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Multi-band OFDM (MB-OFDM) UWB system was proposed for the applications of wireless personal area networks (WPANs). If the user mobility is concerned, handoff from a piconet to neighboring piconets is unavoidable. There are only few works considering soft handoff in OFDM systems. In this work, a novel soft handoff strategy for the MB-OFDM system is proposed. The system performance is analyzed and simulations are performed. Two receiving schemes, FixedFilter and DynamicFilter, are considered. Both FixedFilter and DynamicFilter improve the system performance. DynamicFilter is a little more complicated, but it provides larger performance gain. Finally, soft handoff can be achieved in the MB-OFDM system.

Adaptive ARQ is applied to a wireless network, altering retransmission policy according to content importance. By a video deadline-aware buffer discard policy, repeated transmission of expired packets and buffer overflow are mitigated, helping to maintain video quality. Multiple deadlines are applied according to picture type. The combined policy is demonstrated for a bluetooth piconet achieving fast recovery after disruption.

UWB (ultra-wide band) system that utilizes the unlicensed 3.1 - 10.6 GHz UWB band, as regulated in the United States by the Federal Communications Commission (FCC) Regulations, and there is a trend that UWB and Bluetooth technology are combined together for developing a next-generation low-power, low-cost ad hoc networking solution that will expand Bluetooth technology's current success. In this paper, we propose a novel piconet system model in which Bluetooth topology and MB-OFDM UWB devices are combined together to form a new ad hoc piconet system. For our proposed system, first, we used Bluetooth piconet's topology as reference to construct our proposed system's topology, considering both the path-loss effect and the using of TFC code to model our proposed scheme's inter-piconet interference. Second, we use the BER graph to evaluate our proposed system's performance taking into account of the Inter-piconet Interference influence, furthermore, we propose a 6-Bands MB-OFDM model to enhance our network's BER performance. Definitely, our model can be considered to provide a solid foundation for future interference aware UWB-Bluetooth protocols.

Bluetooth is a wireless communication technology that provides short-range, small-size, low-cost, and low-power connectivity among mobile devices. The MAC protocol for Bluetooth is based on a time division duplex (TDD) scheme, where the master determines channel access to all other slaves in the piconet. Hence, the polling scheme used by the master has a significant effect on the Bluetooth system performance. Accordingly, this paper proposes an enhanced limited round robin with a priority policy for Bluetooth. In simulations, the proposed scheduling algorithm demonstrates a better overall performance in a Bluetooth network.

In this paper, the performance of a hybrid medium access protocol in IEEE 802.15.3 has been studied. An analytical model has been developed for the coordination between the contention access period (CAP) and the contention-free channel time allocation period (CTAP). Given the traffic characteristic and the number of contending devices, the piconet coordinator (PNC) determines the duration of the CAP. Based on the successfully received requests and the scheduling scheme, the PNC decides the duration of the CTAP. Extensive simulations are performed to validate our analysis.

Many scatternet structures and routing algorithms have been proposed in recent years. The following paragraphs will analyze three scatternet structures. After that, we present a new topologic structure, named SolidRing, with its routing algorithm. Finally, there are some discussions on SolidRing’s performance.

Wireless sensor networks for sports monitoring applications support data collection from multiple sensor platforms. Important network requirements are data throughput, range, low power operation and number of sensor nodes. The Bluetooth specification has been designed for low power, medium data rate, cable replacement solutions and as such is useful for wireless sensor networks. However it has a limitation of a maximum number of eight active devices per Bluetooth network (Piconet). This project investigates and extends the capability of the Bluetooth specification and increases the usefulness for sensor applications. This has been achieved by utilising a combination of a network of Bluetooth wireless access points and innovative Bluetooth network structures. The Bluetooth network structures were created and controlled via the fixed Bluetooth access points, which act as root nodes for the network structures. The developed network structures for wireless sensing applications were Piconet Sharing, Scatternet Tree, Piconet Tree and Multiple Piconet. These network structures all allow more than seven Bluetooth devices to communicate to a fixed Bluetooth access point. A MATLAB based simulation tool was developed to compare the theoretical throughput per node for each network structure and validated experimentally. Bluetooth hardware was used to test the performance of the proposed network structures with current Bluetooth hardware and software implementations. Several limitations were discovered with the test Bluetooth hardware used and this impacted on the performance of the Bluetooth network structures. All network structures were shown (via data extrapolation) to provide the throughput per node required for the specific wireless sensing application. The developed network of Bluetooth root nodes combined with the developed network structures provided a complete solution suitable for wireless sensor applications. The same principles developed for Bluetooth based wireless sensor networks can be applied to other wireless applications that require a greater number of nodes than standard Bluetooth Piconets can provide. The developed network structures expand the applications that the Bluetooth Specification is suitable for.

