associated and connected to it. A BSS is uniquely identified by a Basic Service Set Identifier (BSSID) which is the MAC address of the AP in the BSS. An Extended Service Set (ESS), however, is a set of interconnected BSSs. In an ESS, BSSs are connected through the distribution system. A distribution system (DS) connects access points in an extended service set. A WLAN deployment consists of one or more ESSs.
The fast emergence of new wireless access technologies with various supported rates and features makes it difficult to ensure that a system is compatible with desired system requirements. Bandwidth policing is part of the system functionalities required to provide desired levels of service in wireless access technologies over different traffic partitions.
Bandwidth policing is mostly defined as incoming traffic rate control into the APs/base stations from the core network towards the radio medium. However, bandwidth policing can be considered to cover more dimensions of wireless communication, i.e., policing the channel-time, controlling the radio spectrum, scheduling of the incoming packets, control of Multi-User-Multiple Input Multiple Output (MU-MIMO) transmissions, etc.
Bandwidth policing can be used for both Uplink (UL) and Downlink (DL) traffic. There may be different strategies for policing the UL and DL traffic, or there may be a unified strategy for both UL and DL.
Bandwidth policing can be placed at the radio level (e.g., at AP in WLANs or a base station in cellular networks) or at an aggregate point level (e.g., a Wireless Access Controller in WLANs). By placing it at the radio level, this creates the opportunity to use the immediate information at the radio level in the bandwidth policing decisions. By performing the bandwidth policing at the aggregate point level, traffic may be throttled or shaped at the aggregate point (ingress and egress points) to avoid congesting the APs/base stations.
Bandwidth policing can be placed at the STA level or at the STA group level (e.g., SSID level in WLANs). In the STA level bandwidth policing, the traffic (UL and DL) of each individual STA can be policed according to some predefined service profiles. Traffic policing can also be placed at the STA group level where a group of STAs are treated according to the same service profile.
Allocating radio resources based on the usage across multiple resource dimensions allows for a greater control of the actual usage of the radio resources and a greater ability to enforce the radio resource allocation policies, according to some embodiments. In this regard, various dimensions of the transmission media may be controlled/involved in the resource control procedure. The different dimensions considered may include channel-time, radio frequency spectrum, spatial usage of the media, capability of concurrent spatial transmissions (MU-MIMO), multi-channel transmissions, cross-RAT transmissions (unlicensed Long Term Evolution (LTE), Wi-Fi, etc.), and combined uplink and downlink resources. One possible goal would be to control the level of service (which can be defined by a network administrator for example) to different traffic partitions defined in the network by controlling the access of different users to the radio resources (channel-time and frequency spectrum) in a network capable of MU-MIMO technology and multi-RAT transmissions and all over the volume usage of the network. In some embodiments, the radio resource allocation policies may be defined per traffic partition over the geographical area of a multi-RAT network.
As one method of implementing the radio resource allocation of step 104,
Each time a frame is transmitted (either successfully or failed after reaching the maximum retransmission limit) and the credit deducted from the credit buckets, the traffic partition credits are checked to determine if all of them are equal to or less than zero (step 204). If so, the wireless access point 12 allocates credits according to the percentage limits included in the radio resource allocation policies (step 206). For example, there may be a fixed Base Time Credit (BTC), e.g., 100 ms and the credits will be allocated according to the BTC as well as the percentage limit of each traffic partition:
Partition_Crediti=Pi×BTC
where Pi is the percentage limit of traffic partition i. For example, the radio resource allocation policies shown in
Returning to
In order to account for the radio resource usage across the multiple resource dimensions, the credit buckets need to be updated for radio resource usage in each of the multiple resource dimensions. One way to acquire these usage statistics is shown in
The aggregate point 18 may operate as in the methods described in
The process discussed in
The method can be extended for clustered APs (such as wireless access points 12-1 and 12-2) which are working on the same WLAN channel and serving the same set of traffic partitions (the same configured traffic partitions). The following possible embodiments can be used to control the channel time allocations in a cluster of APs. As shown in
Alternatively, or in addition to using the aggregate point 18, if the wireless access points 12 form a dense cluster, another option may become available. It is well known in the industry that Wi-Fi radios may be operated in a “promiscuous” mode—that is, a mode in which the devices are capable of receiving all Wi-Fi packets transmitted on a channel regardless if they are intended for the Wi-Fi radio. Promiscuous mode is often used by Wi-Fi radio applications such as “Omnipeek” as an OTA—“over the air” packet sniffer—similar to the “Wireshark” application which is used to monitor Ethernet traffic over a wired connection. By setting a wireless access point 12 to operate in promiscuous mode, that wireless access point 12 is aware of the transmissions initiated by the other wireless access points 12 in the cluster. When that wireless access point 12 detects a packet transmission from other wireless access points 12, it deducts the channel time usage of the transmission from the credit bucket of the traffic partition it is associated with. In some embodiments, more than one or even all of the wireless access points 12 will be operating in promiscuous mode. Moreover, as radio access technologies evolve, the ability of the wireless access point to monitor not only 802.11 Wi-Fi packets, but also alternate wireless protocols such as BlueTooth, ZigBee, IPv6 over Low power Wireless Personal Area Networks (6LoWPAN), License Assisted Access LTE (LAA-LTE), LTE-Unlicensed (LTE-U), Digital Enhanced Cordless Telecommunication (DECT), and others as they may operate in the same shared spectrum; therefore consuming radio resources while transmitting and receiving data.
