Abstract:
Briefly, in accordance with one or more embodiments, a data packet to be transmitted is encoded and one or more subpackets are generated from the encoded data packet. A first bit pattern is applied to a first symbol of the subpackets to provide a constellation, and a different bit pattern is applied to a next adjacent symbol in the constellation for one or more additional symbols. The data packet is then modulated according to the constellation and transmitted one or more times until the data packet is decoded by a receiver or until said transmitting is aborted according to a hybrid automatic repeat request error correction technique.

Description:
BACKGROUND 
     In wireless communication systems, hybrid automatic repeat request (HARQ) is utilized as an error-control method in which a data packet is repeatedly transmitted until the receiving device successfully decodes the packet. In some systems, the data packet may be subdivided into two or more subpackets transmitted at a varying code rate for each subpacket in order to help support HARQ transmission. In some HARQ processes, a retransmission bit may be mapped into the same layer of the constellation that is highly modulated, which may degrade decoding performance on the receiver side. In order to prevent retransmission bits from being allocated into the same level as the initial transmission bits, constellation rearrangement schemes may be employed in which the data bits may be rearranged from one transmission to the next transmission. However, with such schemes the adjacent bits in same transmission may still be mapped into the same constellation layer as a highly modulated data, which may impact the decoding performance on the receiver side. 
    
    
     
       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 coding circuit with subpacket generation in accordance with one or more embodiments; 
         FIG. 2  is a block diagram of a constellation rearrangement scheme in accordance with one or more embodiments; 
         FIG. 3  is a diagram of an interlaced constellation symbol scheme for initial transmission and 16 QAM HARQ retransmission in accordance with one or more embodiments; 
         FIG. 4  is diagram of an interlaced constellation symbol scheme for 64 QAM HARQ retransmission in accordance with one or more embodiments; 
         FIG. 5  is a block diagram of a constellation rearrangement circuit in accordance with one or more embodiments; 
         FIG. 6  is a flow diagram of a method for interlaced symbol constellation transmission in accordance with one or more embodiments; 
         FIG. 7  is a block diagram of a wireless wide area network capable of utilizing interlaced symbol constellation transmission in accordance with one or more embodiments; and 
         FIG. 8  is a block diagram of an information handling system capable of utilizing interlaced symbol constellation transmission 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 coding circuit with subpacket generation in accordance with one or more embodiments will be discussed. As shown in  FIG. 1 , a channel coding circuit  100  includes an encoder  110  to encode data to be transmitted to a receiving device. In one or more embodiments, encoder  110  may comprise a convolutional turbo code (CTC) encoder with a rate of 1/3 for example as specified in the Institute of Electrical and Electronics Engineers (IEEE) 802.16m standard, to perform channel coding. Encoder  110  provides coded data to a subpacket generation circuit  112  which comprises a bit separation circuit  116 , a subblock interleaver circuit  120 , and a bit grouping circuit  124 . The output of subpacket generation circuit  112  is provided to a bit selection circuit  114 . Bit separation circuit  116  separates the data coded by encoder  110  into two or more subblocks  118 . The subblocks are then provided to corresponding subblock interleaver circuits  122  of subblock interleaver circuit to interleave the bits of the subblocks according to an interleaving scheme. The interleaved bits are then grouped into a symbol constellation comprising one or more symbol arrangements  126  at bit grouping circuit  124  for selection by bit selection circuit  114 . In one or more embodiments, as will be discussed in detail below, channel coding circuit  100  may implement an interlaced symbol constellation scheme in which the modulation mapping rule is different for two adjacent symbols within the same transmission. Furthermore, for different HARQ transmissions, the pattern for a given symbol may be different for one or more retransmissions of the data. A block diagram of a constellation rearrangement scheme for HARQ is shown in and described with respect to  FIG. 2 , below. 