IEEE 802.15.3 High-rate Wireless Personal Area Networks (WPANs) have been developed to communicate with devices within 10m at high speed. A mesh network made up of a parent piconet and several child piconets can support multi-hop communications. In this paper, we propose an efficient Channel Time Allocation (CTA) method and routing algorithm for multi-hop communications in IEEE 802.15.3 high-rate WPAN mesh networks. The proposed CTA allocation method allows sufficient CTA allocation for the relay PNCs. The proposed routing algorithm is tree-based, and the routing tables of parent PNCs and child PNCs are created by efficient device discovery process to find the shortest paths via parent PNCs or subordinate child PNCs. We evaluate the performance of the proposed algorithms via simulations. The proposed algorithms are shown to extend the communication range by multi-hop exchange of packets and to provide sufficient Channel Time Allocations (CTAs) for parent and child PNCs.

The SystemC modules of the Link Manager Layer and Baseband Layer have been designed in this work at behavioral level to analyze the performances of the Bluetooth standard. In particular the probability of the creation of a piconet in presence of noise in the channel and the power reduction using the sniff and hold mode have been investigated., Comment: Submitted on behalf of EDAA (http://www.edaa.com/)

In IEEE 802.15.3 MAC, CSMA/CA is used in contention periods (CPs) to send commands. The brief occurrences of CPs cause bursty channel access, thus conventional models based on Poisson arrivals and saturation assumptions are no longer applicable. In this paper, we model CP access in each superframe as a contention resolution problem by applying a frame aggregation strategy for efficient frame transmissions in CPs. Insight gained from this problem formulation motivates us to propose a novel Adaptive CP Suspend (ACS) scheme that is easily implemented using a CP Counter (CPC) at the piconet controller (PNC). The CPC counts down in each idle slot and resets with the appropriate contention windows size after each collision. When the CPC reaches zero, which implies the completion of the contention resolution process, the PNC can safely suspend the remaining CP and devices (DEVs) can go into SLEEP mode to save power. Simulation results show that ACS effectively adapts to changes in channel traffic, substantially shortening the effective region in a CP in which all active DEVs continue to sense the channel, and significantly reducing the system energy cost by allowing DEVs to turn off their radios during the suspended parts of the CPs.

This paper analyzes the capacity of medium access in a Bluetooth system. A random model of data transmission has been developed, establishing the relationship between data rate and transmission success rate (or data loss rate) for the first time, i.e., in a piconet, too large data rate will surely bring data loss for any scheduling. It is hoped that this work will form the basis for future research.

The paper presents the BlueGame project -- an ad-hoc multiplayer mobile game based on the Dungeons&Dragons board game. The main idea lies in the adoption of Bluetooth Piconet configuration and direct face to face contact of players in real environments.

Area coverage and Navigation are two fundamental requirements for robot applications. When multiple robots are fielded in a scene, coordination through communication becomes a natural pre-requisite. This paper focuses on the area coverage problem and proposes periodic exchange of state information related to location and coverage as a solution. The solution is based on pseudonet communication architecture that enables exchange of messages between the robots by setting up a Bluetooth piconet or scatternet and maintaining the same throughout the process of covering the area.

Future ubiquitous computing devices will need to communicate with other devices in an ad-hoc fashion, using minimum power and without the help of a central infrastructure. However, so far no single communication technology has established itself in the field of ubiquitous computing: many current wireless communication technologies seem to lack robustness, consume too much energy, or require an infrastructure to be viable candidates. `Large scale sensor network' ? networks of small devices equipped with sensors, microprocessor and wireless communication interfaces in a large area ? are a technology that has gained a great reliability. This may improve with the help of Bluetooth. In order to evaluate the suitability of the new and promising Bluetooth standard for such communication requirements, we have integrated a Bluetooth module into a sensor network node. It is expected to make a huge impact in wireless sensor networking domain. But still a number of questions remain unanswered regarding the practical utility of Bluetooth in large-scale sensor networks. In this paper, we discuss some of the issues involved in using the Bluetooth technology in large-scale wireless sensor networks.

