BACKGROUND

In wireless mobile broadband communication systems, uplink feedback channel may be used to assist closed loop operation. For example, in systems compliant with an Institute of Electrical and Electronics Engineers (IEEE) 802.16m standard, two kinds of feedback channels are defined to assist closed loop multiple-input and multiple-output (MIMO) operations. One type of channel is referred to as a primary fast feedback channel, and the other type of channel is referred to as a secondary fast feedback channel. The primary fast feedback channel utilizes sequence modulation to convey 4-6 bits in a 6x6 uplink control distributed resource unit (DRU). The secondary fast feedback channel utilizes coherent detection to convey 7-24 bits in a 6x6 DRU. The primary fast feedback channel is more robust than the secondary fast feedback channel, but on the other hand the secondary fast feedback channel has higher throughput than the primary fast feedback channel. A feedback advanced map (A-MAP) allocation information element (IE) is utilized to allocate and deallocate a feedback channel for a specific mobile station (MS). In the case wherein a periodical allocation is implemented, the base station (BS) specifies a transmission period and a transmit duration. With limited signaling bit length, the transmit duration is normally represented exponentially such as 4 ^P periods. If 3 bits are used to represent^?, then the transmit duration may be from 1 period to 16384 frames.

Deallocation may be involved if the base station sees there is no need for the mobile station to transmit feedback according to previous allocation. An example scenario is when a user canceled downloading a large sized file. If the allocation is very long, and there is a 1% chance the mobile stations might miss the deallocation A-MAP IE, there is a chance that the mobile station will continue transmitting on the deallocated feedback channels without this being known by the base station. In such a situation, unnecessary interference may be generated and causing collisions in the deallocated feedback channel. From the perspective of the base station, the lost deallocation A-MAP IE may be detected with collision detection on the deallocated feedback channel. However, this relies on a smart base station implementation, and the detection reliability needs to be guaranteed for multiple periods. In a worst case scenario, the base station may not perform collision detection, and the mobile station will continue sending on a deallocated feedback channel until the expiration of the allocation period.

DESCRIPTION OF THE DRAWING FIGURES Claimed subject matter is particularly pointed out and distinctly claimed in the concluding portion of the specification. However, such subject matter may be understood by reference to the following detailed description when read with the accompanying drawings in which:

FIG. 1 is a block diagram of a channel feedback system capable of implementing feedback channel release for a wireless network in accordance with one or more embodiments;

FIG. 2 is a block diagram of a wireless wide area network utilizing a channel feedback system in accordance with one or more embodiments;

FIG. 3 is a block diagram of a feedback deallocation release confirmation procedure in accordance with one or more embodiments;

FIG. 4 is a flow diagram of a method for implementing feedback channel release in accordance with one or more embodiments; and

FIG. 5 is a block diagram of an information handling system capable of implementing feedback channel release in accordance with one or more embodiments.

It will be appreciated that for simplicity and/or clarity of illustration, elements illustrated in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, if considered appropriate, reference numerals have been repeated among the figures to indicate corresponding and/or analogous elements.

DETAILED DESCRIPTION In the following detailed description, numerous specific details are set forth to provide a thorough understanding of claimed subject matter. However, it will be understood by those skilled in the art that claimed subject matter may be practiced without these specific details. In other instances, well-known methods, procedures, components and/or circuits have not been described in detail.

In the following description and/or claims, the terms coupled and/or connected, along with their derivatives, may be used. In particular embodiments, connected may be used to indicate that two or more elements are in direct physical and/or electrical contact with each other. Coupled may mean that two or more elements are in direct physical and/or electrical contact. However, coupled may also mean that two or more elements may not be in direct contact with each other, but yet may still cooperate and/or interact with each other. For example, "coupled" may mean that two or more elements do not contact each other but are indirectly joined together via another element or intermediate elements. Finally, the terms "on," "overlying," and "over" may be used in the following description and claims. "On," "overlying," and "over" may be used to indicate that two or more elements are in direct physical contact with each other. However, "over" may also mean that two or more elements are not in direct contact with each other. For example, "over" may mean that one element is above another element but not contact each other and may have another element or elements in between the two elements. Furthermore, the term "and/or" may mean "and", it may mean "or", it may mean "exclusive-or", it may mean "one", it may mean "some, but not all", it may mean "neither", and/or it may mean "both", although the scope of claimed subject matter is not limited in this respect. In the following description and/or claims, the terms "comprise" and "include," along with their derivatives, may be used and are intended as synonyms for each other.

