Abstract:
Embodiments of apparatuses, articles, methods, and systems for providing and/or using speculatively allocated bandwidth are generally described herein. Other embodiments may be described and claimed.

Description:
FIELD  
       [0001]     Embodiments of the present invention relate generally to the field of networks, and more particularly to mechanisms for allocating and/or using bandwidth in such networks.  
       BACKGROUND  
       [0002]     Wireless networks may include a number of network nodes in wireless communication with one another over a shared medium of the radio spectrum. One of the network nodes, e.g., a base station (BS), may have a scheduling mechanism to control access to the shared medium for a group of other network nodes, e.g., subscriber stations (SSs). In each frame, the scheduling mechanism may provide a downlink map (DL-MAP) that may alert the SSs to specific regions of a downlink portion of the current frame that are directed to them. A region may be defined by frequencies (e.g., subchannels) and time (e.g., modulation symbols). If data is being transmitted to a particular SS in the downlink portion of the frame, the SS may be alerted, by the DL-MAP, to energize its radio and decoder to receive and decode a region (e.g., subchannels  3 - 6  for symbols  20 - 35 ) that includes that data.  
         [0003]     The scheduling mechanism may also provide an uplink map (UL-MAP) that may alert the SSs to regions of an uplink portion of a frame in which they are allowed to transmit data to the BS. However, unlike the DL-MAP, the UL-MAP is relevant to the following frame, rather than the current frame. That is, the regions that the UL-MAP directs the SSs to are in a frame that follows the frame in which the UL-MAP occupies. This latency may provide the SS with time to format the data it wishes to transmit into the region in which it is allowed to transmit.  
         [0004]     An SS may alert the BS that it wishes to transmit a signal by using a contention-based bandwidth request. Each frame may have a contention region in its uplink portion that may be reserved for these contention-based bandwidth requests. An SS, wishing to transmit a signal to the BS, may upload a randomly selected code in the contention region. The code may simply alert the BS that an SS wishes bandwidth allocation, without conveying any information regarding the particular SS requesting the bandwidth or the amount of bandwidth that is needed to complete transmission. This is done as a code-division multiple access request (CDMA_REQ). The BS may, in a subsequent frame, provide notice to the sender of the CDMA_REQ of an allocation of preliminary bandwidth for an information element (CDMA_BW_ALLOC_IE) in an uplink portion of an upcoming frame. The CDMA_BW_ALLOC_IE may provide sufficient bandwidth for the SS to send a full bandwidth request (BW-REQ), which may convey more details about the SS itself and the resources necessary to complete its contemplated transmission. At that time the BS may allocate sufficient BW for the SS to upload its entire transmission segment in one or more following frames (BW-ALLOC). This contention-based request process is required anytime the SS wishes to transmit data (e.g., internet protocol packets, control traffic, etc.) to the BS.  
         [0005]     The delays due to the UL-MAP relevancy coupled with the delays due to the contention-based bandwidth request may add significant time to a signaling exchange between a BS and an SS. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]     Embodiments of the invention 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 and in which:  
         [0007]      FIG. 1  illustrates a network in accordance with an embodiment of the present invention;  
         [0008]      FIG. 2  illustrates operation of a scheduling mechanism in accordance with an embodiment of the present invention;  
         [0009]      FIG. 3  illustrates frame structures for communications of the network in accordance with an embodiment of the present invention;  
         [0010]      FIG. 4  illustrates frame structures for communications of the network in accordance with another embodiment of the present invention;  
         [0011]      FIG. 5  illustrates operation of the scheduling mechanism in accordance with another embodiment of the present invention;  
         [0012]      FIG. 6  illustrates a subscriber station in accordance with an embodiment of the present invention; and  
         [0013]      FIG. 7  illustrates operation of a subscriber station in accordance with an embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0014]     Illustrative embodiments of the present invention may include network nodes having mechanisms to provide and/or use speculative allocated bandwidth to/from other network nodes.  
         [0015]     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.  
         [0016]     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.  
         [0017]     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.  
         [0018]      FIG. 1  illustrates a network  100  having network nodes  104 ,  108 ,  112 , and  116  communicatively coupled to each other through a wireless network medium  114  in accordance with an embodiment of the present invention. In this embodiment, the network node  104  may control access to one or more frequency channels of the network medium  114  for the network  100  and may also be referred to as a base station  104 . The network nodes  108 ,  112 , and  116  may each communicate with the base station  104  as directed by the base station  104 , and may hereinafter also be referred to as subscriber station  1  (SS 1 )  108 , SS 2   112 , and SS 3   116 .  