This paper proposes a method to form a Bluetooth scatternet under the conference scenario. The principles and formulas for calculating network topologies are discussed in detail. The method is proved by implementation using commercially available Bluetooth devices. The scatternet topology can be star, mesh, ring and linked line, which is controlled by changing parameters like the number of maximum slaves in a piconet, the number of maximum piconets that a gateway Bluetooth device can participate, and whether loops are needed in the resulting scatternet. In this paper, we also present a lot of testing results from forming the real scatternet.

Ultra-wideband (UWB) technique has been considered as a possible candidate for high rate Wireless Sensor Network (WSN) because of its higher capacity with low power operation. The IEEE 802.15.3 Medium Access Control (MAC) protocol works on a Time Division Multiple Access (TDMA) basis within a piconet. With multiple overlapped piconets, the current protocol uses Parent/ Child (P/C) or Parent /Neighbor (P/N) configuration to avoid interpiconet interference, but the throughput of P/N or P/C cannot exceed that of single piconet. In this paper we propose an intelligent MAC protocol to cooperate with the UWB system based on Multi-Carrier Code Division Multiple Access (MC-CDMA). The proposed protocol uses Intermediate Sensor Device (ISDEV) to connect Piconet Coordinators and adaptively arrange 2 simultaneous data transmission links during each Channel Time Allocation (CTA). Our simulation results demonstrate the proposed scheme can achieve a higher throughput with an acceptable compromise at link success probability in multiple overlapped sensor networks.

In a large scale Bluetooth network, scatternet has been regarded as the only interconnection method among piconets. But, most Bluetooth devices do not support scatternet connection. Moreover, in high mobility situations, scatternet is not useful because of frequent disconnections and reconnections. Overlaid Bluetooth Piconets (OBP) interconnects piconets and forms a virtual scatternet. This demo shows the possibility of using OBP instead of Scatternet for Video Streaming.

Recently, ultra-wideband (UWB) technologies have attracted considerable attention for its capability, high data rate to achieve 480 Mbps, to wireless personal communications. In this paper, the problem of TCP and energy efficient transmission in IEEE 802.15.3 WPAN based on UWB technologies are addressed. Also, a simple power-efficient scheme for TCP transmission in accordance with IEEE 802.15.3 WPAN standard is proposed and NS2 is used for evaluating the performance of this proposal. The scheme design is driven by two major factors. The first one is that the scheme should provide high TCP throughput in a piconet and low end-to-end delay for TCP packets. The second one is that the scheme should be energy efficient since most mobile devices typically are powered by battery and have limited power capacity. In order to meet these requirements, the energy efficient design at the MAC layer and transport layer is taken into account by the proposed schema

In this paper, we proposed a medium access scheme for high-rate WPAN with ultra wideband (UWB) physical layer (PHY). In this scheme, piconet administration packets and user data packets are transmitted on two different layers which are divided by two spreading codes. Since this scheme needs only two spreading codes, the code can be designed with high autocorrelation and low cross-correlation. Therefore, the issue of complexity caused by the adoption of spreading code is greatly reduced. Moreover, the spreading code can be integrated with the property of UWB, and achieve high system performance. The advantages of the proposed scheme are that administration and data transmissions won't affect each other and average packet delay can be reduced. Due to the short delay of this scheme and large bandwidth of UWB, this scheme is very suitable for real-time multimedia services.

The capacity of UWB enabled wireless personal area networks is analyzed in a dense multipath environment. The performances of UWB systems employing a direct-sequence multiple access scheme are evaluated in terms of link outage probability and average aggregate network throughput, considering a network topology based on a clustered structure, formed by a multitude of uncoordinated coexisting piconets. We study the dependence of the system performances on some critical design choices, such as the Rake receiver scheme, the mono-pulse characteristics of the transmitted UWB signals, the structure of the piconet frame, the traffic characteristics. Results are obtained by applying a semi-analytical estimate procedure, which accounts of the large and small scale fading phenomena for the UWB indoor propagation channel.

In the event of PNC failure, the event of PNC leaving a piconet without a proper handover procedure, it is critical to have a scheme that allows one of the PNC capable DEVs to take over the role of PNC to minimize the interruption of services. A new proactive coordinator appropriation (PCA) scheme is proposed to prevent piconets from collapsing in the event of PNC failure. PCA is an efficient and reliable scheme that detects PNC failure in a timely manner, while minimizing the probability of false detection. An analytical comparison of PCA with the existing schemes of similar functionality is provided.

