Abstract:
Embodiments of apparatuses, articles, methods, and systems for power management in wireless networks are generally described herein. Other embodiments may be described and claimed.

Description:
FIELD 
     Embodiments of the present invention relate generally to the field of wireless networks, and more particularly to power management of communication devices used in said wireless networks. 
     BACKGROUND 
     Many wireless communication protocols have power saving modes that allow a network interface card (NIC) of a mobile station to be inactivated when the mobile station is idle and reactivated when the mobile station is engaged in active communications. However, in many instances the costs associated with the latency of communicating activation/deactivation of the NIC to a base station outweighs the benefits provided by powering down the NIC. This is especially true in the case of a wireless communication protocol that strictly choreographs the allocation of uplink and downlink access periods of the various communication devices of the network. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings, in which like references indicate similar elements. 
         FIG. 1  illustrates a network of wireless network nodes which support power management policies as will be described with reference to various embodiments. 
         FIG. 2  illustrates message sequences between a mobile subscriber station and a base station in accordance with various embodiments. 
         FIG. 3  illustrates a media access control frame header that may function as a power management message in accordance with an embodiment. 
         FIG. 4  is a flowchart depicting operation of a mobile subscriber station in accordance with various embodiments. 
         FIG. 5  is a flowchart depicting operation of a base station in accordance with various embodiments. 
         FIG. 6  illustrates a computing device capable of being installed in a host wireless network device in accordance with various embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Various aspects of the illustrative embodiments will be described using terms commonly employed by those skilled in the art to convey the substance of their work to others skilled in the art. However, it will be apparent to those skilled in the art that alternate embodiments may be practiced with only some of the described aspects. For purposes of explanation, specific devices and configurations are set forth in order to provide a thorough understanding of the illustrative embodiments. However, it will be apparent to one skilled in the art that alternate embodiments may be practiced without the specific details. In other instances, well-known features are omitted or simplified in order not to obscure the illustrative embodiments. 
     Further, various operations will be described as multiple discrete operations, in turn, in a manner that is most helpful in understanding the present invention; however, the order of description should not be construed as to imply that these operations are necessarily order dependent. In particular, these operations need not be performed in the order of presentation. 
     The phrase “in one embodiment” is used repeatedly. The phrase generally does not refer to the same embodiment; however, it may. The terms “comprising,” “having,” and “including” are synonymous, unless the context dictates otherwise. 
     In providing some clarifying context to language that may be used in connection with various embodiments, the phrases “A/B” and “A and/or B” mean (A), (B), or (A and B); and the phrase “A, B, and/or C” means (A), (B), (C), (A and B), (A and C), (B and C) or (A, B and C). 
     As used herein, reference to a “component” may refer to a hardware, a software, and/or a firmware component employed to obtain a desired outcome. Although only a given number of discrete components may be illustrated and/or described, such components may nonetheless be represented by additional components or fewer components without departing from the spirit and scope of embodiments of this disclosure. 
       FIG. 1  illustrates a network  100  of wireless network nodes which support power management policies as will be described with reference to various embodiments. In particular, the network  100  may include a mobile subscriber station (MSS)  104  and a base station  108 . The MSS  104  may be in direct wireless communication with the base station  108  via an over-the-air (OTA) link  112 . 
     Communication among the nodes of the network  100  may take place in accordance with one or more of the Institute of Electrical and Electronics Engineers (IEEE) wireless standards, e.g., 802.16-2004/Cor 1-2005 (approved Nov. 8, 2005) as amended by 802.16e-2005 (approved Dec. 7, 2005) along with any revisions, amendments or updates thereto. 
     The MSS  104  may include a wireless network interface, e.g., wireless network interface card (WNIC)  116  to communicatively couple the MSS  104  to other devices of the network  100 , e.g., the base station  108 . The WNIC  116  may facilitate processing of messages to and/or from components of a host  120 . The WNIC  116  may utilize an antenna structure  124  for transmission/reception of radio frequency signals via the OTA link  112 . 
     In various embodiments, the antenna structure  124  may include one or more omnidirectional antennas, which radiate or receive equally well in all directions. 