     Referring now to  FIG. 2 , a block diagram of a constellation rearrangement scheme in accordance with one or more embodiments will be discussed. As shown in  FIG. 2 , a modulation circuit  210  receives data  214  to be modulated before transmission. The data  214  is provided to a constellation bit rearrangement circuit  216 , which applies a particular constellation rearrangement scheme version  212  to rearrange one or more bits of the data  214 . After bit rearrangement, the rearranged data  214  is provided to a constellation mapping circuit  218  to provide a symbol constellation  220  to be transmitted. In order to prevent the retransmission bits from being allocated into the same level as the initial transmission bits, the constellation rearrangement scheme  212  are provided to implement HARQ transmission as discussed in further detail below to achieve constellation rearrangement bit-grouping gain without increasing the complexity of channel coding circuit  100 . For example, constellation rearrangement scheme  212  may involve swapping a most significant bit (MSB) of the data with a least significant bit (LSB), an inversion of a signaling bit (SB), exchanging in-phase data streams from one symbol to another, and so on. Furthermore, the bits may be interlaced to provide an interlaced symbol constellation scheme as shown in and described with respect to  FIG. 3  and  FIG. 4 , below. 
     Referring now to  FIG. 3 , a diagram of an interlaced symbol constellation scheme at initial transmission and for 16 QAM HARQ retransmission in accordance with one or more embodiments will be discussed. An example initial symbol constellation  310  is shown for 16 quadrature amplitude modulation (16 QAM) modulation. Constellation  310  may comprise four symbols, s 1 , s 2 , s 3 , and s 4 , wherein each symbol comprises four bits for in-phase components i 1  and i 2  and quadrature components q 1  and q 2 . As shown in  FIG. 3 , adjacent symbols are arranged to have a different pattern for the symbols respective bits. For example, two patterns may be utilized such that the first symbol, s 1 , has the bits arranged in a first pattern, pattern  1 , and the next symbol, s 2 , has the bits arranged in a second pattern, pattern  2 . The patterns may then be alternated such that any two adjacent symbols have a different pattern of bits. 
     Similarly, an example initial symbol constellation  312  is shown for 64 quadrature amplitude modulation (64 QAM) modulation. Constellation  312  may comprise three symbols, s 1 , s 2 , and s 3 , each comprising a pattern of six bits for in-phase components i 1 , i 2 , and i 3 , and quadrature components q 1 , q 2 , and q 3 . Constellation  312  follows the rule that adjacent symbols have different bit patterns. For example, using three patterns, the first symbol, s 1 , may have a first bit pattern, pattern  1 , second symbol, s 2 , may have a second bit pattern, pattern  2 , and third symbol, s 3 , may have a third bit pattern, pattern  3 . The constellations  310  and  312  shown in  FIG. 3  illustrate example arrangements of bits in a symbol constellation for an initial transmission of HARQ transmission. Other bit patterns and/or symbol arrangements may likewise be implemented that general follow the rule that adjacent symbols in a given transmission have different bit patterns, and the scope of the claimed subject matter is not limited in this respect. 
     To illustrate an interlaced symbol constellation rearrangement for HARQ transmission, constellation  310  represents an arrangement of bits for an initial 16 QAM transmission, and constellation  314  represents a subsequent arrangement of bits for the second transmission. As shown, bits i 1  and i 2  of symbol s 1  are swapped from constellation  310  to constellation  314 . Likewise, adjacent bits q 1  and q 2  are swapped from constellation  310  to constellation  314 , and so on for the bits of the other symbols. In effect, this results in the bit pattern for symbol s 1  to switch from pattern  1  to pattern  2 , and the bit pattern for symbol s 2  to switch from pattern  2  to pattern  1 . In general, the symbol bit patterns are different for a given symbol are different from transmission to transmission, in addition to following the rule that adjacent symbols in a given transmission also have different bit patterns. In one or more embodiments, the patterns for the first transmission and the second transmission may be represented as:
 