In this paper, we present a way to estimate the performance of successful requests in contention access period (CAP) of IEEE 802.15.3 accounting for dual carrier-orthogonal frequency division multiplexing-ultra wide band (DC-OFDM-UWB). It is important for a piconet coordinator (PNC) to schedule traffic of a piconet and will determine the duration of contention free period (CFP). Simulation results show that the analysis accurately predicts the performance of CAP in UWB PHY. This research should provide helpful insight to the implementation of UWB-based IEEE 802.15.3 wireless networks

Many Bluetooth researches are targeted to form efficient scatternets. However, scatternets do not have much popularity in general because many Bluetooth devices do not support scatternet capabilities and high mobility makes it difficult to keep the connectivity. Instead we choose temporary interconnection of piconets to reduce scatternet formation overhead. To compare several interconnection methods, we propose BlueProbe. BlueProbe finds out the allocated time slots size, which makes it apt for Bluetooth style TDMA capacity measurement. BlueProbe is applicable to both piconet and scatternet whether a cross traffic exists or not. Results based on our real testbed measurements show that the interconnection method is more important than the hop length and the number of simultaneous flows, whereas previous researches based on simulations concentrate on these two factors. Based on these results, we show efficient interconnection methods among Bluetooth Piconets.

Bluetooth is a mobile ad-hoc network aiming to serve voice, video, and data applications. Piconet is the smallest Bluetooth network unit that can be formed by a group of nodes. Scatternets are formed by joining piconets. In this paper, a practical scatternet formation protocol and an application utilizing this protocol are introduced. Scatternet formation protocols proposed until now are slow to establish the network for many application types. The suggested protocol is built on the experience gained from other scatternet formation protocols, ad-hoc routing protocols and sensor network routing protocols. It is practical, quick to establish, and easy to operate when data is flowing across the network.

Bluetooth is a well-known wireless technology designed for wireless personal area networks (WPAN). The Bluetooth device randomly searches and connects with other devices using the inquiry/inquiry scan and the page/page scan operations, resulting an uncontrolled scatternet topology. The unpredictable scatternet topology usually raises the problem of redundant traffic and causes inefficient communications. A traffic-aware restructuring protocol (TARP) is presented for partially restructuring a piconet or neighboring piconets by applying role switch mechanism. According to the recent routes and their traffic pattern, the TARP adjusts piconet structure by selecting the proper master from devices of a piconet and switches proper devices of neighboring piconets to reduce the route length and thus improve the power and bandwidth consumptions and transmission delay. Performance results show that TARP significantly improves network performance by reducing traffic load and power consumptions

This paper describes the in depth performance comparison and evaluation among three major solutions for forming multi-hop networks of Bluetooth devices (scatternet formation) and discovers the necessary key parameters related to scatternet formation. The three protocols considered in this paper are BlueTrees, BlueStars, and the "New protocol". By means of a thorough performance evaluation, protocol parameters and Bluetooth technology features that affect the duration of device discovery, have been identified. The effect of operations of the different protocols' on key metrics of the generated scatternets is also analyzed in this paper. The comparative performance evaluation showed that due to the simplicity of its operations and to its basic working requirements BlueStars is by far the fastest protocol for scatternet formation However, BlueStars produces scatternets with an unbounded, possibly large number of slaves per piconet, which imposes the use of potentially inefficient Bluetooth operations. A good compromise when interested in forming scatternets whose piconets have a bounded number of slaves is obtained by the New protocol. The comparative study presented in this paper clearly identifies the necessary trade-off factors of a scatternet formation protocol that affects its performance.

In IEEE 802.15.3 wireless personal area networks, all devices (DEVs) within a piconet communicate in a peer-to-peer manner. In this paper, we enhance the performance of intra-piconet communications by taking advantage of the multi-rate physical layer (PHY) and diverse application traffic characteristics. As higher PHY data rates are typically achievable over shorter transmission distances, a low rate link between two DEVs can potentially be replaced by a higher rate multihop connection through intermediate DEVs in the same piconet. A novel application-aware shortest path (AASP) algorithm is proposed for centralized intra-piconet route optimization, which finds the route that requires the minimum overall channel time allocation (CTA) based on the traffic parameters. Performance evaluations show that the effective CTA rates vary dramatically for different applications, and can be greatly increased by simply delaying the acknowledgments. Especially for low rate links and between unreachable DEV pairs, the AASP algorithm yields very high optimization ratios, which increase with frame payload size and the density of DEVs in the piconet.