     In various embodiments, the host  120  may include a driver  128  to drive the WNIC  116  for other components of the host  120  such as a power management component, e.g., power manager  132 . The power manager  132  may control power management operations of the MSS  104  as will be discussed. 
     The base station  108  may include an antenna structure  136 , a WNIC  140 , a host  144  and a driver  148 , similar to like-name components of the MSS  104 . The antenna structure  136 , however, may include one or more directional antennas, which radiate or receive primarily in one direction (e.g., for 120 degrees), cooperatively coupled to one another to provide substantially omnidirectional coverage. In other embodiments, the antenna structure  136  may include one or more omnidirectional antennas, similar to the antenna structure  124 . 
     The host  144  of the base station  108  may include a scheduling component, e.g., scheduler  152 . The scheduler  152  may coordinate transmissions in the network  100  by allocating uplink (UL) access slots to specific subscriber stations of the network  100 . Depending on the nature of the data being communicated, these UL access slots may be allocated on a periodic basis or as a result of a specific bandwidth request by a subscriber station. The scheduler  152  may also allocate contention-based, rather than subscriber-station designated, UL access slots for initial ranging and/or bandwidth requests. The base station  108  may communicate the allocation of the UL access slots to the subscriber stations by transmitting a UL-map in a downlink (DL) subframe. 
     The MSS  104  and the base station  108  may be any type of communication device capable of performing respective operations described herein. In some embodiments these devices may include mobile network client devices such as, but not limited to, a personal computing device, a laptop computing device, a phone, etc., or network infrastructure devices, e.g., a server, an access point, etc. 
       FIG. 2  illustrates message sequences  200  between the MSS  104  and the base station  108  in accordance with various embodiments. The MSS  104  and the base station  108  may engage in a network entry negotiation  204 . This network entry negotiation  204  may include registration and authentication of the MSS  104 , derivation of security measures, discovery of capabilities/settings of the various nodes, etc. 
     In some embodiments, prior to, or contemporaneously with, the network entry negotiation  204  the base station  108  may advertise a power management capability through an information element (IE) sent to the MSS  104 . This may be sent in either a broadcast or a unicast message. 
     During the network entry negotiation  204  the MSS  104  may provide the base station  108  with contexts for one or more power saving classes. A power saving class may describe a sleep schedule (e.g., an alternating sequence of sleep periods and listening periods) that is employed when the power saving class is activated. A context of a particular power saving class may include which connections are associated with the power saving class as well as various attributes of the power saving class. The attributes may include, but are not limited to, activation/deactivation procedures, parameters of the sleep schedule (e.g., intervals between sleep windows, size of sleep windows, etc.), etc. 
     After, or contemporaneously with, network entry negotiation  204  the MSS  104  may establish one or more connections with the base station  108  at  208 . The connections may be services flows characterized by a particular quality of service (QoS) designation based on the type of traffic being communicated. These QoS service flows may include, but are not limited to, best efforts (BE) service, real time variable rate (RT-VR) service, non-real time variable rate (NRT-VR) service, and unsolicited grant service (UGS). 
     The connection establishment  208  may also include updating the contexts of the power saving classes to associate each of the connections with one of the power saving classes. A connection may be associated with a power saving class that provides a desired/compatible sleep schedule. 
     With the appropriate connections established and the contexts of the power saving classes defined as desired, the MSS  104  may perform a fast signaling operation to activate/deactivate a selected power saving class. A fast signaling operation, as used herein, may refer to transmission of a power management message (e.g., a message including power management information) within an uplink access slot not specifically allocated for a power management message. Power management information, as used herein, may include one or more power saving bits, to communicate whether an activation or a deactivation of a particular power saving class is desired, and a connection identifier (ID) that corresponds to a connection which is associated with the power saving class for which activation/deactivation is desired. In some embodiments, the power management information communicated in the power management message may consist solely of the power saving bits and the connection ID. This may facilitate incorporation of the power management information into a variety of different types of messages. 