{p 1 ,p 2 , . . . , p K }  1 st  transmission
 
{p 1 ′,p 2 ′, . . . , p (K−1) ′}  2 nd  transmission.
 
In general, the interlacing rule may result in a shift of the bit patterns from a first transmission to a next transmission. Such a shift in the bit pattern mapping may be represented by a constellation mapping rule for the ith transmission as:
 
shift({p 1 ,p 2 , . . . , p K },i)
 
where K is the modulation order, although the scope of the claimed subject matter is not limited in this respect. A similar constellation rearrangement scheme for 64 QAM is shown in and described with respect to  FIG. 4 , below.
 
     Referring now to  FIG. 4 , a diagram of an interlaced symbol constellation scheme for 64 QAM HARQ retransmission in accordance with one or more embodiments will be discussed. The initial constellation  312  pattern is shown for 64 QAM. For optimum performance, extra constellation rearrangement patterns may be utilized, for example for the second transmission as shown in constellation  410 . In one embodiment, by shifting the third, fourth, fifth, and sixth bits in a symbol to the previous position of the first, second, third, and fourth bits, and shifting the first and second bits to the right, what was the first pattern for symbol s 1  in the initial transmission becomes the second pattern for symbol s 1 . Likewise, symbol s 2  has pattern  3 , and symbol s 3  has pattern  1  in the second transmission as shown at constellation  412 , which is a retransmission for HARQ transmission. Alternatively, constellation  414  shows another example constellation pattern for the second transmission wherein pattern  1  in constellation  312  changes to pattern  1   a  in constellation  414  for symbol s 2 . Likewise, pattern  2  changes to pattern  2   a  and pattern  3  changes to pattern  3   a  from constellation  312  to constellation  412  for symbol s 2  and symbol s 3 , respectively. Thus, when implementing the symbol constellation rearrangement rules that adjacent symbols within a given transmission, including the initial transmission, have different bit patterns, and that the bit pattern for a given symbol changes from transmission to transmission, constellation rearrangement bit-grouping gain may be achieved. As a result, the performance of the initial transmission and subsequent transmissions may be increased without requiring additional complexity with channel coding circuit  100 , which has been confirmed via simulation results. For example, initial transmission performance may be increased since the scheme described herein may avoid the contiguous bit being integrated into a same constellation layer. Furthermore, performance may be increased via constellation rearrangement for HARQ retransmissions. In addition, the same module may be utilized to perform bit grouping and HARQ constellation rearrangement in a given channel coding circuit  100 . Implementation of the present scheme may also result in enhanced diversity gain. An example of how channel coding circuit implements such an interleaved symbol constellation rearrangement is shown in and described with respect to  FIG. 5 , below. 
     Referring now  FIG. 5 , a block diagram of a constellation rearrangement circuit in accordance with one or more embodiments will be discussed. As shown in  FIG. 5 , channel coding circuit  100  utilizes the subblock interleavers  122  to interleave the bits of the corresponding subblocks  118  into symbol arrangements  126  according to the interlaces symbol constellation scheme as described herein. For HARQ retransmissions, symbols  512 ,  514 ,  516 ,  518 , and so one are arranged in a first retransmission  510  to have a bit pattern according to the rule that adjacent symbols have different bit patterns for the same transmission. Likewise, from transmission to transmission, for example from first retransmission  510  to second retransmission, the constellation pattern in the second retransmission may have a first part  520  that has the same pattern as in the constellation of the first transmission  510 , but may have a second part  522  that is a different pattern that is different from the corresponding part of the constellation of the first retransmission  510 . As a result, the second retransmission may follow the rule of the present constellation rearrangement scheme that the symbol constellation patterns in subsequent transmissions are different from the pattern of a previous transmission. It should be noted that the symbol constellation pattern changes from a first retransmission  510  to a second retransmission  512  may be extrapolated to any number of retransmissions in a HARQ transmission system, and furthermore other pattern changes may likewise be utilized in addition to the one shown in  FIG. 5 , and then scope of the claimed subject matter is not limited in this respect. An example flowchart of a method for interlaced symbol constellation rearrangement for HARQ transmission is shown in and described with respect to  FIG. 6 , below. 
     Referring now to  FIG. 6 , a flow diagram of a method for interlaced symbol constellation rearrangement for HARQ transmission in accordance with one or more embodiments will be discussed. As shown in  FIG. 6 , method  600  illustrates one particular arrangement, however in alternative embodiments method  600  may include more or fewer blocks than shown, and/or a different ordering of the blocks, and the scope of the claimed subject matter is not limited in these respects. At block  610 , a data packet to be transmitted is encoded, for example using a 1/3 CTC encoding scheme. One or more subpackets may be generated at block  612  from the encoded data by channel encoding circuit  100  of  FIG. 1 . A first mapping rule may be applied to a first symbol at block  614 , and a different mapping rule may be applied to the next adjacent symbol at block  616  until all symbols in a constellation are mapped as determined by decision block  618 . This arrangement the rule of the present scheme that adjacent symbols in a given transmission should have a different bit pattern as determined by the mapping rule. After all the symbols in a constellation are mapped, the data packet may be transmitted at block  620  to a receiving device which implements a HARQ process by feeding back either an acknowledgement (ACK) message or a negative acknowledgment (NACK) message. If the transmitting device receives a NACK message at block  622 , the mapping rule may be shifted or otherwise changed or interleaved as discussed herein for each subsequent transmission at block  624  until an ACK message is received at block  622  or otherwise until a timeout or maximum number of retransmissions is reached. This arrangement satisfies the rule of the present scheme that different transmissions should have a different symbol constellation arrangement than a previous transmission. If an ACK message is received at block  622 , then the next data packet to be transmitted may be processed at block  626 , and method  600  may continue for the next data packet. It should be noted that method  600  is merely one example method for implementing a scheme for interlaced symbol constellation rearrangement among various other possible methods, and the scope of the claimed subject matter is not limited in this respect. An example diagram of a wireless network on which devices of the network may implement the present symbol constellation rearrangement scheme is shown in and described with respect to  FIG. 7 , below. 