In this paper, we propose an improved resource reservation algorithm ESRPT (Enhanced Shortest Remaining Processing Time) for bursty traffic based on IEEE 802.15.3 standard. In this algorithm, each transmitter reports current fragments number of the first MSDU (MAC Service Data Unit) and all of the fragments number of the remainder MSDUs in the pending transmission queue to PNC (piconet coordinator). In the next superframe, PNC firstly allocates part CTAs (Channel Time Allocation) for each stream based on the remainder fragments number of the first MSDU by SRPT rule, then allocates remainder CTAs for each stream based on all fragments number of remainder MSDUs by the same SRPT rule. This algorithm decreases the job failure rates of delay-sensitive video streaming efficiently at the cost of slightly increasing communication overheads. Simulation results show that our proposed ESRPT method achieves better performance in QoS for multimedia streams compared to the existing SRPT schemes.

This paper describes the in depth performance comparison and evaluation among three major solutions for forming multi-hop networks of Bluetooth devices (scatternet formation). The three protocols considered in this paper are BlueTrees, BlueStars, and the "new protocol". By means of a thorough performance evaluation, protocol parameters and Bluetooth technology features that affect the duration of device discovery, have been identified. The effect of the different protocols' operations on key metrics of the generated scatternets is also analyzed in this paper. The comparative performance evaluation showed that due to the simplicity of its operations and to its basic working requirements, BlueStars is by far the fastest protocol for scatternet formation. However, BlueStars produces scatternets with an unbounded, possibly large number of slaves per piconet, which imposes the use of potentially inefficient Bluetooth operations. A good compromise when interested in forming scatternets whose piconets have a bounded number of slaves is obtained by the New protocol. The comparative study presented in this paper clearly identifies the key features of a scatternet formation protocol that affects its performance

In this paper, we focus on the Bluetooth wireless network, analyzing its ability to support the Quality of Service (QoS) requirements defined by QoS sensitive applications. The QoS perceived by the application depends on the scheduling mechanisms chosen at the medium access layer. Hence, we propose to evaluate the ability of two Bluetooth scheduling algorithms, 1-RR/FIFO and 1-RR/EDF, to guarantee bounded transmission delays. First, we establish a bound on the worst case response time of any sporadic message using a worst case analysis.We then compare the computed bounds with the worst case response times obtained by simulation for different traffic distributions and show in which configurations our bounds are tight. We finally show how to extend the previous results taking into account message segmentation.

In this paper a Bluetooth-based sensor network for mobile telemedicine system is presented. The system uses smart sensor nodes organized in a Bluetooth piconet controlled by an access point. Observed data is processed in nodes and can be transferred to remote database. At last, we point out it is the future work to develop a scatternet.

In Bluetooth version 1.0, the frequency to be shared has been resolved by the specific part of the digits of the Device clock and the Bluetooth address in the given piconet. Basic pattern was a kind of pseudo-random fashion using 79 frequencies in the ISM band. At this point, a problem might occur if there were more than two devices using the same frequency within the shared range. In this paper, we proposed a software-based adaptive frequency hopping method so that more than two wireless devices can stay connected without frequency collision. Suggested method was implemented with HDL (Hardware Description Language) and automatically synthesized and laid out. The adaptive frequency hopping circuit was implemented in a prototype and showed its operation at 24mHz correctly.

A major issue to be addressed in the design, operation and applications of Bluetooth system is interference. This paper presents the results of interferences study investigating the impact of electromagnetic interference (EMI) and co-channel interference on Bluetooth receiver. Results are based on simulations by means of different scenarios. Preliminary results show that the performance of Bluetooth will be degraded in presence of interferences, being necessary to design a more robust Bluetooth receiver