     The MSS  104  may perform a fast signaling operation to activate a first power saving class, e.g., PSC 1 , by sending power management message  212  including power saving bits and a connection ID. The scheduler  152  of the base station  108  may receive the power management message  212 , determine that it is an activation command through its power saving bits, determine that it pertains to PSC 1  by referencing the stored contexts to find an association between PSC 1  and the connection that corresponds to the connection ID, and activate the PSC 1 . To deactivate PSC 1  at a later time, the MSS  104  may send power management message  216  including appropriate power saving bits and connection ID. The connection ID in the power management message  216  may be the same one that was sent in power management message  212  or another one that is associated with PSC 1 . 
     The MSS  104  may update contexts  220  of one or more of the power saving classes at any time by transmitting management messages, e.g., dynamic service addition messages. 
     In some embodiments, the power saving bits may be piggybacked into a MAC frame header that is being sent for a connection associated with the appropriate power saving class, primarily for another reason (e.g., to request bandwidth for the connection for a data transmission not related to power management). Alternatively, the power management information may be communicated in a MAC frame header that is transmitted solely for communicating the power management information in a contention-based access slot (e.g., a ranging request). Either way, communication of the power management information may be accomplished without the need for a specific request and allocation of a UL access slot for uploading a power management message (along with their associated latencies). 
     Availability of the MSS  104  to receive DL transmissions may be determined by referencing an aggregation of the active power saving classes. For example, the MSS  104  may be available whenever at least one listening window of an active power saving class is present. However, the MSS  104  may be unavailable during periods in which the sleep windows of all of the active power saving classes overlap. During unavailable periods, the MSS  104  may power down the WNIC  116  to conserve power. The scheduler  152  of the base station  108  may either queue any transmissions for the MSS  104  during these periods and send them when the MSS  104  becomes available or simply discard the transmissions. 
       FIG. 3  illustrates a MAC frame header  300  that may function as a power management message in accordance with an embodiment. In particular, the MAC frame header  300  may be a bandwidth request (BR) and UL transmit (TX) power report header. In some embodiments, the MAC frame header  300  may not be followed by a MAC protocol data unit (PDU) payload or cyclic redundancy check (CRC) field. 
     The MAC frame header  300  may include a one-bit header type (HT) field  304 , a one-bit encryption control (EC) field  308 , a three-bit type field  312 , a one-bit power saving bit (PSB) field  316 , a ten-bit BR field  320 , an eight-bit UL TX power field  324 , an eight-bit connection ID (CID) most significant bit (MSB) field  328 , an eight-bit CID least significant bit (LSB) field  332 , and an eight-bit header check sequence (HCS) field  336 . 
     The HT field  304  and EC field  308  may be management fields that convey information pertaining to the type of MAC frame header (e.g., whether it includes a PDU payload and CRC) and encryption. The type field  312  may, in conjunction with the HT field  304  and the EC field  308 , convey additional information as to the specific type of header. For example, in this embodiment, the type field may include a code designating the MAC frame header  300  as a BR and UL TX power report header. 
     The PSB field  316  may include one or more bits that indicate whether an activation or a deactivation of a power saving class is desired. If the PSB field includes one bit, as shown, then having the bit set to one may correspond to an activation request while having it set to zero may correspond to a deactivation request. Other embodiments may include an opposite signaling scenario and/or additional bits. 
     The BR field  320  may be used to request an allocation of bandwidth, in the form of one or more UL access slots, for an upcoming data transmission. The BR may be a number of bytes of UL bandwidth requested by the MSS  104 . 
     The UL TX power field  324  may be the power level, in decibels relative to one milliwatt (dBm), for the burst that carries the MAC frame header  300 . 
     The CID fields, e.g., the CID MSB field  328  and the CID LSB field  332 , may indicate the connection for which the uplink bandwidth is requested. The CID may also be used by the base station  108  to determine to which power saving class the activation/deactivation request pertains by reference to the associations in the stored contexts. 
     The HCS field  336  may be used to detect errors in the MAC frame header  300 . 
     In other embodiments, power management information may be communicated through MAC frame headers other than the BR and UL TX power report header shown. For example, in other embodiments the MAC frame header may be a generic MAC frame header, a BR and carrier to interference and noise ratio (CINR) report header, etc. 
       FIG. 4  is a flowchart depicting operation of the MSS  104  in accordance with various embodiments. At block  404 , the MSS  104  may negotiate, with base station  108 , entry into network  100 . The network entry negotiation may include the power manager  132  providing, to the base station  108 , a context for each of one or more power saving classes. 