When a queue becomes empty in a wireless access point 12, it broadcasts its status to the other wireless access points 12. If a queue becomes empty in all the wireless access points 12 in the cluster, they all reset the credit bucket for that traffic partition. This broadcasting process could be performed over the distribution system (backhaul link) to the wireless access points 12 in the cluster to avoid wasting available air time.
By performing the solutions in disclosed in
An idea similar to the one used for clustered wireless access points 12 can also be used for multi-channel transmissions. Separate credit buckets are kept for each non-overlapping channel. When any channel is used (either as the primary or the secondary), the credit is deducted and a credit deduction report is sent to the aggregate point 18 or accounted for by a wireless access point 12 operating in promiscuous mode. A function (e.g., a sum) of the credit deductions on all the channels can be used for managing the credit increase phase and packet scheduling.
MU-MIMO is considered a new advanced MIMO technology in the new generation of wireless access technology. In WLAN networks, a wireless access point 12 broadcasts each of its transmissions over the air interface, making WLAN channel blocked for other transmissions. Therefore, at each time, only one frame can be transmitted on the air. In MU-MIMO, by using explicit channel feedback and beam-forming, a wireless access point 12 can transmit multiple frames to different WLAN wireless devices 14. This is done by using an appropriate pre-coding matrix at the transmitter. Since in MU-MIMO multiple frame transmissions are possible, the channel time usages of different traffic partitions may overlap. To apply the channel-time control scheme in wireless access points 12 equipped with MU-MIMO, different approaches may be considered.
First, the total channel time usages of all the traffic partitions should follow the percentage limits. In this case, when a MU-MIMO transmission is done, the total channel time spent is deducted from the credit buckets of all the traffic partitions involved in the MU-MIMO transmission. For example, if the MU-MIMO transmission consists of two frames associated to two different traffic partitions, the channel time usage will be deducted from both credit buckets. Since in this approach the accumulated time usages are more than the BTC value, credit increase epochs may be visited quite regularly. Moreover, this approach may not work fairly since MU-MIMO is an opportunity for wireless devices 14 located in good positions to use the channel concurrently and improve the whole system throughput. Decreasing the credits of all the involved traffic partitions by the total channel time usage may be considered unfair.
An alternative approach is the following: When a MU-MIMO transmission is done, the total channel time usage will be split according to some rules. An example could be to split it equally among the involved traffic partitions. Another approach is to split it according to the percentage limits of the involved traffic partitions, i.e.,
In other words, it is assumed that at the times at which the channel was occupied by more than one traffic partition, the channel time usage of each traffic partition is equal to a fraction of the total channel time usage in MU-MIMO transmissions.
As discussed above, the location of the scheduler and the traffic partition queues can be inside the MAC layer or they may be located on top of the upper MAC layer. The location where the methods are implemented may affect the speed of convergence of the algorithm. As the distance of the algorithm from the PHY layer increases, the speed of convergence of the algorithm decreases and more ripples (variations) will be observed in channel time allocation over different traffic partitions.
In one embodiment, a computer program including instructions which, when executed by at least one processor, causes the at least one processor to carry out the functionality of the network node 38 according to any one of the embodiments described herein is provided. In one embodiment, a carrier containing the aforementioned computer program product is provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium (e.g., a non-transitory computer readable medium such as the memory 46).
The following acronyms are used throughout this disclosure.
Those skilled in the art will recognize improvements and modifications to the embodiments of the present disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein and the claims that follow.
Filing Document | Filing Date | Country | Kind |
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PCT/IB2015/053943 | 5/27/2015 | WO | 00 |