Referring now to FIG. 1, a block diagram of a channel feedback system for a wireless network capable of implementing feedback channel release in accordance with one or more embodiments will be discussed. As shown in FIG. 1, a channel feedback system 100 may comprise a base station 110 having one or more antennas 112 communicating with a mobile station 114 having one or more antennas 116. In one or more embodiments, base station 110 may transmit data packets via a downlink (DL) channel 118 to mobile station 114. Feedback may be provided from mobile station 114 to base station 110 in a feedback arrangement comprising a two-level adaptive feedback framework comprising a primary uplink (UL) fast feedback channel 120 and a secondary uplink fast feedback channel 122. Primary UL feedback channel 120 may provide wideband channel quality indicator (CQI) reports with robust data rate from mobile station 114 to transmitter regarding downlink channel 118. Secondary UL feedback channel 122 may provide sub-band CQI reports from mobile station 114 to base station 110 using an adaptive transmission rate. Secondary UL fast feedback channel 122 may utilize link adaptation with event-driven transmission in order to enhance the transmission efficiency with a reduced overhead. Such a two-channel feedback system 100 as shown in FIG. 1 provides flexibility for an independent fast feedback channel design in order to optimize the performance of each channel. For example, the two-channel feedback system may achieve an optimal or a nearly optimal performance under different permutation modes, although the scope of the claimed subject matter is not limited in this respect.

In one or more embodiments, primary UL feedback channel 120 may be referred to as a primary CQI channel (PCQICH) and secondary feedback channel 122 may be referred to as a secondary CQI channel (SCQICH). Optimized Bose and Ray-Chaudhuri (BCH) codes may be utilized used for both primary (PCQICH) fast feedback channel 120 and/or secondary (SCQICH) fast feedback channel 122 having a relatively simplified design and reduced complexity in order to fit the feedback information into different tile sizes. In one or more embodiments, primary fast feedback channel 120 may utilize semi-orthogonal sequences, for example of length 12, to support up to 6 information bits with optimized performance, and furthermore may utilize larger diversity order. Mobile station 114 may utilize a non-coherent design to support fast feedback channel transmission with noncoherent detection in high speeds such as when speed is larger than 120 kilometers per hour (kmph), although the scope of the claimed subject matter is not limited in this respect.

In one or more embodiments, primary CQI channel 120 may support lower rate, less frequent, periodic CQI feedback transmission from mobile station 114 to base station

110. Primary CQI channel 120 may transmit average CQI and/or multiple-input, multiple- output (MIMO) feedback information and to provide reliable basic connections from mobile station 114 to base station 110. Primary CQI channel 120 may be available to all users who need to feedback CQI in the uplink. For example, the base station 110 may allocate resources for primary fast feedback channel 120 and specify the feedback frequency based on the channel variation characteristics for each individual user, referred to as a subscriber station or mobile station 114, embodied as mobile station 114. The resource allocation information may be sent to the mobile station 114 to regulate its CQI feedback behavior.