In recent years, UWB has received much attention as a suitable physical layer (PHY) for wireless personal area networks (WPANS). UWB allows for low cost, low power, high bandwidth, short reach communication well suited for personal operating spaces. One of the key features offered by UWB is very accurate ranging between a transmitter/receiver pair. The IEEE 802.15.3 is a MAC protocol that has been proposed for WPANs. In this MAC, a combination of CSMA/CA and TDMA is used to achieve channel scheduling. The TDMA component ensures only one transmitter/receiver pair within a piconet is active at any given time thereby ensuring an exclusion region that covers the whole piconet. In this paper, we propose a less stringent scheduling mechanism that allows for concurrent communication between UWB transmitter/receiver pairs within a piconet. Exclusion is necessary only when the communicating entities are close enough such that interference between them would adversely affect successful reception of data at the receivers. The piconet coordinator (PNC) uses the ranging information provided by UWB to accurately position transmitters and receivers. The PNC schedules parallel transmissions between distinct transmit/receive pairs as long as they do not interfere. We present the results of our simulations of our proposed modifications and show that the network throughput can be significantly increased with very little change to the 802.15.3 MAC.

Designed for high data rate wireless personal area networks (WPANs), the IEEE 802.15.3 medium access control (MAC) protocol fits well with emerging technologies such as ultra-wideband (UWB). In an 802.15.3 piconet, all MAC frames are exchanged in a peer-to-peer manner between devices (DEVs) to allow efficient ad hoc operations while the piconet coordinator (PNC) only provides timing synchronization in the piconet; thus peer discovery is an essential function. If two peer DEVs in a piconet are out of transmission range, the standard peer discovery method will fail, and a costly upper layer routing procedure is required to complete the peer connection. In this paper, we propose a third-party handshake protocol (3PHP) at the 802.15.3 MAC layer to provide reliable and prompt peer discovery between out of range DEVs in a piconet via the PNC. It removes the overhead of unsuccessful peer discovery in the standard method, and completely eliminates costly upper layer routing between these DEVs by means of a simple and efficient MAC layer PNC forwarding. The performance of the proposed scheme is evaluated by a novel CSMA/CA delay analysis for the contention access period (CAP). Analytical and simulation results show that for uniformly distributed DEVs over the maximum coverage of a piconet, up to 41.3% of intra-piconet peer discovery procedures may fail if the standard method is used. The cost of unsuccessful MAC peer discovery and consequent routing is very high. The expected peer discovery time for 3PHP is 100 mum lower than that of the standard method when the latter is successful in peer discovery, and up to 10 times faster than the standard method with network layer routing when the standard method is unsuccessful in connecting the peer DEVs. 3PHP also significantly reduces the peer discovery failure probability. Therefore, the proposed 3PHP scheme brings huge performance gain with minimum cost, and successfully resolves the potential connectivity issue in an IEEE 802.153 piconet

In this paper, we investigate beaconing problems in Wireless Personal Area Networks (WPANs) with distributed control, which is being developed by Multi-Band OFDM Alliance. The problems are related to collision that is caused by multiple access to a piconet; and the collision resolution that is used in the MBOA MAC, i.e. random slot allocation for devices’ beacons. The collision problem and the current resolution may cause deadlock and prevent other devices from joining a piconet. We propose new solutions to resolve the collision without causing potential deadlock. We develop an analytical model to evaluate performance of the new schemes. The model can also be employed to determine parameters to achieve optimized performance.

Bluetooth is a wireless specification delivering short-range radio communication between electronic devices that are equipped with specialized Bluetooth chips. It lets nearly all devices talk to one another by creating a common language between them. The basic Bluetooth network topology (referred to as a piconet) is a collection of slave devices operating together with one master. A multi-hop ad-hoc network of piconets in which some of the devices are present in more than one piconet is referred to as a scatternet. Efficient scatternet data flow requires design of inter-piconet scheduling algorithms. This paper presents and evaluates a fair and efficient scheduling algorithm for inter-piconet based on the Bluetooth hold mode. During intra-piconet scheduling, we have used soft- QoS based SFPQ algorithm. SFPQ is a fair and efficient polling algorithm. Finally, we evaluate the performance of proposed algorithm regarding efficient and fairness inter-piconet scheduling via simulation and show that the proposed algorithm outperforms Load Adaptive Scheduling Algorithm.