     Referring now to  FIG. 7 , a block diagram of a wireless wide area network capable of utilizing interlaced symbol constellation rearrangement for HARQ transmission in accordance with one or more embodiments will be discussed. As shown in  FIG. 7 , network  700  may be an internet protocol (IP) type network comprising an internet  710  type network or the like that is capable of supporting mobile wireless access and/or fixed wireless access to internet  710 . In one or more embodiments, network  700  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  700  may be in compliance with a Third Generation Partnership Project Long Term Evolution (3GPP LTE) or a 3GPP2 Air Interface Evolution (3GPP2 AIE) standard, and/or a Fourth Generation (4G) standard, or the like. In general, network  700  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)  712  is capable of coupling with base station (BS)  714  to provide wireless communication between subscriber station (SS)  716  and internet  710 . Subscriber station  116  may comprise a mobile type device or information handling system capable of wirelessly communicating via network  700 , for example a notebook type computer, a cellular telephone, a personal digital assistant, or the like. ASN  712  may implement profiles that are capable of defining the mapping of network functions to one or more physical entities on network  700 . Base station  714  may comprise radio equipment to provide radio-frequency (RF) communication with subscriber station  716 , 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  714  may further comprise an IP backplane to couple to internet  710  via ASN  712 , although the scope of the claimed subject matter is not limited in these respects. 
     Network  700  may further comprise a visited connectivity service network (CSN)  724  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  726 , and the scope of the claimed subject matter is not limited in these respects. Visited CSN  724  may be referred to as a visited CSN in the case for example where visited CSN  724  is not part of the regular service provider of subscriber station  716 , for example where subscriber station  716  is roaming away from its home CSN such as home CSN  726 , or for example where network  700  is part of the regular service provider of subscriber station but where network  700  may be in another location or state that is not the main or home location of subscriber station  716 . In a fixed wireless arrangement, WiMAX type customer premises equipment (CPE)  722  may be located in a home or business to provide home or business customer broadband access to internet  710  via base station  720 , ASN  718 , and home CSN  726  in a manner similar to access by subscriber station  716  via base station  714 , ASN  712 , and visited CSN  724 , a difference being that WiMAX CPE  722  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  716  is within range of base station  714  for example. In accordance with one or more embodiments, operation support system (OSS)  728  may be part of network  700  to provide management functions for network  100  and to provide interfaces between functional entities of network  700 . Network  700  of  FIG. 7  is merely one type of wireless network showing a certain number of the components of network  700 , however the scope of the claimed subject matter is not limited in these respects. 
     Referring now to  FIG. 8 , a block diagram of an information handling system capable of utilizing interlaced symbol constellation rearrangement for HARQ transmission in accordance with one or more embodiments will be discussed. Information handling system  800  of  FIG. 8  may tangibly embody one or more of any of the network elements of network  700  as shown in and described with respect to  FIG. 7 . For example, information handling system  800  may represent the hardware of base station  714  and/or subscriber station  716 , with greater or fewer components depending on the hardware specifications of the particular device or network element. Although information handling system  800  represents one example of several types of computing platforms, information handling system  800  may include more or fewer elements and/or different arrangements of elements than shown in  FIG. 8 , and the scope of the claimed subject matter is not limited in these respects. 
     Information handling system  800  may comprise one or more processors such as processor  810  and/or processor  812 , which may comprise one or more processing cores. One or more of processor  810  and/or processor  812  may couple to one or more memories  816  and/or  818  via memory bridge  814 , which may be disposed external to processors  810  and/or  812 , or alternatively at least partially disposed within one or more of processors  810  and/or  812 . Memory  816  and/or memory  818  may comprise various types of semiconductor based memory, for example volatile type memory and/or non-volatile type memory. Memory bridge  814  may couple to a graphics system  820  to drive a display device (not shown) coupled to information handling system  800 . 
     Information handling system  800  may further comprise input/output (I/O) bridge  822  to couple to various types of I/O systems. I/O system  824  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  800 . Bus system  826  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  800 . A hard disk drive (HDD) controller system  828  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  830  may be utilized to couple one or more switched devices to I/O bridge  822 , for example Gigabit Ethernet type devices or the like. Furthermore, as shown in  FIG. 8 , information handling system  800  may include a radio-frequency (RF) block  832  comprising RF circuits and devices for wireless communication with other wireless communication devices and/or via wireless networks such as network  800  of  FIG. 8 , for example where information handling system  800  embodies base station  814  and/or subscriber station  816 , although the scope of the claimed subject matter is not limited in this respect. In one or more embodiments, RF block  832  may comprise a radio-frequency transceiver, and baseband processing of received and transmitted signal may be performed by processor  810  and/or processor  812 , for example processing of baseband and/or quadrature signals, although the scope of the claimed subject matter is not limited in these respects. 
     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 interlaced symbol constellation mapping for wireless communication 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.