In one or more embodiments, the secondary fast feedback channel 122 may support more advanced features than the primary fast feedback channel 120, for example multiple-input, multiple-output (MIMO), fractional frequency reuse (FFR), frequency selective scheduling (FSS), and so on, with greater efficiency and is used when there is data to be transmitted. Furthermore, secondary fast feedback channel 122 may provide CQI feedback more frequently and/or with finer granularity than primary fast feedback channel 120. That is, secondary fast feedback channel 122 may support a higher payload feedback of narrow band CQI and MIMO feedback information, which may include MIMO effective signal-to-interference and noise ratio (SINR) per codeword, transmission rank, and pre-coding matrix index (PMI), and so on, on demand, and the transmission may be event driven. To ensure robust transmission while maximizing throughput of secondary fast feedback channel 122, link adaptation may be utilized on secondary fast feedback channel 122, and which may be utilized based at least in part on user location and/or channel condition to increase feedback efficiency. In such an arrangement, center users may take advantage of their relatively higher SINR and transmit CQIs at higher rates with an increased efficiency. As a result, secondary fast feedback channel 122 may cover users with localized resource allocation via downlink channel 118 that involves feeding back more CQI to support features such as FSS, MIMO, and so on, while users with very poor channel quality may not achieve meaningful gain feeding back more CQI using secondary fast feedback channel 122. Per a request from a subscriber station, the base station 110 may decide whether to allocate secondary fast feedback channel 122, when to allocate secondary fast feedback channel 122, the amount of resources involved and the corresponding index, transmission frequency, rate, and so on, and relay such information to the mobile station 114. Further details of channel feedback system 100 are discussed, below. An example network implementing channel feedback system 100 is shown in and described with respect to FIG. 2, below. Referring now to FIG. 2, a block diagram of a wireless wide area network utilizing a channel feedback system implementing feedback channel release in accordance with one or more embodiments will be discussed. As shown in FIG. 2, network 200 may be an internet protocol (IP) type network comprising an internet 210 type network or the like that is capable of supporting mobile wireless access and/or fixed wireless access to internet 210. In one or more embodiments, network 200 may be in compliance with a Worldwide Interoperability for Microwave Access (WiMAX) standard or future generations of WiMAX, and in one particular embodiment may be in compliance with an Institute for Electrical and Electronics Engineers 802.16m standard (IEEE 802.16m). In one or more alternative embodiments network 200 may be in compliance with a Third Generation Partnership Project Long Term Evolution (3GPP LTE) or a 3GPP2 Air Interface Evolution (3GPP2 AIE) standard. In general, network 200 may comprise any type of orthogonal frequency division multiple access (OFDMA) based wireless network, and the scope of the claimed subject matter is not limited in these respects. As an example of mobile wireless access, access service network (ASN) 212 is capable of coupling with base station (BS) 214 to provide wireless communication between subscriber station (SS) 216 and internet 210. Subscriber station 216 may comprise a mobile type device or information handling system capable of wirelessly communicating via network 200, for example a notebook type computer, a cellular telephone, a personal digital assistant, or the like. ASN 212 may implement profiles that are capable of defining the mapping of network functions to one or more physical entities on network 200. Base station 214 may comprise radio equipment to provide radio-frequency (RF) communication with subscriber station 216, and may comprise, for example, the physical layer (PHY) and media access control (MAC) layer equipment in compliance with an IEEE 802.16m type standard. Base station 214 may further comprise an IP backplane to couple to internet 210 via ASN 212, although the scope of the claimed subject matter is not limited in these respects.

Network 200 may further comprise a visited connectivity service network (CSN) 224 capable of providing one or more network functions including but not limited to proxy and/or relay type functions, for example authentication, authorization and accounting (AAA) functions, dynamic host configuration protocol (DHCP) functions, or domain name service controls or the like, domain gateways such as public switched telephone network (PSTN) gateways or voice over internet protocol (VOIP) gateways, and/or internet protocol (IP) type server functions, or the like. However, these are merely example of the types of functions that are capable of being provided by visited CSN or home CSN 226, and the scope of the claimed subject matter is not limited in these respects. Visited CSN 224 may be referred to as a visited CSN in the case for example where visited CSN 224 is not part of the regular service provider of subscriber station 216, for example where subscriber station 216 is roaming away from its home CSN such as home CSN 226, or for example where network 200 is part of the regular service provider of subscriber station but where network 200 may be in another location or state that is not the main or home location of subscriber station 216. In a fixed wireless arrangement, WiMAX type customer premises equipment (CPE) 222 may be located in a home or business to provide home or business customer broadband access to internet 210 via base station 220, ASN 218, and home CSN 226 in a manner similar to access by subscriber station 216 via base station 214, ASN 212, and visited CSN 224, a difference being that WiMAX CPE 222 is generally disposed in a stationary location, although it may be moved to different locations as needed, whereas subscriber station may be utilized at one or more locations if subscriber station 216 is within range of base station 214 for example. In accordance with one or more embodiments, operation support system (OSS) 228 may be part of network 200 to provide management functions for network 200 and to provide interfaces between functional entities of network 200. Network 200 of FIG. 2 is merely one type of wireless network showing a certain number of the components of network 200, however the scope of the claimed subject matter is not limited in these respects.