         [0019]     The base station  104  may have a scheduling mechanism  120 , which may be a part of the node&#39;s media access control (MAC) layer. The scheduling mechanism  120  may develop a schedule to coordinate data transfers to/from the SSs  108 ,  112 , and  116 . In one embodiment, the scheduling mechanism  120  may include a processing device  122 , which may include, e.g., a processor, a controller, an application-specific integrated circuit, etc., and a storage medium  124 . The storage medium  124  may include instructions, which, when executed by the processing device  122  cause the scheduling mechanism  120  to perform various scheduling, assigning, and/or coordination functions. In one embodiment the processing device  122  and the storage medium  124  may be co-located on the same integrated circuit. In another embodiment, the storage medium  124  may be located on a separate integrated circuit. In various embodiments, the processing device  122  may be a dedicated or a shared resource for the scheduling mechanism  120 .  
         [0020]     In one embodiment, the scheduling mechanism  120  may speculatively allocate bandwidth of the network medium  114  to an SS, e.g., SS 1   108 , for the uploading of data to the base station  104 . This speculative allocation, which may be based at least in part on a status assigned to the SS 1   108 , may be done in anticipation of the upcoming signaling exchange without requiring the reception of a bandwidth request from the SS 1   108 . That is, speculative allocation of bandwidth may be bandwidth allocated based at least partially on conjecture of upcoming need and not necessarily in response to a specific request for bandwidth. Depending on the amount of bandwidth speculatively allocated, the SS 1   108  may avail itself of this bandwidth by either uploading its entire transmission to the base station  104  or by making a request for bandwidth sufficient to upload entire transmission to the base station  104 .  
         [0021]     The scheduling mechanism  120  may communicate said schedule through a wireless network interface  126  and one or more antennas  128  coupled to the base station  104 . The one or more antennas  128  may provide the wireless network interface  126  with communicative access to the network medium  114 .  
         [0022]     In one embodiment the one or more antennas  128  may include a plurality of 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 another embodiment, the one or more antennas  128  may include one or more omnidirectional antennas, which radiate or receive equally well in all directions.  
         [0023]     The network  100  may comply with a number of topologies, standards, and/or protocols. In one embodiment, various interactions of the network  100  may be governed by a standard such as one or more of the ANSI/IEEE 802.16 standards (e.g., IEEE 802.16.2-2004 released Mar. 17, 2004) for metropolitan area networks (MANs), along with any updates, revisions, and/or amendments to such. A network, and components involved therein, adhering to one or more of the ANSI/IEEE 802.16 standards may be colloquially referred to as worldwide interoperability for microwave access (WiMAX) network/components. In various embodiments, the network  100  may additionally or alternatively comply with other communication standards.  
         [0024]      FIG. 2  illustrates operation of the scheduling mechanism  120  in accordance with an embodiment of the present invention. As used herein, numerals within parentheses may refer to operational phases. In this embodiment, the scheduling mechanism  120  may initially assign an SS, e.g., SS 1   108 , a default “normal” status ( 204 ). The scheduling mechanism  120  may monitor events of the network  100  related to SS 1   108  ( 208 ). Events that may be monitored may include but are not limited to, receipt of incoming data from the SS 1   108  and/or transmission of outgoing data to the SS 1   108 . In various embodiments this incoming/outgoing data could be, but is not limited to, internet protocol (IP) packets and control traffic.  
         [0025]     When an event occurs, the scheduling mechanism  120  may make a determination whether or not the event suggests an upcoming signal exchange between the base station  104  and the SS 1   108  ( 212 ). If a monitored event does not suggest an upcoming signaling exchange, the scheduling mechanism  120  may continue to monitor the events ( 208 ). However, if the monitored event does suggest an upcoming signaling exchange, or even an increased probability of an upcoming signaling exchange in accordance with one embodiment, the scheduling mechanism  120  may assign a “signaling” status to the SS 1   108  ( 216 ). In various embodiments, such an event, which may be referred to as an upgrade event, may be data transmitted to/from the SS 1   108  from/to the base station  104  recognized as prompting one or more data transmissions from the SS 1   108  to the base station  104 . While the SS 1   108  is assigned the signaling status, the scheduling mechanism  120  may speculatively allocate bandwidth for the SS 1   108  in one or more frames.  