Current Medium Access Control (MAC) layer de- sign for Ultra-Wideband (UWB) communication relies heavily on existing MAC protocols and architectures in order to maintain backward compatibility. However, it remains to be seen if the existing MAC protocols adequately support the UWB Physical layer (PHY) in the applications envisioned for UWB systems. In this work, we propose a new MAC-layer protocol that is suitable for an Impulse-Radio (IR) UWB physical layer, which is based on a clustered code-assignment approach. Specifically, the proposed scheme is based on Time-Hopped CDMA (TH-CDMA) where a "code-broker" assigns spreading codes to users that communicate within a cluster or "piconet". The performance of the proposed scheme is compared with the CSMA and Receiver- based Code Assignment (RCA) schemes in different scenarios. It is demonstrated that spread-spectrum schemes outperform the CSMA protocol in terms of throughput and latency.

Bluetooth which operates in the 2.4 GHz ISM band provides short range, low cost, low power pico-cellular wireless connectivity. It intends to become the wireless personal area network standard itself. The Bluetooth specification proposes a round robin scheduler as possible solution for scheduling slaves in a Bluetooth piconet. However, this basic scheme performs badly under asymmetric traffic conditions. Recently, several polling schemes have been proposed to improve performance on asymmetric transmissions and to enhance the performance of real-time traffic. In this paper, we present a new polling algorithm for Bluetooth piconet that supports both delay and bandwidth guarantees and aims to remain fair and efficient with asymmetric flow rates. We present an extensive set of simulations and provide performance comparisons with round robin. And the results show that the performance of our algorithm can be better than that of the round robin. In addition, our modification does not introduce any control overhead

The IEEE 802.15.3 Medium Access Control (MAC) protocol is designed to support low power and high rate Wireless Personal Area Networks (WPANs). It works on a Time Division Multiple Access (TDMA) basis within a piconet, which guarantees interference-free connections. However, the current protocol is not efficient for Simultaneously Operating Piconets (SOPs), which are linked by the parent/child (P/C) and parent/neighbor (P/N) relationships. It provides interference mitigation but the throughput is limited since the channel time is exclusively allocated. In this paper we propose Intelligent Channel Time Allocation (Intelligent CTA), which includes Public CTA and Normal CTA, to intelligently manage the inter-piconet interference (IPI). The proposed scheme is able to greatly reduce the IPI. Based on the DS-UWB system, the simulation results show that the proposed scheme can effectively support the coexistence of SOPs and it can achieve higher throughput without significant loss of link success probability (LSP) in the SOPs.

U ovom radu objašnjen je princip povezivanja i komunikacije u Bluetooth bežičnoj mreži. Bluetooth bežična tehnologija najpoznatiji je predstavnik mrežnih tehnologija u sve popularnijim osobnim mrežama (PAN), This paper gives an explanation for connection and communication principles of the Bluetooth wirelles network. Bluetooth wireless technology is the most popular network technology for personal area networking (PAN).

The video game market is currently the fastest growing form of E-entertainment. Today’s players want more from their experience, like massively multiplayer online games and the ability to play anytime/anywhere using cell phones, PDAs, and consoles. For developing multiplayer online games for cell phones, we report an effort performed at the COMSATS institute of information technology (Lahore Campus, Pakistan) as the final project of MCS. We developed two players Pacman game for Nokia series 60 handsets in J2ME and Bluetooth. Paper presents, how Pacman game is developed for resource constraints devices by our own revealed shortest path finding logic known as tracking system, which allows to the game engine just to fetch out next direction that Pac should have to use in order to run on the shortest path after Pac. In two-player mode, Pacman game allows both the players to play the game on two different cell phones simultaneously, these cell phones work on client server Piconet architecture for communication on Bluetooth link.

In this paper, we focus on the ability of Bluetooth to support Quality of Service (QoS) requirements expressed by QoS sensitive applications. We focus on the quantitative QoS guarantee that can be granted to an uplink or downlink flow in terms of end-to-end delay. Two approaches are presented. The deterministic one is based on a worst case analysis and leads to a deterministic bound which is unfrequently reached. The probabilistic approach, based on the probability density function of the response time, is then introduced to evaluate the probability of missing a given deadline. This study shows that delays much smaller than the deterministic bound can be guaranteed with probabilities close to one. An admission control derived from these results is then proposed, providing a probabilistic QoS guarantee to uplink or downlink flows in a Bluetooth piconet.