Referring now to FIG. 3, a block diagram of a feedback deallocation release confirmation procedure in accordance with one or more embodiments will be discussed. The arrangement shown in FIG. 3 illustrates a general description of a feedback deallocation confirmation procedure in accordance with one or more embodiments. In one or more embodiments, base station 110 transmits a feedback deallocation advanced map (A-MAP) information element (IE) 310 to mobile station 114, for example via downlink channel 118 as shown in FIG. 1. The deallocation A-MAP IE transmitted by base station 110 to mobile station 114 directs mobile station 114 to deallocate utilization of the feedback channels, for example primary uplink feedback channel 120 and/or secondary uplink feedback channel 122 as shown in FIG. 1. In response to receiving feedback deallocation A-MAP IE 310 from base station 110, mobile station 114 confirms the receipt of the feedback deallocation A-MAP IE 310 by transmitting a deallocation confirmation 312 to base station 110 so that base station 110 knows whether the feedback channel has been properly deallocated. Thus, in one or more embodiments, after sending a feedback deallocation A-MAP IE 310 to mobile station 114, base station 110 will expect to receive a deallocation conformation 312 from mobile station. In the event a deallocation confirmation 312 is received, the base station may then reallocate the feedback channel to another mobile station. However, in the event case no deallocation confirmation 312 is received by the base station 110, the base station optionally may resend one or more feedback deallocation A-MAP IEs 310 until a deallocation confirmation 312 is received, or until a time out is reached.

In one or more embodiments, the deallocation confirmation 312 sent from mobile station 114 to base station 110 may be defined utilizing one code word in the primary fast feedback channel 120. However, other special formats for deallocation confirmation 312 may be utilized, and the scope of the claimed subject matter is not limited in this respect. In one or more embodiments, deallocation confirmation 312 may be send as one code word in primary fast feedback channel 120 because primary fast feedback channel 120 is more robust than secondary fast feedback channel 122, and in one or more embodiments the deallocation confirmation 312 may be even more robust than a normal primary fast feedback channel transmission because the detection of the deallocation confirmation 312 may simply involve judging if the special deallocation confirmation 312 code word is sent or if some other signal is sent.

An example system for feedback channel deallocation is shown in Table 1, below.

Table 1 - Feedback Allocation A-MAP IE

As shown in Table 1, the feedback allocation A-MAP IE arrangement includes an acknowledgement (ACK) allocation flag for example as provided in a hybrid automatic repeat request (HARQ) type system. If the ACK allocation flag is equal to 1, then a 6 bit HARQ feedback allocation (HFA) indicates the HARQ index. Mobile station 114 utilizes the indicated HARQ feedback channel to transmit the successful reception of the feedback deallocation A-MAP IE 312 to base station 110. An example method for implementing feedback channel release is shown in and described with respect to FIG. 4, below.

Referring now to FIG. 4, a flow diagram of a method for implementing feedback channel release in accordance with one or more embodiments will be discussed. Although