         [0026]     While the SS 1   108  is assigned the signaling status, the scheduling mechanism  120  may continue to monitor events related to SS 1   108  ( 220 ). When an event occurs, the scheduling mechanism  120  may make a determination whether or not the event suggests an end to a current signaling exchange between the BS  104  and the SS 1   108  ( 224 ). In various embodiments, such an event, which may be referred to as a downgrade event, may be data transmitted to/from the SS 1   108  from/to the base station  104  that is recognized as the last of a transaction, the elapsing of a predetermined amount of time without receiving data transmitted from the SS 1   108 , etc.  
         [0027]     When a downgrade event occurs the scheduling mechanism  120  may assign a normal status to the SS 1   108 . While the SS 1   108  is assigned a normal status, the scheduling mechanism  120  may not speculatively allocate bandwidth. In an embodiment, a normal status assignment may not affect operation of the scheduling mechanism other than with respect to provision/nonprovision of speculatively allocated bandwidth.  
         [0028]      FIG. 3  illustrates frame structures  300  for communications of the network  100  along with a corresponding bar graph  304  depicting an assigned status of SS 1   108 , in accordance with an embodiment of the present invention. In this embodiment, SS 1   108  may be initially assigned a normal status  308  by the scheduling mechanism  120 . During a first frame F 1 , which may have a frame period of, e.g., approximately 5 milliseconds (ms), an upgrade event  312  may occur and be recognized by the scheduling mechanism  120 . Based at least in part on the upgrade event  312 , the scheduling mechanism  120  may assign the SS 1   108  a signaling status  316 .  
         [0029]     In accordance with an embodiment of the present invention, the scheduling mechanism  120  may speculatively allocate bandwidth in one or more of the frames that occur while the SS 1   108  is assigned the signaling status  316 . For example, bandwidth regions  320 ,  324 , and  328  may be speculatively allocated to SS 1   108  in the second through fourth frames F 2 -F 4 , respectively. These regions  320 ,  324 , and  328  may be dedicated to the SS 1   108  whether or not SS 1   108  actually uses or even needs them. SS 1   108  may avail itself of the bandwidth of any/all of the regions  320 ,  324 , and/or  328  for uploading data to the BS  104 . This uploaded data may be, but is not limited to, IP packets and/or control traffic, which may include a further allocation request if the provided bandwidth is insufficient. Allocation of additional bandwidth, due to a further allocation request, may be appended to, or provided independent from, the regions  312 ,  316 , and/or  320 .  
         [0030]     In the fourth frame F 4 , a downgrade event  332  may be recognized by the scheduling mechanism  120  as suggesting an end to a current signaling exchange. Based at least in part on the downgrade event  332 , the scheduling mechanism  120  may reassign the SS 1   108  the normal status  308 . As in F 1 , the scheduling mechanism  120  may not speculatively allocate any bandwidth in F 5  to SS 1   108  due to its normal status. Note that in this embodiment the region  328  may have already been allocated for the fourth frame F 4  when the downgrade event  332  occurs. Therefore, the downgrade event  332  may not affect this particular allocation.  
         [0031]     While the above embodiment depicts the regions  320 ,  324 , and  328  being in each of the frames that occur while the SS 1   108  has a signaling status, other embodiments may adapt the speculative allocation such that the bandwidth is provided only in selected frames that occur while the SS 1   108  has the signaling status. This adaptive speculation may be based on e.g., analysis of past signaling exchanges, to be described in further detail below. Additionally, while the above embodiment depicts the regions  320 ,  324 , and  328  being approximately the same size, other embodiments may provide allocations of different sizes.  
         [0032]      FIG. 4  illustrates frame structures  400  for communications of the network  100  along with a corresponding bar graph  404  depicting an assigned status of SS 1   108  in accordance with another embodiment of the present invention.  
         [0033]     The regions of the frame structures  400  and their interactions with other regions may be briefly described as follows. Frames may be divided by frequencies (e.g., subchannels  0 - 14 ) and by time (e.g., symbols  1 - 50 ). The frames, e.g., the first frame F 1 , may have both a downlink (DL) portion, including, e.g., symbols  1 - 25 , and an uplink (UL) portion, including, e.g., symbols  26 - 50 . It may be noted that, as shown, the DL portion and the UL portion time-share the same channel of the network medium  114  in a process referred to as Time-Division Duplexing (TDD). Other embodiments may use other processes to separate the DL and UL portions such as, but not limited to, Half-Frequency Division Duplexing (HFDD) and Frequency-Division Duplexing (FDD).  
