| 1. |
- Cho, Jeong-woo, 1978-, et al.
(author)
-
Infrastructure Support Increases the Capacity of Ad Hoc Wireless Networks
- 2005
-
In: VTC2005-FALL: 2005 IEEE 62ND VEHICULAR TECHNOLOGY CONFERENCE, 1-4, PROCEEDINGS. - : IEEE Press. - 0780391527 ; , s. 2663-2668
-
Conference paper (peer-reviewed)abstract
- In ad hoc wireless networks, one of the hottest research directions has been to increase the throughput capacity scaling with respect to the number of nodes n. Gupta and Kumar (2000) introduced a fixed random network model and showed that the throughput per source-destination pair is Theta(1/root nlogn) when the network is coordinated by a centralized entity. Grossglauser and Tse (2001) introduced a mobile random network model and showed that a source-destination pair acquires a constant throughput of Theta(1) assuming that delays incurred by mobile nodes with low mobility are tolerable.In this paper, we consider the capacity of ad hoc wireless networks with infrastructure support. Although Grossglauser-Tse mobile network model enables Theta(1) per-node throughput scaling, the mobility assumption may be too unrealistic to be accepted in some practical situations. One of the key observations we acquired is that the infrastructure support plays the same role played by the mobility in the Grossglauser-Tse model. We show that nodes can utilize the randomly located infrastructure support instead of mobility when nodes are nearly static. In this case, we show that the per-node throughput of Theta(1) is still achievable when the number of access points grows linearly with respect to the number of nodes. Furthermore., we show that there is additional per-node throughput improvement of Theta(1) when nodes are mobile.
|
|
| 2. |
- Dimou, Konstantinos, et al.
(author)
-
Generic link layer : A solution for multi-radio transmission diversity in communication networks beyond 3G
- 2005
-
In: VTC2005-FALL. - 0780391527 ; , s. 1672-1676
-
Conference paper (peer-reviewed)abstract
- Communication systems beyond 3G (B3G) will consist of a mixture of radio access technologies. For such systems the challenge is to provide a multi-radio access architecture that facilitates the interconnection of heterogeneous radio access networks and supports efficiently the various services. Achieving this interconnection in a transparent way for users and services requires extensions at link layer level. The Generic Link Layer (GLL), as proposed in the context of the Ambient Networks (AN) project addresses this challenge. The principal role of GLL within the AN multi-radio access architecture is to integrate different Radio Access Technologies (RATs) at the link layer and to facilitate their efficient interworking. A feature that is enabled by the use of GLL is termed multi-radio transmission diversity (MRTD). It implies a well-defined split of a data-flow over the available RATs; the main benefits thereby are gain in user QoS, in spectral efficiency and in robustness. In this paper we give the system architecture and the GLL functions required for the realization of MRTD. Then, the specific scenario of cooperation between UMTS and IEEE 802.11 is discussed.
|
|
| 3. |
- Koudouridis, Georgios P., et al.
(author)
-
Switched multi-radio transmission diversity in future access networks
- 2005
-
In: VTC2005-FALL. - 0780391527 ; , s. 235-239
-
Conference paper (peer-reviewed)abstract
- In this paper we study packet scheduling algorithms which exploit multi-radio transmission diversity in a multi-radio access network. We view the packet scheduling process as a combination of user scheduling and radio access allocation. A number of such schemes are proposed and their performance is evaluated via simulations in a multi-cell environment. It is shown that the use of such schemes across a total of six uncoupled radio accesses can result in average gains of up to 60% in spectral efficiency, as compared to scenarios where the radio accesses operate independently.
|
|
| 4. |
- Magnusson, Per, et al.
(author)
-
Multi-Radio Resource Management for Communication networks beyond 3G
- 2005
-
In: VTC2005-FALL: 2005 IEEE 62ND VEHICULAR TECHNOLOGY CONFERENCE, 1-4, PROCEEDINGS. - New York : IEEE. - 0780391527 ; , s. 1653-1657
-
Conference paper (peer-reviewed)abstract
- In ‘Beyond 3G’ wireless networking scenarios, characterized by the cooperation of multiple access networks comprising different radio access technologies, Multi-Radio Resource Management (MRRM) mechanisms fulfill a key role in enhancing system capacity, resource efficiency, coverage and service quality. This overview paper addresses the embedding of MRRM in the Ambient Networks concept, describes the principal MRRM functions and discusses distribution aspects and initial performance evaluation results. This work has been performed as part of the Ambient Networks project, an integrated project within the EU IST 6th Framework Programme. In ‘Beyond 3G’ wireless networking scenarios, characterized by the cooperation of multiple access networks comprising different radio access technologies, Multi-Radio Resource Management (MRRM) mechanisms fulfill a key role in enhancing system capacity, resource efficiency, coverage and service quality. This overview paper addresses the embedding of MRRM in the Ambient Networks concept, describes the principal MRRM functions and discusses distribution aspects and initial performance evaluation results. This work has been performed as part of the Ambient Networks project, an integrated project within the EU IST 6th Framework Programme.
|
|
| 5. |
- Wang, Wei, 1965, et al.
(author)
-
Evaluations of a 4G Uplink System Based on Adaptive Single-Carrier TDMA
- 2005
-
In: Proceedings IEEE Vehicular Technology Conference Fall, Dallas, Texas, USA. - 1550-2252. - 0780391527 ; 3, s. 1667-1671
-
Conference paper (peer-reviewed)abstract
- © 2005 IEEE. Recent research has shown that a single-carrier system with frequency domain equalization can be a potential alternative to an OFDM-based system in a single user case. In this paper we propose and evaluate an adaptive single-carrier TDMA uplink with scheduling for broadband cellular packet data systems. Frequency division duplex (FDD) is assumed. Multiuser channel estimation and channel prediction are considered. The adaptive modulation scheme is optimized to maximize the throughput including also the ARQ part of the transmission. Frequency domain equalization is employed to combat the inter-symbol-interference (ISI). With the proposed design, the simulation results show that the multiuser diversity gain in spectral efficiency is limited in a wideband system, which indicates that an OFDM based system might be a more favorable candidate.
|
|