Bluetooth is a wireless communication technology, aimed at supporting connectivity among close proximity mobile devices. Bluetooth enables the design of low-power, low-cost, and small-size radios. Bluetooth’s MAC is a polling based protocol, where a central Bluetooth unit (master) determines channel access to all other nodes (slaves) in the network (piconet). One of the open research problems in Bluetooth is the design of efficient scheduling protocols. This paper proposes a polling policy that aims to achieve increased system throughput and reduced packet delays while providing reasonable fairness among all traffic flows, even in the presence of asymmetric traffic rates and unpredictable channel error conditions. Simulation results confirm that our proposed policy achieves higher throughput, lower packet delays with reasonable fairness among all the connections, compared to previous work in the literature.

Mechanisms based on frequency hopping have been widely used to enable short-range wireless networks to use resources from the unlicensed spectrum without frequency planning. Bluetooth piconet is a prime example of an FH-based network with unlicensed operation. As a price for open access, the piconet may experience adverse interference from other collocated FH piconets or other wireless devices that are transmitting in the same unlicensed band. A basic approach to mitigate this interference is that the piconet applies adaptive FH (AFH) and attempts to hop over a set (hopset) of less interfered channels. On the other hand, the regulation of unlicensed operation sets constraints on possible hopset adaptations. In this article we present two novel AFH strategies: adaptive frequency rolling (AFR) and dynamic AFH (DAFH). AFR avoids self-interference while preserving the dynamics of spectrum usage as required by the current regulation. DAFH is a distributed mechanism by which collocated piconets select nonconflicting hopsets while trying to keep the hopset size as large as possible. DAFH is not completely compliant with current regulations, but the rationale given for its design contains new rules of behavior for the unlicensed spectrum. Both approaches significantly outperform the conventional AFH strategy

This paper proposes a non-coherent UWB ranging scheme employing 1-bit ADCs and energy collection for precision asset location within simultaneously operating piconets (SOP). To estimate the time of arrival (ToA) of the first multipath, the proposed method is based on the correlation operation with template signal. For an appropriate 1-bit ADC process, the threshold value is extracted adaptively from sampled binary data. To improve the ranging accuracy on the existence of SOPs, gold code is assigned to each piconet. Corresponding to the proposed ranging scheme, its performance is verified by conducting simulations in two types of channel conditions. The simulation results show that the proposed ranging scheme on the existence of multiple SOP performs well even in condensed multipath environment.

In this paper, we proposed a new inter-piconet scheduling algorithm based on HOLD mode, a power saving mode of Bluetooth, to reduce the average delay of inter-piconet packets and maximize the utilization of the bridge as possible. The delay of inter-piconet traffic is incurred by the phenomenon that a bridge stays in a piconet which has no inter-piconet traffic to be processed while inter-piconet packets of other piconets have to wait in queues. Consequently, our proposed scheme aims at determining the time duration which the bridge should spend in different piconet according to the traffic pattern so that the idle time of a bridge can be minimized. In addition, our design completely follows Bluetooth specification, i.e., there is no need to modify the specification or add any other device. So it is easy to implement and integrate the proposed scheduling algorithm into Bluetooth specification. Finally, we show the superiority of the proposed scheme on average delay, throughput, and scalability by simulation

Multiple Bluetooth piconets operating in the globally available 2.4 GHz industrial, scientific and medical (ISM) band are likely to co-exist in a physical environment, supporting applications such as wireless earphones, keyboards etc. An independently operating Bluetooth piconet will inevitably encounter the interference from collocated piconets, which results in both individual piconet and overall network performance degradation. We propose a simple time- synchronisation scheme among co-existing Bluetooth piconets that yields considerable performance improvements as compared to uncoordinated piconets. We introduce a new state to the Bluetooth link controller that does not require any changes to the existing Bluetooth hardware. The proposed scheme synchronises the collocated piconets in a totally blind fashion and incurs minimal overhead to the participating piconets. The performance of the scheme is measured by evaluating metrics such as packet error rate, individual piconet throughput and aggregate network throughput using an extensive analytical model. Furthermore, the effect of partial synchronisation among collocated piconets is also investigated.

In this paper, we address the issue of co-existence of Bluetooth (BT) and Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA)-based Wireless Local Area Networks (WLANs) in the license free 2.4 GHz band. Specifically, the probabilistic treatment presented in the following investigates the effect of the slotted p-persistent CSMA/CA system on a co-existing BT piconet. A closed-form expression for packet error probability (PEP) in BT as a function of CSMA/CA parameters such as the persistence probability, probability of packet generation and the number of users is derived. The analytical model entails different BT packet types, frequency hopping guard time, and different traffic models in the BT piconet.