         [0034]     The scheduling mechanism  120  may begin each DL portion with a preamble. The preamble may be a known sequence of transmitted data to be used by the SSs for synchronization and channel estimation. The preamble may be followed by a frame control header (FCH), a DL-MAP, and an UL-MAP. The FCH may include a DL Frame Prefix to specify the burst profile and the length of the DL-MAP.  
         [0035]     The DL-MAP may include, as briefly mentioned above, a schedule of the DL portion of the current frame. For example, in this embodiment, the BS  104  may be transmitting data to SS 1  in the DL portion. Therefore, the scheduling mechanism  120  may use the DL-map to direct the SS 1   108  to energize its radio to a region  408  of the DL portion in which the data is transmitted, e.g., subchannels  7 - 10  for symbols  11 - 25  of the first frame F 1 . The DL-MAP may also direct the SSs to the region of the DL-portion of the first frame F 1  that includes the UL-MAP.  
         [0036]     The data transmitted from the BS  104  to the SS 1   108  may be a signaling request. The scheduling mechanism  120  may recognize this signaling request as an event suggestive of an upcoming signaling exchange with the SS 1   108 , e.g., an upgrade event. For example, it may be expected that the request will be followed by a response, which, in turn, may be followed by an acknowledgment. In anticipation of this upcoming signaling exchange, the scheduling mechanism  120  may update the status of the SS 1   104  from a normal status  412  to a signaling status  416 , as shown in the bar graph  404 .  
         [0037]     While the SS 1   108  is assigned the signaling status  416 , the scheduling mechanism  120  may speculatively allocate bandwidth in anticipation of the SS 1   108  uploading data to the BS  104 , e.g., uploading response to the request. In this embodiment, the scheduling mechanism  120  may speculatively allocate bandwidth as a region  420  in the third frame F 3  and communicate this allocation to the SS 1   108  in the UL-MAP of the second frame F 2 . Note that in this embodiment, due to the UL-MAP relevancy being to the following frame, a speculative allocation of bandwidth in the second frame F 2  may not be made known to the SS 1   108  unless it was communicated in the first frame F 2 . Therefore, in this embodiment, the scheduling mechanism  120  may not speculatively allocate bandwidth in the second frame F 2 .  
         [0038]     In this embodiment, regions  424  and  428  in the fourth frame F 4  and the fifth frame F 5 , respectively, may also be speculatively allocated to SS 1   108 . The dedication of regions  424  and  428  to SS 1   108  may be communicated to SS 1   108  in the third frame F 3  and fourth frame F 4 , respectively.  
         [0039]     In this embodiment, after the SS 1   108  receives and processes the request it may formulate a response to the request. Instead of going through a contention-based request involving, e.g., modulating a code into the contention zone as a CDMA_REQ, receiving CDMA_BW_ALLOC, sending BW_REQ, receiving BW_ALLOC, and sending the full data transmission, the SS 1   108  may simply transmit the response in the regions  420 ,  424 , and/or  428 . This may facilitate a reduction of delays in signaling exchanges. This reduction of delays may be especially noticeable in signaling exchanges having a long series of messages exchanged between the base station  104  and the SS 1   108 . Such signaling exchanges could be of a type such as, but not limited to, network-entry signaling exchanges, hand-off signaling exchanges, and voice-over-internet-protocol signaling exchanges.  
         [0040]     In the present embodiment, the SS 1   108  may require a certain amount of time to process the request, to formulate a response, and to format the response into the allocated bandwidth. This amount of time may involve a number of factors such as the processing capabilities of the SS 1   108 , the nature of the request, the substance of the response, etc. Assuming, for example, it takes the SS 1   108  approximately 20 ms to do these tasks, the first region that the SS 1   108  may able to use may be the region  428  in the fifth frame F 5 . In various embodiments, the scheduling mechanism  120  may record this delay time and account for it in a subsequent signaling exchange involving the same circumstances (e.g., same station, same type of request, etc.). That is, the scheduling mechanism  120  may use this information to provide adaptive speculative allocations in future signaling exchanges. For example, in a subsequent signaling exchange of the same type the scheduling mechanism  120  may begin speculative allocations in the fifth frame F 5 , rather than the third frame F 3 .  
         [0041]     In various embodiments, for one reason or another, an SS may not avail itself of any of the speculatively allocated bandwidth. In these embodiments, the scheduling mechanism  120  may take note of these SSs and refrain from speculatively allocating bandwidth to them in future signaling exchanges.  
         [0042]     In various embodiments, a variety of adaptations similar to those described above may be implemented to facilitate the effective and efficient use of network resources.  