     At, or after negotiation of network entry at block  404 , the MSS  104  may establish one or more connections with the base station  108  to accommodate corresponding service flows at block  408 . Along with, or after, the establishment of the one or more connections at block  408 , the contexts of the power saving classes may be updated to reflect an association of the established connections with an appropriate power saving class. 
     In some embodiments, connections of a particular QoS type may have a default association to a particular power saving class. These default associations may then be overridden by updating the contexts of the power saving classes. For example, a connection having BE service may, as a default, be associated with a power saving class I. Consider, e.g., two BE connections being established between the MSS  104  and the base station  108 . If the context of power saving class II is updated to reflect an association with the second BE connection, but not the first, the first BE connection may retain the default association with the power saving class I. 
     With the connections established and the contexts updated as desired at block  412 , the power manager  132  may fast signal activation/deactivation of a power saving class at block  416 . As described above, this may be done by transmitting power management information in a power management message such as a MAC frame header. 
       FIG. 5  is a flowchart  500  depicting operation of the base station  108  in accordance with various embodiments. At block  504 , the scheduler  152  may allocate a number of UL access slots to the subscriber stations of the network  100 , including MSS  104 . This may be communicated through a UL map broadcast in a DL subframe. 
     At block  508 , the scheduler  152  may receive a context for each of the power saving classes of the MSS  104 . These contexts may describe associations between the power saving classes and established connections as well as other parameters of the power saving classes. 
     At block  512 , the scheduler  152  may receive a fast signaling power management message from the MSS  104 . The scheduler may reference the CID of the power management message and compare it to the associations in the stored contexts to determine to which power saving class the power management information pertains. At block  516 , the scheduler  152  may activate/deactivate the appropriate power saving class. The scheduler  152  may schedule UL access slots and/or transmit information to the MSS  104  according to an aggregate of the activated power saving classes of the MSS  104  as described above. 
       FIG. 6  illustrates a computing device  600  capable of being installed in a host wireless network device in accordance with various embodiments. As illustrated, for the embodiments, computing device  600  includes processor  604 , memory  608 , and bus  612 , coupled to each other as shown. Additionally, computing device  600  includes storage  616 , and input/output interfaces  620  coupled to each other, and the earlier described elements as shown. 
     Memory  608  and storage  616  may include in particular, temporal and persistent copies of power management logic  624 , respectively. The power management logic  624  may include instructions that when executed by the processor  604  result in the computing device  600  performing power management operations described in conjunction with various wireless network devices described herein. 
     In various embodiments, the processor  604  may include one or more single-core processors, multiple-core processors, controllers, application-specific integrated circuits (ASICs), etc. 
     In various embodiments, the memory  608  may include RAM, dynamic RAM (DRAM), static RAM (SRAM), synchronous DRAM (SDRAM), dual-data rate RAM (DDRRAM), etc. 
     In various embodiments, storage  616  may include integrated and/or peripheral storage devices, such as, but not limited to, disks and associated drives (e.g., magnetic, optical), universal serial bus (USB) storage devices and associated ports, flash memory, read-only memory (ROM), non-volatile semiconductor devices, etc. 
     In various embodiments, storage  616  may be a storage resource physically part of the wireless network device on which the computing device  600  is installed or it may be accessible by, but not necessarily a part of, the wireless network device. For example, the storage  616  may be accessed over a network. 
     In various embodiments, the input/output interfaces  620  may be configured to be coupled to a network interface, e.g., a WNIC, of a host wireless network device. 
     In various embodiments, computing device  600  may have more or less components, and/or different architectures. In various embodiments, computing device  600  may be installed in an MSS, a base station, or some other wireless network device. 
     Although the present invention has been described in terms of the above-illustrated embodiments, it will be appreciated by those of ordinary skill in the art that a wide variety of alternate and/or equivalent implementations calculated to achieve the same purposes may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. Those with skill in the art will readily appreciate that the present invention may be implemented in a very wide variety of embodiments. This description is intended to be regarded as illustrative instead of restrictive on embodiments of the present invention.