FIG. 4 shows one example order of method 400, various other orders may likewise be implemented, including more or fewer blocks than shown in FIG. 4, and the scope of the claimed subject matter is not limited in these respects. As shown in FIG. 4, a communication link may be established between the base station 110 and a mobile station 114 at block 410. The base station 110 transmits a feedback allocation A-MAP IE 310 to the mobile station 114 at block 412 to allocate a feedback channel to be utilized by the mobile station 114 for various communication, for example to transmit a channel quality indicator (CQI), for various hybrid automatic repeat request (HARQ) messages, and/or for a other feedback transmissions to support multiple-input and multiple-output (MIMO) communication. In one or more embodiments, the mobile station 114 send feedback to base station 110 at block 414 in primary fast feedback channel 120 and/or secondary fast feedback channel 122 according to the feedback allocation A-MAP IE 310 transmitted to the mobile station 114. In one or more embodiments, the feedback allocation includes an allocation period during which mobile station 114 may utilize the allocated feedback channel, such as a short-term feedback period (p) or a long-term feedback period (q). A determination may be made at block 416 whether the feedback allocation should be terminated, for example prior to the end of the allocated feedback period. If no determination is made to terminate the allocation, the mobile station 114 may continue to send feedback to the base station 110 based on the feedback allocation. However, in the event a determination is made that the feedback allocation should be terminated, the base station 110 transmits a feedback deallocation A-MAP IE 310 at block 418 to mobile station 114. In response to receiving the feedback deallocation A-MAP IE 310, the mobile station 114 transmits a deallocation confirmation 312 at block 420 to base station 110. A determination may be made at block 422 if the deallocation confirmation 312 is received by base station 110. If the base station 110 did not receive the deallocation confirmation 312 from the mobile station 114, the base station 110 optionally may retransmit the feedback deallocation A-MAP IE 310 at block 418 one or more additional times, and/or mobile station 114 optionally may retransmit the deallocation confirmation 312 to base station 110 one or more additional times. In the event that base station 110 receives the deallocation confirmation 422, or at the end of a predetermined timeout period or a after predetermined number of retransmissions, the base station 110 may reallocate the feedback channel resources to another mobile station at block 424. Method 400 may then operate for feedback channel allocation and/or deallocation for the other mobile station. Referring now to FIG. 5, a block diagram of an information handling system capable of implementing feedback channel release in accordance with one or more embodiments. Information handling system 500 of FIG. 5 may tangibly embody one or more of any of the elements of channel feedback system 100 as shown in and described with respect to FIG. 1, and/or any network element of network 200 of FIG. 2. For example, information handling system 500 may represent the hardware of base station 110 and/or mobile station 114, with greater or fewer components depending on the hardware specifications of the particular device or network element. Although information handling system 500 represents one example of several types of computing platforms, information handling system 500 may include more or fewer elements and/or different arrangements of elements than shown in FIG. 5, and the scope of the claimed subject matter is not limited in these respects.

Information handling system 500 may comprise one or more processors such as processor 510 and/or processor 512, which may comprise one or more processing cores.

One or more of processor 510 and/or processor 512 may couple to one or more memories

516 and/or 518 via memory bridge 514, which may be disposed external to processors 510 and/or 512, or alternatively at least partially disposed within one or more of processors

510 and/or 512. Memory 516 and/or memory 518 may comprise various types of semiconductor based memory, for example volatile type memory and/or non-volatile type memory. Memory bridge 514 may couple to a graphics system 520 to drive a display device (not shown) coupled to information handling system 500.

Information handling system 500 may further comprise input/output (I/O) bridge 522 to couple to various types of I/O systems. I/O system 524 may comprise, for example, a universal serial bus (USB) type system, an IEEE 1394 type system, or the like, to couple one or more peripheral devices to information handling system 500. Bus system 526 may comprise one or more bus systems such as a peripheral component interconnect (PCI) express type bus or the like, to connect one or more peripheral devices to information handling system 500. A hard disk drive (HDD) controller system 528 may couple one or more hard disk drives or the like to information handling system, for example Serial ATA type drives or the like, or alternatively a semiconductor based drive comprising flash memory, phase change, and/or chalcogenide type memory or the like. Switch 530 may be utilized to couple one or more switched devices to I/O bridge 522, for example Gigabit Ethernet type devices or the like. Furthermore, as shown in FIG. 5, information handling system 500 may include a radio-frequency (RF) block 532 comprising RF circuits and devices for wireless communication with other wireless communication devices and/or via wireless networks such as channel feedback system 100 of FIG. 1, for example where information handling system 500 embodies base station 110 and/or mobile station 114, although the scope of the claimed subject matter is not limited in this respect. Furthermore, at least some portion of base station 110 or mobile station 114 may be implemented by processor 510, for example the digital functions of base station 110 or mobile station 114 which may include processing of the baseband and/or quadrature signals, although the scope of the claimed subject matter is not limited in this respect.

Although the claimed subject matter has been described with a certain degree of particularity, it should be recognized that elements thereof may be altered by persons skilled in the art without departing from the spirit and/or scope of claimed subject matter. It is believed that the subject matter pertaining to feedback channel release and/or many of its attendant utilities will be understood by the forgoing description, and it will be apparent that various changes may be made in the form, construction and/or arrangement of the components thereof without departing from the scope and/or spirit of the claimed subject matter or without sacrificing all of its material advantages, the form herein before described being merely an explanatory embodiment thereof, and/or further without providing substantial change thereto. It is the intention of the claims to encompass and/or include such changes.