         [0043]      FIG. 5  illustrates operation of the scheduling mechanism  120  in accordance with another embodiment of the present invention. Description of the operational flow of this embodiment may begin with the scheduling mechanism  120  assigning a SS, e.g., SS 1   108 , a normal status ( 504 ). The base station  104 , and more particularly the scheduling mechanism  120 , may recognize an upgrade event, e.g., a signaling event that suggests an upcoming signaling exchange between the base station  104  and the SS 1   108 , and assign the SS 1   108  a signaling status ( 508 ). The scheduling mechanism  120  may determine whether there is a record of the SS 1  being assigned a signaling status before ( 512 ). In one embodiment, this determination may be done by reference to a database.  
         [0044]     If there is not a record of the SS 1   108  previously being assigned a signaling status, the scheduling mechanism  120  may speculatively allocate bandwidth to the SS 1   108  in one or more upcoming frames ( 516 ). The scheduling mechanism  120  may then monitor whether or not the SS 1   108  avails itself of the allocated bandwidth ( 520 ). If it does, the scheduling mechanism  120  may monitor and record utilization attributes ( 524 ). These attributes could include, but are not limited to, how many frames are typically needed for SS 1   108  to formulate and transmit response to certain stimuli, how large typical data packets are in response to certain stimuli, etc. In one embodiment the scheduling mechanism  120  may store the recorded attributes in the database of the base station  104 . If the SS 1   108  does not use the speculatively allocated bandwidth, the scheduling mechanism  120  may record this information ( 528 ) for use at a later time.  
         [0045]     Referring back to operational block  512 , if it is determined that the SS 1   108  has been assigned a signaling status before, the scheduling mechanism  120  may determine if it used speculatively allocated bandwidth in the past ( 532 ). If not, the scheduling mechanism  120  may proceed without providing such allocations ( 536 ), under the assumption that the SS 1   108  is unable to take advantage of them. If the SS 1   108  has used the SAB in the past, the scheduling mechanism  120  may provide SAB ( 540 ). In accordance with one embodiment, this SAB may be adapted based on recorded utilization attributes.  
         [0046]     In various embodiments, the scheduling mechanism  120  may make a determination on whether or not providing SAB to an SS may facilitate quicker signaling exchanges in a number of ways. Additionally, this determination may be made prior to assigning a particular SS a signaling status in the first place. That is, if a particular SS has not used SAB in the past, the scheduling mechanism  120  may not assign a signaling status to that SS in the future.  
         [0047]     The assigned signaling status session of the SS 1   108  may be terminated by the BS  104 , and more particularly the scheduling mechanism  120 , after recognition of a downgrade event that is suggestive of an end of a current signaling exchange between the BS  104  and the SS 1   108 . At the recognition of a downgrade event, the scheduling mechanism  120  may assign the SS 1   104  a normal status ( 544 ).  
         [0048]      FIG. 6  illustrates the SS 1   108  in more detail in accordance with an embodiment of the present invention. In this embodiment, the SS 1   108  may have a transfer mechanism  604  to coordinate data transfers to/from the base station  104 . Similar to the base station  104 , the SS 1   108  may have a wireless network interface  608  coupled to one or more antennas  612  to facilitate communication between the transfer mechanism  604  and the network medium  114 .  
         [0049]     Referring also to  FIG. 7 , if the SS 1   108  wishes to transmit a data transmission to the base station  104  the data transfer mechanism  604 , which may be a part of the SS 1 &#39;s  108  MAC layer, may receive an indication of this and proceed with obtaining sufficient bandwidth for said transmission ( 704 ). In one embodiment, the data transfer mechanism  604  may determine whether there has been any bandwidth speculatively allocated to SS 1   108  ( 708 ). This may be done by referencing the DL-MAP transmitted by the base station  104 . If bandwidth has been speculatively allocated to the SS 1   108 , the data transfer mechanism  604  may recognize this and utilize said bandwidth. In one embodiment the utilization of the bandwidth may be based at least in part on whether it is sufficient to accommodate the full data transmission ( 712 ). If so, the transfer mechanism  604  may cause the full data transmission to be uploaded to the base station  104  in the allocated bandwidth ( 716 ). If the speculatively allocated bandwidth is insufficient to accommodate full data transmission, the transfer mechanism  604  may upload a bandwidth request, e.g., BW_REQ, in the allocated bandwidth ( 720 ). Referring again to block ( 708 ), if there is no speculatively allocated bandwidth, the transfer mechanism  604  may proceed with a contention-based request, e.g., CDMA_BW_ALLOC ( 724 ).  
         [0050]     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.